摘要:

LAPWORTH AND HAKN : MENTEIYI, ACETOACETATB. 1409 CXLVII1.-Optically Active Esters of &Ketonic and P- A lclehydic Aczds. Purt I". Menthyl Acetoacetate. By A. LAPWORTH and A. C. OSBORN HANN. IN continuation of researches on the tautomerism of P-ketonic esters, the study of an optically active ester of acetoacetic acid was undertaken, as little is yet known as to the mode in which intercon- version of the enolic and ketonic Forms of ethyl acetoacetate is brought about, for although it is already well established that bases in small quantities are effective in establishing equilibrium, tke effect of acids has not been properly investigated. After a number of attempts had been made to obtain the menthyl ester from menthyl acetate by the action of metallic sodium-a method which was found to afford the desired compound only in small quantity-the action of menthol on the ethyl ester in presence of hydrogen chloride was tried. A preliminary experiment indicated that alcohol was evolved in Considerable amount before the hydrogen chloride was introduced, and we afterwards prepared some quantity of menthyl acetoacetate by the action of heat on a mixture of menthol and ethyl acetoacetate, a method which afforded excellent results.Shortly afterwards, we found that Cohn had obtained the compound by this process (Mornatsh., 1900, 21, 200), but as he shortly after- wards notified that he had abandoned the work (Bar., 1900, 33, 734), with his concurrence we proceeded with the investigation. The ease with which the ester is prepared renders it possible to produce large quantities of it in a short time, and we propose to employ the compound as the starting point in the preparation of a number of other active compounds which may possess interest from various standpoints.1500 LAPWORTH AND HA”: OPTICAT,LY ACTIVE ESTERS OF Cohn does not state that he had formed any definite opinion as to the constitution of the solid ester which is obtained by this process.We are disposed t o believe that it must be the ketonic form, and for the following reasons, which, it must be admitted, are not altogether conclusive. The greater proportion of ethyl acetoacetate at the ordinary tempera- ture exists as the ketonic form (Trans., 1892, 61, 808). As a rule, compounds are stable in the enolic condition when they exhibit strongly acid properties, whereas the acidic properties of menthyl acetoacetate are exceeding weak, as is shown by the fact that it dissolves only very sparingly in cold alkalis, although these bring about equilibrium between the two forms very rapidly.Again, in the case of substituted acetoacetic esters, in which the substituent is not an acyl group, it is invariably the ketonic form which is the stable one. Lastly, there may be mentioned the behaviour of the compound towards ferric chloride, which indicates that the maximum quantity of enolic ester is not present a t the first moment of dissolution in a solvent. Menthyl acetoacetate exhibits mutarotation in non-oxygenated solvents, the change occurring with a speed which renders it easy to study the effects of agents with advantage. It is interesting to observe that hitherto only those types of com- pounds which have been shown by independent chemical or phyrsical methods to exhibit desmotropy or isodynamic isomerism possess the property of mutarotation, a fact which serves to support Lowry’s con- clusion (Trans., 1899, 75, 213) that the two phenomena are very closely related.Thus the compounds in which mutarotation has hitherto been observed with certainty are the aldoses and pentoses, nitro- and r-bromonitro-camphor, nitrocamphane, a-benzoylcamphor, cam phorquinonepb enyl hydrazone, and men thy1 acetoacetate, and in all these cases there is every reason t o believe that isodynamic change is the cause. I n the case OE many other active menthyl esters obtained from the formylacetate and acetoacetate, no observable change of rotation occurs, and this was t o be expected, as there is no suflicient reason t o suppose them capable of desmotropic change, although in some instances their constitutions are capable of two modes of representation, differing only in the position of a hydrogen atom.The most. striking feature of the mutarotation of menthyl aceto- acetate is the fact that traces of acids as well as of bases aczelerate the change, The significance of this observation is referred t o else- where (p. 1513) and need not again be discussed. Menthyl acetoacetate has apparently all the chemical characters of the ethyl ester, but exhibits certain qualitative differences, inasmuch as its reactions are more sluggish, requiring in most cases much longerP-KETONIC -4ND P-ALDEHYDIC ACIDS.PART 11. 1501 periods for their completion, A similar sl.uggishness is observed in the crystallising power of the higher substituted menthyl acetoacetates which we have recently obtained, for where the ethyl esters crystallise very readily, the menthyl esters tend to form jellies, or remain liquid for many weeks. R x P ERIM E NT AL. Preparation and Properties of Menthyl Acetoacetate. -Cohn (Monutsh., 1900, 21, ZOO) heated ethyl acetoacetate with menthol in a reflux apparatus at about 150' for 5 hours, and finally fractionated the pro- duct by distillation under diminished pressure. We prefer t o heat the materials in a Wurtz flask over an Argand burner, allowing the alcohol produced to distil OE as soon as it is formed, and, when the action be- comes very slow, t o boil off the unaltered menthol and ethyl acetoacetate under a pressure of about 15 mm., the distillation being interrupted when a thermometer immersed in the vapour indicates a temperature of about 1 6 0 O .The residue is poured into a beaker, and on cooling it slowly sets to a nearly solid mass, which is ground into a paste, freed from most of the oily matter by the aid of the pump, and finally washed in the funnel with a very small quantity of ether. The pro- duct so obtained forms a white, crystalline mass. It may be recrystal- lised by dissolving it in dry ether and cooling the solution by a freezing mixture. A further quantity of the substance may be obtained from the lower boiling portions of the distillate and the attendant oil by refractionation or by conversion into the copper derivative.By very slow crystallisation, the ester may be obtained in the form of large, transparent prisms, in which, however, there is very little tendency to the development of good end faces. Through some of the larger faces, which are usually very bright, a biaxial figure of very small angle may be observed in convergent polarised light, emerging obliquely to the field; the crystals appear to belong t o the monoclinic system, in which case the bisectrix is in the plane of symmetry. The double refraction is positive in sign and weak. The melting point of the compound is given by Cohn as 30--32O, which is the melting point we have usually observed, but on one or two occasions we have noticed that a small quantity of the material in a thin-walled capillary tube remained for a considerable time at 38-40° without melting, and if the temperature were raised somewhat rapidly, fusion did not occur until a temperature of 43-45O was reached.On cooling, no matter how long the material had been kept in the fused condition, rapid solidification always occurred, the whole setting to a mass of flat needles identical in crystalline character with the large prisms above described. The solid substance is probably the ketonic form of the ester, for1602 LAPWORTH AND .€€Ah": OPTICALLY ACTIVE ESTERS OF when it is dissolved in anhydrous ether, benzene, or chloroform, and a drop of an ethereal solution of ferric chloride is added, no marked coloration is developed unless the liquid is boiled or is allowed to remain for some time; a coloration is at once developed in the cold, however, if a trace of an organic base, such as pyridine, is previously added. Solutions in alcohol, immediately after preparation, gave with ferric chloride a faint coloration which rapidly deepened, whilst if the solution had been allowed to remain for a few minutes in the cold the maximum colour appeared to be produced at'once.A violet coloration is also produced when a drop of alcohol is added to the nearly colourless solution of the ester in benzene or ether containing ferric chloride. I n fact, the phenomena observed were very similar to those which we had noticed in the caw of menthyl formylphenylacetate, and, as in that case, all attempts to prepare the desmotropic form of the ester were unsuccessful.The specific rotation of the compound was determined in several solvents. I n 1.5 per cent. solution in absolute alcohol, it had [a], - 68.5'. I n ethyl acetate, its rotation at 1.5 per cent. concentration was [a]D - 59*8', and remained constant. I n these liquids, no very marked alteration of the specific rotation with time was noticed. Menthyl acetoacetate exhibits the phenomenon of mutarotation in aon-oxygenated solvents in a much more marked manner than does the formylphenylacetate. The change, moreover, appears to be much more rapid, and the velocity is greatly affected by the presence of catalytic agents, and varies cousiderably with the degree of purity of the solvent. In the cases cited below, we have employed media which have been subjected to careful purification.I n chloroform, an initial rotation of about [a], - 68.5' was observed, and in the course of some hours this had attained a constant value of -70.7". I n light petroleum, the rotation was initially [.ID 65*1°, and rapidly reached a maximum value of -74.4'. I n benzene, with which we have made most of our experiments, the rotation changed from about [a], -61.5' to -67.4' or -68.4' for concentrations between 1 and 2 per cent., the duration of measurable change varying from 20 minutes to 2 hours, depending, no doubt, on the purity of the specimen of solvent used. The effect of catalytic agents on the change could be conveniently studied in this instance, and we made numerous experiments on the point.The mode of procedure was similar to t h a t adopted in the case of camphorquinonehydrazone (this vol. , p. 15 17), a series of readings with three or more tubes containing the same solution being made simultaneously in every case. It was observed that, as usual, traces of all bases, including evenB-KETONIC AND B-ALDEHYDIC ACIDS. PART 11. 1503 weak tertiary bases, increase the velocity of change, and that traces of acids produce a similar effect. The acids tried included acetic, trichloro- acetic, benzoic, salicyclic, and crotonic acids, and were found to be effective even in minute quantities, particularly so in the case of the fitrongest one-trichloroacetic acid. I n this instance, too, it was found that marked acceleration was produced even by such weak bases as the monobromo- and mononitro- anilines, although the effect was distinctly smaller than when more powerful bases were used in equivalent quantities.The effects of various other substances' soluble in benzene were also examined, but hitherto only those compounds the effect of which might be ascribed t o acidic or basic properties have been found effective when added in minute amount : certain compounds, such as alcohol, produce very marked acceleration, but only when present in comparatively large quantities. As an instance of the sensitiveness of the compound toward acids, it may be mentioned that in one experiment four tubes were filled with the same solution of the ester in benzene; the initial rates of change of rotation in each mere measured and found to be nearly the same.Into t w o of these tubes traces of trichloroacetic acid were introduced by touching a moist crystal of the acid with a platinum wire which was then dipped into the solutions. I n the case of the two unopened tubes, the mutarotation continued t o be observable for more than an hour, whilst in the two others the maximum rotation was reached in less than ten minutes. Derivatives of Menthy2 Acetoacetale. With the exception of the copper compound, the metallic derivatives of the ester have not been obtained in characteristic forms. The com- pounds obtained by the action of amines and hydrazines on menthyl acetoacetate are, as a rule, easily isolated in a crystalline form. The phenylhydrazide has already been described by Cohn (Ber., 1900, The copper derivative, (C,,H,303),Cu, is precipitated as an oil on adding copper acetate dissolved in twenty times i t s weight of water to an alcoholic solution of the ester.When left in contact with the alccholic liquid, i t slowly becomes crystalline, and was purified by cry stailisation from hot alcohol. It separates almost completely from cold 90 per cent. ethyl alcohol in dark green, transparent prisms, which contain alcohol of crystallisation ; the latter is gradually lost when the substance is exposed to the air, the compound then forming a bluish-green powder. When heated rapidly, the crystals soften at 78-80", but do not melt below 106'; the dry substance, on the 33, 735.)1.504 LAPWORTH AND HA"; OPTICALLY ACTIVE ESTERS OF other hand, melts sharply at 117-118' and slowly decomposes.analysis : On 0.8139 gave 0.1173 CuO. Cu= 11.5. (C14H2303)2Cu requires Cu = 11 6 per cent, The sernicarbazide, NH,*CO*N,H,* C(CH,)~CH*CO,-C,,H,,, was made by adding semicarbazide hydrochloride dissolved in a little water to a solution of the ester in alcohol; on warming gently, the product separated rapidly as a paste of glistening, flat needles, and was crystal- lised from hot alcohol. On analysis : 0.1985 gave 0.4423 CO, and 0.1635 H,O. C,,H2703N3 requires C = 60.6 ; H = 9.0 per cent. It dissolves readily in benzene, acetone, ethyl acetate, or hot alcohol, somewhat less readily in ether, and is nearly insoluble in light petrol- eum. It crystallises from alcohol in small, flat needles, from ether in elongated plates, and melts a t 143-144'.A 1.5 per cent. solution in benzene had the rotation [a], - 56.1' and no mutarotation was observed. The crystals from ether are usually four-sided, rhomboidal plates, and on these the extinction directions in polarised light are inclined at varying angles to ths longer sides ; thsy frequently show a biaxial interference figure, the optic axis emerging neaxly perpendicular to the field. The p-nit.lo~~enyZhyd4.ccxide, NO,*C,H,*N,H,*C( CH3) :CH*CO,*C,oHIS, was prepared by heating together the requisite quantities of the ester and p-nitrophenylhydrazine in alcoholic solution for several hours on the water-bath and precipitating the product with water. The oily product, which did not show any sign of crystallising after some days, was fractionally extracted with cold light petroleum, when a consider- able proportion was obtained, on evaporation of the solvent, in a crystalline form.C = 60.7 ; H = 9.1. It was purified by recrystallisation from alcohol : 0.2275 gave 0.5320 CO, and 0.1626 H,O. C = 63.8 ; H = 7.9. C20H290,N, requires C = 64.0 ; H = 7.7 per cent. The hydrazide is readily soluble in warm alcohol and most of the usual media, but is only sparingly dissolved by light petroleum and is insoluble in water. It melts at 105-106'. A solution of 0.3533 gram in 25 C.C. of benzene gave [ u ] ~ - 42*5', no mutarotation being observable, even after addition of an acid or a base. The crystals from alcohol are transparent, brownish-yellow prisms or pyramids. When melted on a microscope slide beneath a cover- glass, the substance solidifies very slowly on cooling, forming small,,@-KETONIC AND ,&ALDEHYDIC ACIDS.PART 11. 1505 flat, isolated, four-sided plates, in which the extinction in polarised light is parallel to the smaller pair of sides. When the crystals are crushed and examined in convergent polarised light, many fragments show a biamial interference figure of wide angle. The double refraction is unusually strong. NH,*C( CH,): C H*C02*C,oH,,. - When ammonia is passed into menthyl acetoacetate at a temperature slightly above the melting point of the ester, it is only very slowly absorbed, and even after some dayathe action does not appear to be complete. If, however, a small quantity of ammonium acetate is introduced into the liquid, reaction occurs much more quickly, globules of water separate, and the whole finally sets to a semi-solid mass.I n order to purify the product, it was spread on porous earthenware and then crystallised Erom hot alcohol. Menthyl P-Arnirtocrotonate, On analysis : 0.2006 gave 0.5179 CO, and 0.1906 H,O. C = 70.4 ; H= 10.6. C14H2502N2 requires C = 70.3 ; H = 10.5 per cent. The compound dissolves fairly readily in most of the usual organic media and separates from alcohol on spontaneous evaporation in large, brilliant,, transparent prisms, with one good plane of cleavage. It melts at 88-89', and after solidification melts once more at the same temperature. A benzene solution containing 0.3895 gram of the substance in 25 C.C. of benzene was examined ; this gave [a], - 105.2', and no altera- tion of this value was observed.Small, elongated crystals of the compound are sometimes obtained ; these have straight extinction in polarised light, the directions of greatest length and elasticity being parallel. Crushed fragments of the crystals examined in convergent light frequently show a biaxial interference figure of moderate angle; this figure is probably that corresponding with the acute bieectrix ; the diqpersion is strong, the angle for red light being greater than that for blue. Menthy2 /3-Benxy Zaminocrotonate, C,H,*CH,* NH*C(C€€:,): CH*C02*C,oH1,. -A mixture of menthyl acetoacetate and benzylamine in molecular pro- portion was warmed gently until the solid had disappeared and was then allowed to remain at the ordinary temperature for some time.A milkiness, due to separation of water, soon became noticeable and at the end of six hours the whole was solid. The mass was dissolved in a little hot absolute alcohol and the crystalline separation purified by recrystallisation from absolute alcohol. On analysis : 002006 gave 0.5638 CO, and 0.1732 H,O. C = 76.7 ; H= 9.6 C2,H,,02N requires C = 76.6 ; H = 9.4 per cent. VOL. LXXXI. 5 11506 LAPWORTH AND HANN: OPTICALLY ACTIVE ESTERS OF The substance dissolves readily in benzene, chloroform, carbon tetra- chloride, ethyl acetate, acetone, or light petroleum, but is less readily dissolved by methyl or ethyl alcohol. It separates from hot absolute alcohol in flat needles and melts a t S5-86O. A solution containing 0.4032 gram in 25 C.C. of benzene gave [.ID -59.8O and this value remained constant, The crystals are elongated rectangular plates or flat needles, which show straight extinction in polarised light ; the directions of greatest length and elasticity are parallel. Menthyl p- Anilinocrotonnte, C,H,*N H*C( CH,): CH CO,* CloH19.- This compound was made by the interaction of aniline and menthyl acetoacetate in molecular proportion in the cold; the action is complete in 24 hours, and the product, which is somewhat oily, may be drained on porous earthenware and finally crystallised several times from methyl alcohol.On analysis : 0.2022 gave 0.5670 CO, and 0,1679 H,O. C=76*5 ; H ~ 9 . 2 . C,,H,,O,N requires C = 76.2 ; H = 9.2 per cent, It dissolves somewhat readily in most of the usual organic media and separates from methyl alcohol or absolute ethyl alcohol in thin plates or flat needles.It melts sharply a t 89-90', and after solidifica- tion fuses once more a t the same temperature, A solution containing 014045 gram in 25 C.C. in benzene gave [a], -98*2", and this value remained constant. The crystals from absolute alcohol are usually flat, rectangular plates which probably belong to the monoclinic system ; in polarised light, the extinction is straight and the directions of greatest length and elasticity are parallel. In convergent polarised light, the obtuse bisectrix of a bixial interference figure emerges through the larger face a t an angle inclined to the perpendicular; the axial plane is coincident with the plane of symmetry and the double refraction is moderately strong and negative in sign.When the substance is melted on a glass slide beneath the cover-slip, i t solidifies very slowly as the temperature falls, to masses of large, irregular plates identical in character with those above described. Action of Acid Ciiloyides on Xenthyl Acetoacetate and its Metallic Derivatiues.-Acetyl chloride acts slowly on the ester, hydrogen chloride being evolved, but nothing of definite character could be isolated from the product ; when, instead of the ester, the sodium or copper derivative is used, very rapid action occurs, but from the pro- duct nothing but the copper compound of the unaltered ester could be isolated. Unsatisfactory results were also obtained when attempts were made to prepare the 0-acetyl derivative from the ester by treat- ment with a mixture of acetyl chlaride and pyridine by Claisen's method.&KETONIC AND &ALDEHYDIC ACIDS.PART 11. 1507 More definite results were obtained by acting with benzoyl chloride on the sodium derivative of the ester suspended in ether. The action, which was apparently a slow one, was completed by the aid of heat and it should be mentioned that, even after several days' heating on the water-bath, no deposit of sodium chloride was observed, although the odour of the benzoyl chloride had entirely disappeared; we are un- able to offer any explanation of the fact. The ethereal solution was finally shaken with ice-cold water to remove sodium chloride and was then extracted repeatedly with a solution of sodium carbonate.On evaporation, the residual ethereal solution gave an oil which resisted all attempts at purification. From the sodium carbonate solution, however, an oil was deposited on acidification'; this was dissolved in alcohol and the solution treated with aqueous copper acetate, when a copious deposit of an insoluble copper derivative was obtained. The copper compound crystallised from hot ethyl acetate in slender needles of a greenish-blue colour. On analysis : 0,5053 gave 0-0527 CuO. Cu = 8.4. (C21H2704)2 Cu requires Cu = 8.4 per cent. The substance is sparingly-soluble in alcohol or cold ethyl acetate or acetone, but dissolves somewhat feadily in cold chloroform or benzene. When heated slowly, it darkens at 210--215O and melts and decomposes a t 226O, but if heated suddenly to 230' i t melts some degrees above this point.I n order to obtain the free ester, the copper compound was sus- pended in purified ether and shaken with dilute hydrochloric acid until the crystals had disappeared ; on evaporation of the washed and dried ethereal solution, a substance, which formed a very thick oil at the ordinary temperature was obtained. This decomposed when dist,illed under the lowest pressures which we were able to obtain, and was therefore dried at 100' and analysed : 0.23'75 gave 0.6358 CO, and 0.1802 H,O. The compound has therefore the composition, as well as the 'general properties of menthyl benzoylacetoacetate, COMe-CHBz*CO2*C,,Hl9, and is, in all probability, a mixture of the enolic and ketonic forms of that substance ; its alcoholic solution gave a deep brownish-purple solution with ethereal ferric chloride.A 25 per cent. solution of the compound in benzene gave [a]= -44.3' and this value remained constant during a week. In order to prove that a benzoyl group was present in the substance, it was cxidised with boiling alkaline permanganate solution and a con- siderable quantity of benzoic acid was obtained ; during the oxidation, a C=73.0; H=8-4. C,1H280, requires C = 73.2 ; H = 8.1 per cent. 5 1 21508 LAPWORTH AND HA”: powerful odour of menthol was observed. That the acetyl group was still present as well as the benzoyl group was evident from the strongly acidic properties of the compound, which dissolved readily in sodium carbonate solution. Menthyl acetoacetate reacts only slowly, if at all, with phenyl- carbimide; a mixture of 1 mol. of the latter with 2 mols. of the former remained unaltered in appearance during several months, and even after further heating on the water-bath retained the odour of the carbimide. The bromo-derivatives of the ester do not crystallise readily, nor do they appear to afford crystalline copper derivatives. The products obtained by the actioh of 1, 2 or 3 mols. of bromine on the ester were carefully examined, but in all cases they remained oily and afforded oily copper derivatives; no better results were obtained on attempting t o prepare the y-bromo-derivatives. The products obtained by the action of aldehydes and of diazonium compounds on the ester are a t present under examination. We pro- pose also to extend this study of optically active esters toactive esters of other ,&?-ketonic and P-aldehydic acids, and also to derivatives of menthyl cyanoaee tate. I n conclusion, me desire to express our thanks to the Research Fund Committee of the Chemical Society for a grant defraying much of the cost of this work. CHEMICAL DEPARTMENT, THE GOLDSMITHS’ INSTITUTE, NEW CROSS, S.E.

ISSN:0368-1645    

DOI:10.1039/CT9028101499

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1508 LAPWORTH AND HA”: CXLIX.- The Mutcrrotation of Camphorquinonehydr- axone and Mechanism of Simple Desmotropic Change. By ARTHUI~ LAPWORTH and A. C. OSBORN HANN. OF the various types of isomeric change, that which involves a change of position of one hydrogen atom only, as in a simple desmo- tropic change, would, for various reasons, appear to be the most simple, and probably the most easy to investigate. We do not intend to review the many important contributions already made to this subject, in particular since such a course would involve, for the most part, a repetition of much with which Lowry has somemhat recently dealt in his suggestive paper on mutarotation andTHE MUTAROTATION OF CAMPHORQUINONEHYDRAZONE. 1509 reversible isodynamic change (Trans., 1899, 75, z l l ) , but a brief reference to some views which have already been advanced appears desirable.Perhaps the theory most commonly used with regard to the mechan- ism of reversible desmotropic transformations is that which assumes an alternate addition and elimination of the elements of water or of some other hydrogen compound in the following way : H,O+:C=&OH f-, : c H - ~ < ~ ~ OH +-+ :CH-*=O+H,O or Lowry (Trans., 1899, 75, 221) has assumed that in the acceleration which is almost invariably effected by bases the first change con- sists in the formation, in the case of a nitro-compound, of a salt of the iso.form, in this way : NaOEt + :CH*NO, -+ :C:NO*ONa + HOEt, and that the interaction of this compound with water or alcohol leads, on the one hand, to the free iso-form, and on the other, to the free normal form of the nitro-compound. This view possesses distinct ad- vantages over the foregoing one, but appears to disregard certain very important points.Laar’s theory (Bey., 1885, 18, 648), which involves the conception of a free hydrogen atom vibrating continuously between the two different positions of attachment, was not put forward to explain the occurrence of desmotropic change, and, in fact, the reasons for its advancement can no longer be said to exist. It need not, therefore, be taken into consideration a t present, although it bears a superficial resemblance to certain views which appear later in this paper. An altogether different view of the change of enols into ketones has been advanced by Bruhl (Sei-., 1899, 32, 2329), who has found that the velocity of the conversion of ethyl mesityloxideoxalate from the enolic into the ketonic form is closely related to the dielectric constant of the medium, and in such a manner as to support his prediction that the influence of the medium would be found to be a function of its ionising power.Briihl’s view of the change may be expressed briefly as follows. The enols are hydroxylic substances, weak acids, and electrolytes, and dissociate into hydrogen ions and a residue :C:d-O-; these residues have a tendency to reunite with hydrogen ions t o form a non-ionised compound of a ketonic type, :CH*k = 0. This view, if correct, contains, we venture to beIieve, the elements of a real explanation, lending itself t o experiment and development in1510 LAPWORTH AND HANN : a way which the others can scarcely be said to do, and provides, more- over, a means of ascertaining what is the probable part played by traces of catalytic agents in accelerating the velocity of change. Although it may always remain a matter of opinion whether the presence of catalytic agents is absolutely essential in effecting changes which, in their absence, do not progress with measurable velocities, it is generally recognised that it is difficult to overestimate the im- portance which m%y be attached to their influence, as Armstrong in particular has repeatedly insisted.It appears, therefore, not unlikely that a study of the induence of traces of different agents in accelerat- ing or retarding a change may be found to serve as one of the most satisfactory bases on which to form useful views of the mechanism of the change.Bruhl’s view, as above stated, is, however, by no means complete, as in many cases the enolic forms do not become completely converted into the ketonic forms, although the latter have no measurable conductivity, but in solution a state of equilibrium between measurable amounts of the two forms is finally reached. From the standpoint of a theory of isomeric change which involves the assumption of ionisation, there can scarcely be chosen a more suitable case of change for investigation than that in which the migrating part is a hydrogen atom, since there can be little or no doubt with regard to the charge of the migratory ion, whereas in the majority of other cases this difficulty is a very real one.Assuming, then, the broad principles of Briihl’s suggestion as altogether reasonable, it is a t least worth while endeavouring to discover to what they may lead, With respect to the transformation of the ketone to the enol, the condition of equilibrium between isodynamic forms is not disturbed by the presence of traces of impurities, a statement which is supported both by thermodynamic principles and by direct experiment, even though the impurities may be present in amount sufficient to acceler- ate very greatly the velocity with which the position of equilibrium is attained (compare Lowry, Zoc. cit., 222, 243). Hence any agent which affects the velocity of either change must affect the reverse one in the same manner, and in the case under consideration it seems difhult to avoid the conclusion that in the change of ketone to enol the same type of process must go on under any set of conditions as in the reverse one, that is to say that these compounds are also ionised to a minute, although quite immeasurable, extent, affording hydrogen ions.We thus arrive a t a view similar in a sense to those of Thiele (AnnaZen, 1899, 306, Il4), Henrich (Bey., 1898, 31, 2103), and others who regard the hydrogen of the group X = Y - ZH as ‘‘ directly replaceable,” and Vorliinder has pointedTHE MUTAROTATION OF CAMPHORQUINONEHYDRAZONE. 15 11 out that the grouping mentioned is characteristic of acids (Bey., 1901, 34, 1633). It must therefore be inferred from Briihl’s view that the mutual and spontaneous interconversion is to be represented as the result of the processes -t- X=Y-ZH ++ X=Y-Z+H ++ XH-Y=Z; but it would appear from this that the velocity of change should be simply dependent on the number of times per second that the hydrogen ions come in contact with the negative ions or “residues.” This would be proportional both to the concentration of the hydrogen ions and to that of the negative ions, and therefore to the product of these concentrations.This product, however, in any solvent, bears a constant ratio to the concentration of the undissociated part of the substance, hence the addition of a trace of an agent which only altered this ratio, as, for example, an acid or a base, should produce no marked alteration of the velocity. Or, representing the concentration of the individuals in the above scheme in order as c,, c2, cQ, c4, and the velocities as k,, Z1, kr2, k2, we have dc, = c2c3k, - c&’, and ’% = ~ 2 ~ 3 k 9 , - c4kt2 dt d t hence the rate of change from, say, undissociated enol to ketone is that is to say, a velocity which is of the same order as that of the ionisation, and therefore for an enol of measurable conductivity (where at least we are probably justified in assuming a practically instantaneous ionisation) very great.Again, addition of a small quantity of an acid or base does not alter ~ 2 ~ 3 , and produces no appreciable effect on c1 or c4, the concentration of the undissociated parts of the enol and ketone. Further, in equilibrium we should have dc 3 = 0 = -4 or c2c3k1 = clZl and cacsk‘2 = c4k2 ; dt dt hence 5 = ($)@) = $ or the ratio of the concentration of 04 the t,wo forms would be equal to the inverse ratio of their dissociation constants.Thus, when one form is a conductor and the other is not, the former would not be preseut in appreciable amount, a result which is altogether at variance with what is known of the facts. Some other time factor must therefore be involved, probably small in com-I512 LAPWORTH AND HA": parison with those above considered, and it seems obvious that this must be connected with the internal change of structure which the molecules undergo during mutual interconversion. I n our opinion, this velocity is best introduced in accordance with the suggestion already made by one of us (Trans., 1901, 79, 1266) that the internal change takes place only in the ion, and simply resuIts in a move- ment of the position of '' free affinity." Introducing this, we have the following scheme to represent the changes occurring : X:Y*ZH t-, X:Y*Z- +H x:y*z- .f-, -x*y:z -X*Y:Z+H t-, XH*Y:Z Here the velocity of change will be proportional to the absolute Concentration of the organic ion and will of course be increased as the concentration of the hydrogen ions is diminished and vice uersb.It is not difficult to show that it will be inversely proportional to the concentration of the hydrogen ions, and this is consistent with the properties of many organic compounds. Indicating the concentration of the second organic ion by c5 and the two new velocities introduced as k, and k', respectively, we should have in equilibrium Hence or, the ratio of the concentrations of the two forms is independent of the concentration of the hydrogen ions and therefore unaffected by catalytic agents, but is inversely proportional to the respective veloci- ties of internal rearrangement and also to the dissociation constants.It follows from the latter that where a measurable amount of conduct- ing enol is in equilibrium with an apparently non-conducting ketone, the ion of the latter is transformed into that of the former with a velocity which is very great in comparison with the reverse change. The conclusions to which the foregoing view leads are in accordance with the behaviour of certain isodynamic pairs of this kind. Thus, Lowry has found that the conversion of nitrocamphor into the &o- nitro-form is accelerated by bases but not by acids (Zoc.cit., p. 221) ; he has not stated however, whether any retardation was observed, whereas we find that in the case of camphorquinonehydrazone it is apparently possible to arrest the isomeric change a t any stage by the introduction of a trace of an acid. Moreover, it appears to be a very general rule that bases of all types accelerate the change, so that inTHE MUTAROTATION OF CAMPHORQUINONEHYDRAZONE. 1513 most cases the foregoing process may play an important part. Never- theless, there are other cases where, on the contrary, acids may accelerate the change. Thus, in converting dibenzoylmethane into the corresponding enolic form acids are used (Annalen, 1899, 308, 219j, and Forster found that formic acid was the most effective solvent in transforming enolic benzoylcamphor into the ketonic form (Trans 1901, 70, 997).These facts might possibly be explained rather as the result of the retarding influence of the acids on the mixture in a state of equilibrium preventing the reversion of the usually more unstable form as crystallisation occurred. No such ambiguity, however, exists in the case of menthyl acetoacetate which the authors have recently had under examination. Here a trace of an acid accelerates the change very greatly, hence it appears that in some cases a t least a new factor must be taken into account. One of the authors has already suggested (Proc., 1901, 17, 95) that hydrogen ions may themselves causg the change by forming complex ions with the compounds : in other words, that the latter may act as feeble bases.I n this case, as in the previous one, the process involves a structural change, and this change, as before, may be conventiooally introduced by making the assumption that the organic ions in the two cases are not identical but are mutually interconvertible by a simple internal rearrangement. The imaginary process is easy to understand by reference to a model, but it is not so easy to represent as that in the previous case. However, it may be expressed as XH-Y=Z+H t+ XH-YTZH XH-YTZK ++ XH;-Y=ZH, XHYY-ZH ++ XY-ZH+H where the dot indicates the direstion in which the ‘ I free affinity ” of Y is temporarily disposed. Here, as before, the velocity of change will be proportional to the concentration of the organic ion if the ionisation velocities are very rapid in comparison with the speed of structural change, aria there- fore proportional to the concentration of the hydrogen ions, It is thus possible that a desmotropic or tautomeric change may be the result of one or both of two superposed reactions, one due to ion- isation in the compound itself, accelerated by bases and retarded by acids and the other due to an additive phenomenon, accelerated by acids and retarded by bases.Both reactions in compounds which are not associated will be unimoleeular in type where the concentration of the hydrogen ions does not vary, as will also be the velocity obtained by their superposition. That the two actions are different in kind appears to be shown by the fact that compounds which are not1514 LAPWORTH AND HA": very different in their susceptibility to bases may be altogether different i n their behaviour towards acids.How far such views as these may bear the test of further investi- gation remains to be seen, but i t will certainly be interesting toascer- fain whether some isomeric changes of other types may not be explain- able by the aid of similar views. Clearly two types of catalytic agents at least may be sought for, one type acting by diminishing the concentration of ions representing the labile group without altogether removing it, the second increasing the concentration of these ions and effecting the change by a process which may be regarded as one of addition. EXPERIMENTAL.Desrnoh-opic Forms of C a m p ~ o r ~ u i n c n e h d ~ ~ z ~ e . Camphorquinonehydrazone may be prepared by two methods, namely, by the action of phenylhydrazine on camphorquinone or by the action of diazobenzene on camphorcarboxylic acid. Betti has found (Ber., 1899, 32, 1995) that the partially purified material ob- tained in the latter process melts indefinitely at temperatures varying between 154' and 1 6 5 O , but when purified by crystallisation from hot alcohol or from benzene and petroleum at 178-180'. We have obtained exactly similar results when preparing the substance from camphorquinone and phenylhydrazine. The melting point of the most highly purified material obtained was about 180-181', a melting point practically identical with that given by Betti.On analysis : 0.2824 gave 0*7790 CO, and 0,2099 H,O. C = 75.2 ; H = 8.2. C,6H2,0N, requires C = 75.0 ; H = 7.8 per cent. The substance obtained from alcohol and melting at 180-18lo presents all the appearance of a uniform substance to the naked eye, and under the microscope is seen to consist entirely of small, well-defined plates which are apparently hemihedral in character, being usually pointed' at one end and truncated a t right angles to their length at the other; from some other solvents, as, for example, benzene, it frequently separates in well-formed, flattened prisms. There is, in fact, every reason for regarding the material as a simple substance, free from any appreciable quantity of a second compound. Under certain conditions specified by Betti (Zoc.cit., p. 1998), a mixture of two compounds is obtained, notably when the material is precipitated from alcohol by means of alkalis, or when the substance of high melting point is kept for a short time in a fused state. The product then usually melts at about 1 6 5 O , and no longer presents the appearance of a pure compound, and the melting point is somewhatTHE MUTAROTATION OF CAMPHORQUINONEHYDRAZONE. 1515 indefinite. Similar mixtures are frequently deposited from hot benzene. Betti describes a third substance which separated when piperidine was added to the solution of the compound in benzene; he states that it separates a t once in small crystals and melts at 1 5 5 O , and regards it as a uniform substance as it differs from either of the fore- going materials in affording no appreciable coloration with ferric chloride in benzene solution.It is in this particular alone that we have not been able to confirm Betti’s results, as we have not succeeded in isolating a uniform substance other thnn that melting at 180°, although we have obtained specimens of material which melted at temperatures not far removed from 1 5 5 O . For various reasons, which will be indicated later, we believe that the process used by Betti and based on the mistaken view of Schiff (Re?.., 1898, 31, 601), that piperidine favours the production of the ketonic form, would actually tend to be disastrous so far as the isolation of the usually more elusive member of such a desmotropic pair is concerned. As the substance meeting at 180°, when dissolved in dry benzene, gives a reddish coloration on addition of an ethereal solution of ferric chloride which is not noticed when the material of lowest melting point is employed, it would appear that there is no fault to be found with Betti’s conclusion that it probably represents the pure enolic form C*H,,<8.C*N:NPh. *H This coloration, however, is never intense when the pure compound is used, although a small quantity of some un- known impurity occasionally renders it s o ; it is, in fact, easily masked by the yellow colour of the solution OF the pure enol, or by that of the ferric chloride when this substance is used in too large amount. For these reasons we think that it is possible to attach undue importance to the apparent non-production of the coloration with the material of low melting point.Mzcturotation of Camp~orpwinonehydru~one, AS was to be expected, the hydrazone in certain solvents exhibits the phenomenon of mutarotation (Lowry, Trans., 1899, 75, 211), due, no doubt, to isodynamic change as in the other cases. It is unfor- tunate that many of our experiments lose some of their value as it was not possible to extend them to both of the pure desmotropic forms, but certain interesting conclusions may be safely drawn from them, and they have at least helped to render it certain that piperidine assists only in establishing equilibrium between the two forms, and does not favour the existence of either form, as Betti’s conclusion would appear to assume. Observations of the rotatory power of the compound in alcohol1516 LAPWORTH AND HA": showed that mutarotation could not be detected in this solvent, either when the pure enolic form or mixtures of low melting point were used; in both cases the rotation of 1 per cent.solutions immediately after making up was [ a ] , +436* to +440°, hence i t would seem that equilibrium is here attained very rapidly. I n ethyl acetate, a t 1 per cent. concentration, the initial rotation was [.ID +405O, and fell rapidly to about + 380". I n benzene, which me have found t o be the solvent in which the mutarotation is most easily followed, the initial rotation of the pure enolic form was about [a], + 320' t o 325O, and fell slowlytovalueswhich varied widely with the concentration. When the original rotation in a 2 dcm. tube was 2*81', it fell in less than two days to a constant value, 2*62', whilst when the rotation was initially 0*98O it fell t o 0.53' in about the same time ; in an extreme case a solution having originally a rotation of 0.38' gave finally the number 0.13'.Thus the ratio of the initial and final rotation varies from about 1.1 in 0.5 per cent. solution to nearly 3 in 0.1 per cent. solution, We have noticed that, when the change is going on, the solution usually becomes darker in colour, but this is not invariably the case. Lowry has observed a somewhat similar effect with nitrocamphor (Trans , 1899, 75, 2). It is unfortunate that it cannot be determined whether the curves represent uni- or bi-molecular changes, as it is impossible to calculate even approximately the actual proportion of ketone and enol present.I n making up solutions in benzene, we met with considerable difficulty in determining the exact initial specific rotations, for owing to the fact that the material dissolved very slowly in cold liquids, attempts to bring weighed quantities rapidly and completely into solution were unsuccessful, so that by the time we were able to observe the rotation this had already fallen appreciably. We were therefore compelled to resort t o the method of shaking the substance with the solvent for a short time, filtering from undissolved matter, and reading a t once, afterwards estimating the amount dissolved by evaporaking a known volume t o dryness. Such a process, how- ever, was not very accurate, and also involved waste of carefully purified material. The somewhat remarkable variations of the final specific rotatory power of the solution with dilution would be explained if tha enolic form were largely polymolecular in benzene solution, or if the specific rotatory power of the ketonic form varied greatly with the dilution.As a determination of the moIecular weight of the enolic form in benzene by the cryoscopic method made as soon as possible after solution indicated that the solution had a normal molecular weight, the second view appeared to be the correct one, and received confirmation from the following facts,THE MUTAROTATION OF CAMPHORQUINONERYDRAZONE. 151 7 A strong solution of the enolic form in benzene was left until it showed a constant rotation, which required about 40 hours.A measured pdrtion of the solution was then diluted to a known bulk with benzene and the rotatory power of the resulting solution at once measured ; the number obtained was much lower than that calculated by multiplying the number for the original solution by the ratioof the concentrations in the two cases, and agreed fairly well with the number which had been obtained as the final rotatory power in a solution of similar concentration ; moreover, no mutarotation was noticed. Several experiments of this kind were made, and in every case similar results were obtained. It would therefore appear that the ratio of concentra- tion of the two forms when in equilibrium in benzene solution is nearly independent of the concentration. Having prepared various specimens of material of low melting point by various methods, inclucting that recommended by Betti as leading to the production of the pure ketonic form, it was thought that an examination of their behaviour in benzene solution would finally decide the question whether they were really composed largely of the enolic form, for had this been the case there was every reason to believe that their rotation in benzene would have been lower than that of material which contained both forms in equilibrium, and that a rise with time would be observable.As a matter of fact, it was found in every case that in dilute solution a very considerable fall instead of a rise occurred, and we conclude that our materiais, a t least, have always contained a considerable proportion of the enolic form.Efect of Catalytic Agents on the Mutarotation,. I n determining how traces of catalytic agents affect the speed of change, no attempts were made to obtain solutions of known concentra- tion; usually, about a gram of the pure hydrazone melting a t 180° was shaken for a short time with 100 C.C. of benzene, and the solution filtered and distributed between several tubes. The initial velocities of mutarotation in the various tubes were determined by a series of observations with each. Traces of different materials were then introduced into some of the tubes and the subsequent rate of change determined as before. By plotting the results graphically, any sudden alterations could easily be detected, although this was usually un- necessary, the effect of the agents where they were efficient being at once obvious. (u) Efeot of Buses.-It is well known that the hydroxides and ethoxides of sodium and potassium, and primary and secondary organic bases are usually effective in promoting the attainment of equilibrium between tautomeric forms, andt in this case also traces of sodium1518 LAPWORTE AND HA"; ethoxide, ammonia, aniline, and piperidine accelerate the change of rotation in benzene solution in a very marked mahner; the nitro- anilines, in very small quantities, produced very little effect.When solutions in alcohol, which exhibited no mutarotation, were used, the agents did not appreciably alter the rotation, 'so that it seems fairly clear that equilibrium is reached almost immediately in this medium. It is frequently assumed that these bases act by a process of addition in the manner indicated in the introductory part of this paper ; experiments with a number of tertiary bases where addition in that sense is impossible were therefore undertaken, and it was found that these acted precisely as did the others, traces of trimethylamine, pyridine, strychnine, and brucine bringing about a great acceleration, although the amounts of the two alkaloids used were too small t o be detected by the polarimeter.As was only to be expected, the final rotations of the solutions were always independent of the speed with which the change occurred and of the catalytic agent, the differences between the rotations of the same solution in two or more tubes being of an order which was not greater than that probably due to experimental error.(6) E'eeqt of Acids.-It does not appear that any careful experiments on the influence of acids on the speed of tautomeric change have been made. As this point appears to us of the utmost importance in connection with the question of the mechanism of the change, we have devoted a considerable amount of attention to it. I n all instances we have found that the mutarotation i's retarded by acids, whether these are present in mere traces or fairly large amounts; moreover, there is a certain amount of evidence that the retardation is dependent on the strength of the acid : thus a set of tubes were filled with the same solution, and the curves of mutarotation traced by a number of readings and found to be very similar ; approximately equivalent quantities of acetic acid and of trichloroscetic acid were introduced into two of these by adding one drop of highly dilute equivalent solutions of the two acids in benzene, mixing, and taking a new set of readings.A very distinct retardation was noticed with the former, but in the case of the trichloroacetic acid the subsequent mutarotation was too slow to be detected during the course of ten days; the solution containing acetic acid had by that time fallen to a constant value, whilst the solution which did not contain any impurity had shown a constant rotation after thirty hours. The apparently complete arrest wbicb could be effected by a trace of a strong acid can most easily be shown by dipping a platinum wire into trichloroacetic acid, and then into a solution of the hydrazone contained in the cibservation tube.Small quantities of benzoic, salicylic, and several other acids produced Pimilar effects,THE MUTAROTATION OF CAMPHORQUXNONEHYDRAZONE. 1519 It may be noted that by adding a trace of a base to the solution, the mutarotation of which has been arrested, it is possible, with care, to cause it to proceed slowly once more and to arrest it a second time. The final rotation of the solution is of course independent of this treatment. Conclusion. Betti found that the material melting a t 155O, and which is supposed to be the pure ketonic form, could be reerystallised from benzene without change, providing that a trace of piperidine were present, Now it is cIear,from the above observations that bases bring about the equilibrium between the two forms, so that, even if Betti’s supposition were oorrect, it would seem that the presence of piperidine in the solution would not tend to preserve the ketonic form, but the reverse, and the presence of an acid rather than a base would probably be desirable. I n a benzene solution of the two forms in equilibrium, the solution might be nearly concentrated for both, and on cooling a srnaIl quantity of either form alone might separate, when the equilibrium would be momentarily upset. In presence of a sufficient quantity of a base, the result would be the immediate formation and separation of more of this form, and so on, whilst in the absence of an accelerator, a mixture of both would naturally be obtained. The isolation of the pure ketonic form might thus depend on the initial accidental presence of a minute quantity of that form in the solid state, and it is possible that we have been unfortunate in this respect. Nevertheless, on carefully reviewing the whole of the evidence, we cannot but regard Betti’s conclusion as to the nature of the compound melting a t 155O with much suspicion. However, the following possibility still presents itself. We have to express our cordial thanks to Signor Betti for most cour- teously acceding to our request that we might undertake this in- vestigation, as well as for giving us all the assistance in his power. Our thanks are also due to the Research Fund Committiee of the Chemical Society for a grant which helped t o defray the cost of the materials required in the investigation. CHEMICAL DEPARTMENT, GOLDSMITHS’ INSTITUTE, NEW CROSS, 8.E.

ISSN:0368-1645    

DOI:10.1039/CT9028101508

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1520 TITHERLEY: THE ACTION OF SODAMIDE AND OF CL.-T%e Action o f Xodamide and o f Acyl-substituted Sodamides on Organic Esters. By ARTHUR WALSH TITHERLEY, D.Sc., Ph.D. THE marked reactivity of sodamide with most cIasses of compounds and the peculiar nature of the results in many cases has rendered the study of its behaviour with organic substances of considerable importance. The author has already shown (Trans., 1897, 71, 462) that with substances containing the NH, or NH group, the hydrogen atom becomes replaced by sodium on treatment with sodamide if the neighbouring group possesses even only a very weak negative character, ammonia being at the same time produced. Thus all amides readily give rise to sodium derivatives of the type R*CO*NHNa or (R-CO),NNa, which are conveniently looked upon as subptituted (acyl) sodamides.The behnviour of the latter, and of sodamide itself, with alkyl and acyl haloids, as well as with potassium alkyl sulphates, has already been described (Zoc. cit.). The behaviour of sodamide with ester, when first examined, presented some anomalous features which made it clear that esters of the aliphatic or phenyl aliphatic acids behaved differently from those of true aromatic acids like ethyl benzoate. It was found that the former, owing to the enolic tendency present in the grouping -CH,*CO-, reacted with sodamide, giving rise, with formation of ammonia, to condensation products similar to those obtained by means of sodium ethoxide. When the interaction of sodamide and an ester was carried out carefully in the cold in presence of pure, dry benzene, there was at first practically no evolution of ammonia ; a white, insoluble, flocculent powder, however, slowly separated which was very unstable and readily evolved the gas.This solid, which appears to be formed as an intermediate product in all the ester reactions, is probably an /OR additive compound containing the group -CLNHz; but owing t o \ONa its instability, no reliable means of ascertaining its nature could be obtained by analysis or otherwise. Such intermediate products were formed in the case, for example, of the action of sodamide on esters of acetic, oxalic, and benzoic acids, but by allowing the action to proceed further, results of a very different kind were obtained in these three typical instances. Before attempting to elucidate the general nature of the reaction between sodamide and the group -CO*OR, the behaviour of this substance with simple ketonic compounds was studied.Acetone wasACYL-SUBSTITUTED SODAMIDES ON ORGANIC ESTERS. 1521 selected for the purpose, but, like the aliphatic ketones generally, it was found to behave quite differently from purely aromatic ketones ; thus whilst it reacts with sodamide with great energy in benzene solution, benzophenone under similar circumstances is quite unaffected. Here, as with aliphatic esters, the enolic tendency in acetone, and not the simple CO group, is responsible for the action. The change is almost entirely one of condensation, and the ultimate result of whatever reactions occur is the withdrawal of the elements of water, which a t once decomposes more sodamide, liberating ammonia.Mesityl oxide, phorone, and isophorone are the chief products formed. The interaction of sodamide and ethyl acetate, which was chosen for study as a typical ester, was examined under a variety of conditions, but in all cases it was evident that the chemical change could not be confined to a simple action between the carbethoxyl group and sodamide. When the ester is allowed to act in well-diluted benzene solution on finely powdered sodamide, the whole being kept cool, a white, flocculent precipitate is formed, which is very unstable, readily giving off ammonia, and is presumably an additive product as already conjectured. I f the mixture is allowed to stand, or is warmed, a vigorous action sets in and a white or yellowish-white solid separates.This solid is essentially ethyl sodacetoacetate, from which it appears that the ultimate action of sodamide is similar t o that of sodium ethoxide. The action may be expressed thus : 2CH3*C0,Et + ZNaNH, = CH,=C(ONa):CH-CO,Et + aNH, + NaOEt. A small quantity of sodium acetamide and a considerable quantity oE sodium acetate are also formed owing to secondary reactions. The production of sodium acetate is not easy to explain. With all esters the action of which with sodamide has been examined, it has been found that the group COOOR becomes CO*ONa to a greater or less extent (as a bye-product), even when moisture is rigidly excluded. There can be no doubt ‘that the sodium ethoxide formed as one of the products of all these reactions exerts a saponifying influence, even in presence of benzene.Geuther (Jahresber., 1868, 513) has shown that sodium ethoxide is readily capable of saponifying ethyl benzoate, forming sodium benzoate and ethyl ether, among other products, on heating. By the action of sodamide on esters of formic acid, large quantities of sodium formate are produced. This was observed with ethyl, butyl, and amyl formates, all of which react vigorously, giviug off ammonia even when well cooled or diluted with benzene. Sodium forniamide and formate are formed in large quantities as thick, white, solid products. HCO-OR + 3NnNH, = HCO*NHNa + NaOR + NH,. One of the changes which occurs is therefore simply VOL. LXXXI S K1522 TITHERLEY: THE ACTION OF SODAMIDE AND OF No evidence whatever could be obtained of the replacement of the hydrogen atom in these formic esters by sodium giving derivatives of the type Na*C10*OR (compare Freer and Sherman, Amer. Chem.J., 1896, 18, 7). As the behaviour of ethyl acetate and other fatty esters threw no light on the nature of the action between the carbethoxyl group itself and sodamide, ethyl benzoate was selected as a convenient ester for $his purpose. I t s action with sodamide is much less vigorous, and in benzene solution in the cold the formation of the white, flocculent additive compound is very slow indeed. When the mixture is gently warmed, ammonia is gradually disengaged and a white, gelatinous solid separates, which slowly turns yellow and consists essentially of sodium benzamide and sodium ethoxide, but also contains sodium benzoate, the relative proportions of these products varying with the proportions of ethyl benzoate and sodamide taken.Similar observations, made with other ethyl esters in which there was no enolic tendency, serve to show that, under suitable conditions, the carbethoxyl group reacts with sodamide, yielding acyl-substituted sodamides according to the general equation : R*CO*OEt + 2NaNH, = R*CO*NHNa + NaOEt + NIT,. Phenyl esters, on the other hand, appear to behave quite differently. As yet, only the action of phenyl acetate and of phenyl benzoate on sodamide has been studied. The former behaves like the ethyl ester, but the latter has an entirely different action, for instead of sodium benznmide, which is not formed, sodium dibenzamide is obtained in large quantity along with sodium phenoxide and ammonia.The action, moreover, is completed more quickly and is attended with practically none of the secondary decompositions which occur during experiments with the ethyl ester. The change may be expressed thus : Ph*Co*oPh Ph-CO*OPh + :>"a = (Ph*CO),NNa + 2PhOH. It is far more probable, however, that the reaction occurs in two stages; in the first of these, an intermediate additive compound is formed, which in the second is almost immediately acted on by a mol. of the ester. The phenol formed a t once liberates ammonia from the sodamide present : NaNH, /OPh Ph*CO*OPh - +- Ph*C-NH, + PhO*CO*Ph + \ONa PhG(ONa):N*COPh + 2PhOH.ACYL-SUBSTITUTED SODAMIDES OX ORGANIC ESTERS.1,523 I n this equation, the sodium compound, derived from the tautomeric form of dibenzamide, is represented as the product, as its stability in aqueous solution suggests the hydroxy-structure, free dibenzamide being a non-dissociated, perfectly neutral substance, like the pseudo- acids of Hantzsch. On similar lines, the production of sodium benzamide in the ethyl ester experiments probably occurs through the removal of a mol. of alcohol from the additive compound /OEt NH \ O N a Ph C-NH, -+ Ph'CCONa + EtOH, in which the sodium derivative of the iminohydroxy compound results. It has, however, not been found possible to prove this (see Trans., 1901, 79, 407). When the action of potassium alkylsulphates on sodium dibenz- amide, prepared from sodium ethoxide and dibenzamide in pres=.nce of alcohol, was examined, the results were found to be anomalous, as the expected alkyl derivative, (C,H,*CO),NR, was not obtained.Primary acyl sodamides readily allow replacement of sodium by an alkyl group under these conditions, as has been already pointed out (Trans., 1901, 79, 400). From among the products of the reaction bet ween sodium dibenzamide and potassium ethylsulphate, three substances were isolated, namely, benzamide, benzethylamide, and ethyl benzoate, but no ethyl dibenzamide. A small quantity of benzonitrile was also formed, and when the sodium dibenzamide was prepared from sodamide (that is, in absence of alcohol), the nitrile and ester were the chief products. The reaction in the latter case can be expressed by the equation 2g;:gg>"a + C,H,K*SO, -+ C,H,*CO*OC,H, + C,I€,.CN + NaKSO,. As this behaviour is very curious, the experiments were repeated under varying conditions.I n one set, potassium ethylsulphate and sodium dibenzamide, in molecular proportion were dissolved in the minimum quantity of alcohol, and after removal of the bulk of the latter the mixture was carefully .heated and distilled, whereby' a yellowish oil was obtained. From this oil, some needles of dibenzamide separated, and after removing these and fractionating, a liquid boiling between 190' and 215' came over, from which ethyl benzoate and some benzonitrile Mere isolated. At higher temperatures, an oil came over, boiling between 290' and 300°, which, on standing, mostly solidified in the form of rectangular plates ; these, after recrystallisation, melted a t 5 K 21524 TITEERLEP: THE ACTION OF SODAMIDE AND OF 69.5' and consisted of benzethylamide, C,H,*CO*NH*C2H5.Some benz- amide was also isolated. On repeating this Hxperiment, without distilling but simply heating in a bath at ZOOo, and afterwards treating the mass with water and extracting with ether, a much larger quantity of benzamide was obtained. Only a little benzethylamide was apparently formed in thi! case, and in neither experiment could any ethyldibenzamide, ( C,H5*C0)2N*C,H,, be isolated. Similar results were obtained in experiments in which potassium methylsulphate was used. Lastly, the action of potassium ethylsulphate on sodium diacetamide was examined, the latter being prepared from sodium ethoxide and diacetamide in alcoholic solution.After removal of the alcohol, the mixture was gently heated and distilled. The distillate, on fractiona- tion, gave essentially two products, one boiling a t about SO", which was ethyl acetate (with a little acetonitrile), and the other, boiling at 2 2 2 O , as an oil which quickly set t o a crystalline mass of acetamide, melting after recrystallisation at 81". There was no indication of the formation of ethyldiacetamide. The cause of these abnormal relations was traced to the influence of the alcohol present, although, as previously shown (Zoc. eit.), it does not interfere in the action between potassium alkylsulphates and the sodium derivatives of primary amides. In the case of secondary amides, on the other hand, such as dibenzamide, i t appeared on investi- gation that their sodium derivatives, although perfectly stable in alcoholic, and usually even in aqueous, solution, suffer a change on heat- ing with alcohol at about 16OC, which may be represented by the revernible system : d c The change is probably much more complex in reality and is occasioned by the presence of sodium ethoxide which, to some small extent, must be present in equilibrium with sodium dibenzamide in an alcoholic solution of t h i s substance.If sodium ethoxide dissolved in alcohol is treated with dibenzamide in about equivalent proportion, the latter dissolves on warming, forming a clear solution of the sodium derivative. This solution remains clear for some time, but on keeping hot it suddenly gelatinises to a white, semi-solid mass.If a portion of the latter be now treated with water, benzamide (in very small quantity) remains insoluble, although previously the sodium dibenzamide was completely soluble in that liquid. At the same time, there is I distinct odour of ethyl benzoate noticeable. As yet, however, the &!tion is very incomplete, and atACTL-SIJBSTITUTED SODAMIDES ON ORGANIC ESTERS. 1 Ei25 higher temperatures it proceeds sufficiently far to give a large quantity of benzamide. A t the same time, much undecomposed sodium dibenz- amide remains, and if there has been an excess of sodium ethoxide the ester formed is mostly saponified, giving sodium benzoate. The change may be represented thus : (C,H,*CO),NNa + EtOH + EtONa -+ /OEt C,H5-CO*NHNa + C,H,*C’OEt .\ONa /OEt \ONa C,H,*C-OEt -+ C,H,*CO*ONa + Et,O. These changes a t once account for the peculiar observations made in the potassium alkylsulphate experiments. The benzethylamidq, ob- tained in the experiments with sodium dibenzamide, is a product of a secondary reaction between the alkylsulphate and the sodium benx- amide which is formed. The peculiar reversible nature of the reaction between alcohol and sodium dibenzamide led to a study of the conditions under which the opposite reaction takes place, and in general of the nature of the interaction between organic esters and sodium derivatives of primary arnides. R*CO*OR + R”*CO*NHNa --+ $:zE>NNa + R-OH It was found that the reaction is general, except with derivatives containing the radicle -CH,*CO- in the groups R’sCO- and R”C0- (for example, aliphatic or phenyl aliphatic esters).Thus, in the aromatic series, by heating an acyl-substituted sodamide with an ester, a general change may be brought about between the groups -CO*NHNa and -GOOR, in which R-OH is eliminated and a magma obt,ained consisting largely of the sodium derivative -CO*NNa*CO-, from which the secondary amide may be prepared. Dibenzamide, for instance, may easily be obtained in this way from ethyl benzoate and sodium benzamide, and in a limited sense the reaction may be employed as a general method of synthesis of secondary amides. Two new mixed derivatives, R*CO*NH*COR’, were thus obtained in putting the method to a trial. The mechanism of the reaction is apparently very simple and (as- suming the sodium compounds t o have the tautomeric structure) may be represented thus : /ONa /OH R*c<iF -R.OH R*C\ HC1 R*C\ R - c H.,s + lt.(JJ R‘C\O -+ ’ N + R*C<gK R*CCO1526 TITHERLEY: THE ACTION OF SODAMIDE AND OF To illustrate the difference exercised by the CH,*CO group, reference may be made t o the action of sodium acetamide on ethyl benzoate, in which benzamide and dibenzamide are obtained in molecular proportion. 2CH3*CO-NHWa + SC,H,-COOEt = (C,H,*CO),L?Na + but i t is difficult t o explain why it should take this course. step is possibly to be represented thus : This reaction may be expressed : C,H,*CO*NH, + 2CH,*C02Et + NaOEt, The first CH,-CO.NHNa + C,H,*CO*OEt -c C,H,*CO*NHNa + CH,*CO,Et, the formation of sodium dibenzamide being due to a secondary action between the ethyl benzoate and sodium benzamide.EXPERIMENTAL. Xodamide and Acetone." Pure acetone, prepared from the bisulphite compound and dried with anhydrous calcium chloride, was used. I n one experiment, 10 grams of finely powdered sodamide were covered with benzene, and treated with 20 grams of acetone mixed with 50 grams of benzene, this mixture being added in small portions. S n immediate reaction set in, w i t h steady evolution of ammonia and formation of a gelatinous, yellowish solid. This, which rapidly turned red when exposed to air, was found t o consist mostly of the sodium derivatives of the enolic forms of several condensation products. At the close of the reaction, which was completed by warming, the mass was treated with water and a reddish oil liberated, which was extracted by the benzene present and by fractionation resolved into a t least three different ketonic condensation products.The cil boiled between 100' and 230°, and by repeated fractionation a colourless oil was obtained boiling at 130°, which mas mesityl oxide; another was separated boiling a t 190-200', which, although i t did not solidify, showed the properties of phoi*one ; but the chief portion boiled a t 217-220° and came over as a pale yellow oil, volatile with steam, and having a strong, camphor- like odour. This substance, on analysis, was found to have the composition C9HI40, and therefore is isomeric with phorone : 0.1357 gave 0.3890 CO, and 0.1247 H,O. C = 78.18 ; H = 10.16. C9H,,0 requires C = 78.18 ; H = 10.1 4 per cent.Pui-ther investigation of the oil showed its properties to be identical * Since this paper was written, Freund and Speyer (Bey., 1902, 35, 2321) have published an account of the action of sodamide on acetolie and on ethyl acetate. Their observations agree with mine.-A. W.T.ACYL-SUBSTITUTED SOP AMIDES ON ORGANIC ESTERS. 1527 with those of isophorme. It was not further examined, since it has already been investigated by Knavenagel (Chem. Centr., 1897, ii, 698), Kerp and Miiller (Anncden, 1896, 290, 123), Bredt, and Rubel, and others, and its constitution placed beyond doubt. Sodanaide and Ethyl Acetate. Thirty-two grams of ethyl acetate freed from alcohol and acid and mixed with 200 grams of benzene were added gradually to 14 grams of sodamide in a flask fitted with a reflux condenser.The mixture, which soon grew hot, was cooled and well shaken, and when the action had moderated, gently heated on the water-bath for about 5 hours, during which ammonia was steadily evolved. On subsequent treatment with acetic acid, an oil was obtained from the benzene extract which boiled at 100--105" under 84 mm., and at 1 8 1 O under 760 mm. pressure, and was identical in every respect with ethyl acetoacetate. The yield of the latter is not so great as that obtained in the preparation from sodium and ethyl acetate, and this is due to several secondary changes occurring, notably those in which sodium acetamide and sodium acetate are formed. The gas evolved contained no ethyl- amine or ethylene, and was found t o consist entirely of ammonia.Sodamide and Ethyl Benzoate. As already mentioned, the results obtained in carrying out this reaction varied with the proportion of ester and sodamide used. I n one set of experiments, 2 mols. of sodamide and 1 mol. of ethyl benzoate mere taken, the ester being dissolved in twice its weight of benzene. The action was allowed to proceed quickIy by warming gently for about 6 hours. At the end of that time practically all the sodamide had disappeared (provided it had been very finely ground) and no more ammonia was evolved. The thick, semi-solid mass was drained on the pump, washed with benzene to remove small quantities of undecomposed ester, and dried in a vacuum. It contained a large quantity of sodium benzamide and sodium ethoxide, and when treated carefully with ice-cold water, a thick, brownish solid was precipitated, consisting of impure benzamide, which after one or two recrystallisa- tions was obtained pure and melted a t 128'.The yield varied between 30 and 40 per cent. of that required by theory, the ultimate reaction being expressed by the equation : C,H,*CO*OC,H, + 2NaNH2 = C,H,*CO*NHNa + C,H,*ONa + NH,. Sodium benzoate was always obtained as a bye-product in these reactions, the relative amount being increased by using large quantities1528 TITHERLEY: THE ACTION OF SODAMIDE AND OF of sodamide. No sodium dibenzamide was formed in those experiments where benzene was present as a menstruum (compare the action of phenyl benzoate on sodamide in presence of benzene, infra) ; but when benzene was absent and higher temperatures were employed, it was found that sodium dibenzamide was formed by a secondary change taking place between the ester and sodium benzamide (p.1530). Sodarnids and Phcnyl Benzoate. In the absence of benzene, the action between sodamide and phenyl benzoate is much more energetic than that between sodamide and the ethyl ester under similar circumstances; much more dilute benzene solutions of the phenyl ester were therefore employed in studying its behaviour with sodamide. Under these conditions, in the cold, a white, flocculent powder is formed slowly, at fist without evolution of ammonia, but on allowing the mixture t o stand the latter commences t o be formed, and on warming is rapidly liberated. I n one experiment, 5 grams of pure phenyl benzoate (m.p. 69O), dissolved in 20 grams of benzene, and 2 grams of finely powdered sodamide were taken. After heating the whole for two hours, the action was complete, and the contents of the flask formed a thick, white magma. This was found to be a mixture of sodium dibenxamide and phenoxide, and to contain no sodium benzamide. No trace of aniline was formed. The benzene, which was removed by draining hot on the pump, left no appreciable residue on evaporation, and the white solid remaining after removal of the benzene was completeely soluble in water, and in alcohol, giving a strongly alkaline solution of a slightly yellow colour. The aqueous solution, on exposure to atmospheric carbon dioxide, slowly deposited dibenzamide in clusters of long needles.The latter was obtained from the aqueous solution by treating it with a current of carbon dioxide after diluting it sufficiently to prevent precipitation of phenol from the sodium phenoxide present. A thick, semi-solid mass of fine, white needles was thrown out, which after recrystallisation from alcohol separated in thick prisms melting at 148'. The yield of dibenzamide was 64 per cent. of that required by theory. The filtrate from the dibenzamide contained only a little sodium benzoate and a large quantity of phenol, which was recovered in almost theoretical amount. An easier method of isolating dibenzamide from the aqueous alkaline solution is to acidify with acetic acid, after diluting, and 'digest the crystalline precipitate after washing, with aqueous sodium carbonate t o remove the benzoic acid present.ACYL-SUBSTITUTED SODAMIDES ON ORGANIC ESTERS.1529 Sodamide and Ethyl Oxalate. The necessary precautions were taken to ensure freedom of the ester from traces of acid and alcohol. When mixed with sodamide in the absence of a diluent, the action is very vigorous. If the sodamide is moistened with a little benzene and the two are mixed in a mortar and triturated together, there is an energetic evolution of 'ammonia, the whole grows very hot, and a yellowish-grey, friable solid is formed. If, on the other hand, the ester is well diluted with benzene, there is no reaction until the flask is gently warmed, and then a thick, white, flocculent powder begins to separate, without any appreciable evolu- tion of ammonia, until towards the end of the reaction if the tempera- ture is well regulated.The change which occurs is very similar t o that observed in the case of ethyl benzoate so far as one carbethoxyl group is concerned, inasmuch as i t ultimately becomes the amide group- ing. The second group becomes CO*ONa, thus resembling the formation of sodium benzoate. The final product obtainable, after treatment with water, is sodium oxamate, but a small quantity of oxnmide is also formed a s might be expected. In one experiment, equivalent quantities of sodamide (2 mols.) and ester (1 mol.) were taken, the latter being dissolved in ten times its weight of benzene, and after heating on the water-bath until ammonia ceased to be evolved, the greyish-white, gelatinous solid was filtered off hot.The benzene filtrate, on cooling, deposited a jelly identical with the undissolved solid, which (as the author has frequently observed among many sodamide derivatives) is quite appreciably soluble in benzene. The gelatinous solid mas only sparingly soluble in alcohol, although readily so in water, except for a small quantity of undis- solved oxamide. A portion which had been dissolved in alcohol gave, with alcohoIic silver nitrate, a deep orange precipitate darkening on standing, characteristic of amides in which a hydrogen atom is replaced by sodium (compare Trans., 1901,79, 409). Treatment with water im- mediately converted the gelatinous solid into sodium oxamate, and on adding to the filtered strong aqueous solution one and zl half volumes of alcohol the pure sodium salt was precipitated as a thick, white, gelatinous mass.The yield of oxamate was very satisfactory. No oxamethane could be isolated. The action of sodamide on 6enzinaino-ethyZ ether was examined concurrently with that on esters, . In presence of benzene, no action occurs at first, but after a short time the mixture grows warm and the sodamide rapidly disappears, while ammonia is steadily evolved and sodium ethoxide separates as a white, gelatinous solid. If this is1530 TITBERLEY : THE ACTTON OF SODAMIDE AND OF filtered off on the pump and the benzene distilled off from the filtrate, benzonitrile remains as a pale yellow oil. Apparently an additive compound is not formed, the elements of ethyl alcohol being simply removed from the ether thus : Ph*C(NH)-OEt = Ph*CN + EtOH. sbdizcm Benzamide and Ethyl Benzoate.Several attempts were made to bring about condensation between free benzamide and ethyl benzoate : that is, to eliminate alcohol and form dibenzamide, but the results were negative. On the other hand, in presence of sodium or sodium ethoxide in snfficient quantity, condensation a t once takes place a t about 180'; or if sodium benz- amide (separately prepared from benzsmide and sodamide) is heated with the ester, condensation takes place similarly and sodium dibenzamide results. The conditions necessary are best indicated by the following de- scription of an experiment. Powdered sodamide (1 mol.) was suspended in benzene and treated with benzamide (1 mol.) and ethyl benzoate (about 1$ mols.), and the mixture heated until a thick, white mass of sodium benzamide was formed and most of the ammonia expelled.The benzene was then driven off and the mixture heated at 200-215O in a flask provided with an air condenser. The contents, which liquefied and boiled, were kept a t this temperature for 15 minutes, whereby a viscid liquid was obtained, which, on cooling, set t o a trans- lucent solid. This consisted of sodium dibenzamide with unchanged ester and sodium benzamide. It was treated with warm water, and when completely disintegrated was made ice cold, and filtered from the soft mixture of ester and benaamide. The filtrate, which was turbid and strongly alkaline and contained sodium dibenzamide, was now carefully treated with acetic acid until nearly neutral and a white turbidity began to form.The acid was then added cautiously drop by drop, with shaking between each addition, until all the dibenzamide was precipitated. I n this way, it came down as fine needles, in the form of a very bulky precipitate making a white, seml-solid froth. (If the neutralisation is not carefully performed, the dibenzamide comes down impure as an oily precipitate, solidifying and clogging into lumps.) I n order to remove benzoic acid, which was usually present, the whole was rendered just alkaline with sodium carbonate, allowed t o stand for half-an-hour, filtered, and washed on the pump. The product was white, melted a t 145--147O, and after once recrystallising from alcohol was pure, melting a t 1499 The yield (on the benzamide taken and using an excess of ester) was only a little short of the theoretical, but in experiments where less ethylACYL-SUBSTITUTED SODAMIDES ON ORGANIC ESTERS.1531 benzoate was taken, or other conditions were not carefully regulated, it was much smaller : 0,1235 gave 6.9 C.C. moist nitrogen a t 19' and 768.5 mm. N = 6.45. C,,HIIO,N requires N = 6.22 per cent. Sodium Acetumide and Ethyl Benzoate. The result of the change which takes place between these substances was quite unexpected, and there was no formation of sodium acetyl- benzamide. The action was tried under several conditions, both in presence and in absence of alcohol. In the former case, acetamide was trsated with sodium ethoxide in alcoholic solution and then with ethyl benzoate. A jelly formed which was heated first to remove alcohol, and then, as i d t h e sodium benzamide experiments, at ZOOo, at which temperature a reaction set in with production of ethyl acetate in large quantity.On cooling and treating the product with water, a con- siderable bulk remained insoluble, consisting of benzamide (m. p. 127") and unchanged ethyl benzoate. The portion soluble in water contained sodium dibenzamide, and gave with acid a large quantity of a white, oily precipitate, quickly becoming solid and crystalline. From this, a small quantity of benzoic acid was removed with sodium carbonate, and the dibenzamide was recrystallised from alcohol. The yield was good, and the proportion to benzamide approximately molecular. Precisely similar results were obtained when the pure crystalline sodium acetamide obtained from sodamide was used, alcohol being excluded.Xgdium 3enzamide and Ethyl Acetate. Here also there is no formation of sodium acetylbenzamide. The experiments were carried out in sealed tubes at fairly high tempera- tures. The sodium benzamide was first prepared in the tube from sodamide and benzamide intimately mixed while dry and then moistened with a little benzene and heated in a water-bath until ammonia ceased to be evolved. After cooling, pure ethyl acetate in excess (2 mols.) was added, and the tube, after sealing, heated a t 170" for 3 hours. At the end of this time, the contents, which were brownish, were treated with water. A light layer of oil floated on top, which contained ethyl acetate, benzamide, and ethyl benzoate.The aqueous portion was washed with ether to remove traces of these substances, freed from ether, and then acidified with hydrogen chloride. A dirty, oily precipitate was obtained which contained ethyl acetoacetate and apparently some dibenzamide, but no acetyl- benzamide. Sodium benxumide and phenyl acetate at 190" gave similar results,1532 THE ACTION OF SODAMIDE ON ORGANIC ESTERS. The action between fatty esters in general and acyl sodamides is com- plicated, owing to the latter exerting a condensing influence, like sodium ethoxide, and to secondary changes. Similar results mere obtained in the reaction between sodium hem- amide and ethyl phenylacetute, C,H,*CH,*CO,Et, which was carried out at 200-230". Dibenzamide, and not benzylbenzamide (which was looked for), was the chief product obtained, owing to secondary changes.The mixed secondary amides, hippurylbenzamide, and salicylbenz- amide, which have not previously been described, were readily obtained in the following way. The reaction was not further investigated. Sodium Benxccmide and Ethyl Eipprccte. Hippurylbenxamide, C,H,* CO*NH*CH,*CO-NH*CO* C,H,. The reaction proceeds normally, but must be carried out with great caution at the lowest possible temperatures. If the mixture of ester and sodium benzamide be taken in small quantity only, it may be heated at about 150' for a very short time and quickly cooled down again, but if larger quantities be used and it is necessary t o heat for several minutes, the mass slowly becomes yellow and finally dark red.On cooling, a hard, brittle, transparent product is obtained, from which only a very small quantity, or none, of the mixed amide can be isolated, owing to its sodium derivative, which is unstable, having suffered decomposition. I n several experiments, the results mere negative even at so low a temperature as 125". The best results were obtained as follows. Benzamide and sodamide were converted into sodium benzamide, to one molecular equivalent of which 1+ mols. of ethyl hippurate were added, the two being well mixed in an open glass beaker and just moistened with a little benzene. The mixture was heated very cautiously a t a temperature not exceeding 100-110' (at which a re- action quickly sets in) for as short a time as possible, and only until the semi-liquid mass becqme homogeneous, this being assisted by stirring with a thermometer.No discoloration occurred. The pro- duct mas cooled, forming a soft magma, which was tben treated with ice-cold water and extracted once or twice with benzene t o remove un- changed amide and ester. The aqueous portion was filtered and cautiously acidified with hydrogen chloride, whereby an oily turbidity quickly solidifying to a mass of nearly white needles was thrown out. These were washed with sodium carbonate to remove any hippuric acid present, and recrystallised from alcohol. I n this way, hippuryl- benzamide was obtained as white clusters of long, silky needles melt- ing a t 179":3 : 5-DICRLORO-0-XYLENE. 1533 0,0984 gave 8.6 C.C. moist nitrogen a t 2 2 O and 762 mm. Hippurylbenzamide is sparingly soluble in cold, but readily so in hot, alcohol. It is insoluble in sodium carbonate solution, but readily soluble in sodium hydroxide. This aqueous solution of its sodium derivative, on acidifying, a t once gives a milkiness, immediately changing t o a voluminous precipitate of white needles. N = 9-92. C16H1403N2 requires N = 9.93 per cent. Sodium Benxamide and Methyl Xcd icybte. Scclicylbelzxamide, OH*C,H,*CO*NH*CO*C,H,. The sodium benzamide (1 mol.), prepared from sodamide as usual, was mixed with the ester (14 mols.) and heated at about 170' until the fused mass became homogeneous. After cooling, the product was treated with water, the unchanged amide and ester removed by filtra- tion, and the aqueous portion acidified with hydrochloric acid, when a thick, white, milky oil was precipitated which quickly solid3 ed t o crystalline lumps. These were removed, drained on a porous plate, and crystallised from alcohol. Fine prisms separated of pure salicyl- benzamide melting at 122' : 0.1012 gave 5.1 C.C. moist nitrogen at 233 and 759 mm. N=5*67. Cl,H,lO,N requires N = 5.80 per cent. Salicylbenzamide is soluble in hot water, from which, on cooling and long standing, i t separates as long, thick prisms. It is slowly soluble in aqueous sodium carbonate (compare dibenzamide), but much more readily so in sodium hydroxide, forming the disodium derivative, from which it is precipitated as needles on the addition of an acid. CHEMICAL LABORATORY, UNIVERSITY COLLEGE, LIVERPOOL.

ISSN:0368-1645    

DOI:10.1039/CT9028101520

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

3 : 5-DICRLORO-0-XYLENE. 1533 CLI.-3 : 5-DichZoro-o-xylene and 3 : 5-i%chloro-o- phthalic Acid. By ARTHUR WILLIAM CROSSLEY and HENRY RONDEL LE SUEUR. IN a recent communication to the Society (Trans., 1902, 81, S27), it was shown that when phosphorus pentachloride acts on dimethyldi- hydroresorcin, there is obtained about 80 per cent. of the theoretical quantity of 3 : 5-dichloro-1 ; l-dimethyl-A2 ‘‘-dihydrobenzene (I), to-15341 CROSSLEY AND LE SUEUR : 3 : 5-DICHLORO-0-XY LENE gether with a small quantity of a substance of higher boiling point, which has since been prdved to consist of 3 : 5-dichloro-o-xylene (11). It would appear that this substance is a normal product of the action of phosphorus pentachloride on dimethyldihydroresorcin, the amount obtainable being influenced, first, by the presence of excess of the pentachloride, and second, by the length of time during which the mixture is heated.When pure dichlorodimethyldihydrobenzene is heated with excess of phosphorus pentachloride in chloroform solution, it is almost completely transformed into dichloro-o-xylene. The posi- tion of the chlorine atoms in this substance is doubtless the same as in dichlorodimethyldihydrobenzene, namely, 3 : 5 , and this is confirmed by the numbers obtained for the magnetic rotation; it may aIso be mentioned that when 3 : 5-dichlorodihydrobenzene, is treated with phosphorus pentachloride it is converted into 3 : 5-di- chlorobenzene (details not yet published). The conversion of the hydroaromatic into the aromatic dichloride necessitates, however, the wandering of a methyl group, and the main point to be decided WAS the position taken up by this group.This is readily shown to be the ortho-position, for on oxidation with nitric acid the dichloroxylene is converted into a dichlorophthalic acid, which, as it gives the fluorescein reaction and also a characleristic anhydride, can only be 3 : 5-dichloro-o-phthalic acid. EXPERIMENTAL. The accumulated fractions of high boiling point (b. p. above 100' under 23 mm. pressure), obtained by the action of phosphorus penta- chloride on dimethyldihydroresorcin, were distilled in a vacuum, when after the third distillation nearly the whole passf?d over at 128 -129' under 23 mm. pressure. This substance gave the following numbers on analysis : 0.1330 gave 0.2645 CO, and 0-0566 K20.0.2266 required 0.4346 AgNO,. 3 : 5-Dichloroo-xylem is a faintly yellow, highly refractive liquid C = 54-30 ; H = 4.73. C1= 40.05. C,H,Cl, requires C = 54.85 ; H = 4.57 ; C1= 40.57 per cent.AND 3 : 5-DICHLORO-0-PHTHALIC ACID. 1535 with a slight aromatic odour. It boils a t 129' under 23 mm. or at 226' under the ordinary pressure, and on cooling solidifies to a mass of flaky needles which melt a t 3-4". Unlike dichlorodimet hyldi- hydrobenzene, which does not solidify on cooling in a freezing mix- ture, it does not decolorise a solution of bromine in chloroform, or decompose on standing. Claus and Kautz (Ber., 1885, 18, 1368) have described a dichloro-o- xylene boiling at 227' and melting at 3', but this substance cannot be identical with the above, as on oxidation (Claus and Groneweg, J.p ~ . Chem., 1891, [ii], 43, 252) it yields the entirely different 4 : 5-di- chloro-o-phthalic acid. Densities, Magnetic Rotation, and Rgractive Values of Dichloro-o. xyleize. The authors desire to express their thanks to Dr. W. H. Perkin, Densities : d 4'/4O= 1.2472 ; d 15'/15'= 1.2374; d 25'/25'= 1.2301. sen., for kindly determining the following physical data : Nagnetic Rotation. 15.1' 1.9614 15-41 1 t. Sp. rot. Mol. rot. The influence of chlorine displacing hydrogen in this compound may be seen as follows : Mol. rot. 3 : 5-dichloro-o-xglene ............... 15.411 ,, o-xylene (Trans., 1896,69, 1341) ... 13.345 C1, displaces H, ............ 2/ 2.066 C1 displaces H ......... ..,. 1.033 This amount is small, but is due to the position of the chlorine atoms (ibid., 1131), and the rotation is therefore confirmatory of the conclusion that the dichloro-o-xylene is a 3 : 5-derivative.Refractive Values. Density : 16*2'/4"= 1.23529. p-1. +. Line. t. Pa Ha ............ 16.2' 1.54492 0,44112 77.197 H, ............ 16.2 1.545194 0.45491 79.608 H, ............ 16.2 1.57295 0.46380 81*168 Dispersion : H,, - Ha= 3.971.1536 CROSSLEY AND LE SUEUR : 3 : 5-DICHLORO-0-XYLENE Action of Phosphorus Pentachloride on Dichlorodirnet~yldihydrobenxene. Seven grams of dichlorodimethyldihydrobenzene were heated with 20 grams of phosphorus pentachloride in chloroform solution for 6 hours, during which time a small amount of hydrogen chloride was evolved. *On working up the product in the usual way, 4 grams of a liquid mere obtained boiling between 224O and 228" and possessing all the properties of 3 : 5-dichloro-o-xylene.Oxidation of 3 : 5-Dichlovo-o-xylem to 3 ; 5-Dichloro-o~hthalic Acid. Sixteen grams of dichloroxylene were heated in quantities of 2 grams at a time with 15 C.C. of dilute nitric acid (35 C.C. of acid in 100 C.C. of water) in sealed tubes a t 190-200" until the whole of the oil had disappeared. I n some instances, on cooling, slender, white needles had separated, but in all cases the contents of the tubes were evaporated in a vacuum over caustic potash, when a solid residue of 18 grams was obtained, which, although purified by repeated crystallisa- tion from water saturated with hydrogen chloride, did not melt sharply. It contracted slightly about 1 30°, partially sublimed, and finally melted at 164" with evolution of gas.The whole was therefore heated with excess of acetyl chloride €or 3 hours, the latter evaporated, and the solid residue purified by crys- t allisation from light petroleum and analysed : 0.1718 gave 0,2768 GO, and 0.0198 H,O. C=43-94 ; H= 1.28. 0.1382 required 0.2153 AgNO,. C1= 32.53. C,H,O,Cl, requires C = 44.24 ; H = 0.92 ; C1= 32.72 per cent, 3 : 5-Dichlo~~o-o-p~thal~c anhydride is readily soluble in benzene, chloroform, or ether in the cold and crystallises from light petroleum (b. p. SO-10O0) in radiating clusters of glistening needles melting at 89". When heated with resorcinol and a drop of sulphuric acid, and the residue dissolved in caustic soda and poured into water, a brilliant green, fluorescent solution is obtained.3 : 5-Dichloro-o-phthalic Acid.-The anhydride is insoluble in cold water, but on boiling it slowly dissolves to form a strongly acid solu- tion, which, Qn evaporation in a vacuum, yields the acid as a white solid. It crystallises from water saturated with hydrogen chloride in masses of hair-like needles melting a t 164' with evolution of gas, and many degrees below the melting point there is slight contraction and sublimation. The acid is very read'ily soluble in the cold in water, alcohol, acetone, or ether, but not readily so in benzene or chloro- form even on boiling. It gives the fluorescein reaction, and, on heat- ing, sublimes in needles melting at 89" and consisting of the anhydride.AND 3 1 5-DICHLORO-0-PHTHALIC ACID.1537 Characteristic is the insolubility of the acid ammonium salt, which is precipitated on adding a solution of the acid to a solution of the neutral ammonium salt. On heating, the precipitate dissolves, and, on cooling, separates in long, slender needles. The silver salt, C,H,O,CI,Ag,, is obtained as a white, caseous pre- cipitate on adding silver nitrate in excess to a warm solution of the neutral ammonium salt. The silver was estimated by dissolving the salt in nitric acid and titrating with ammonium thiocyanate : 0.2228 gave 0.1064 Ag. C,H,O,Cl,Ag, requires Ag = 48.10 per cent, The diethyl ester, C,H20,C1,(C2H,),, prepared by treating the silver salt with ethyl iodide in dry ethereal solution, is an odourless, oily, faintly yellow liquid boiling at 312-313' under 760 mm.pressure : Ag= 47-78. 0.1420 gave 0.2582 CO, and 0,0530 H,O. C = 49.59 ; H = 4-14, C,,H,,O,CI, requires C = 49.48 ; H = 4.12 per cent. The and, C,,H,O,NCl,, obtained by heating the anhydride and the calculated amount of aniline a t 180" until no more gas was evolved, crystallises from alcohol in bunches of silken needles melting a t 150-150.5". The crystals are insoluble in water, but readily soluble in acetone, chloroform, or benzene, and possess a marked yellow colour which could not be removed by repeated crystallisation (com- pare Gtraebe and Gourevitz, Ber., 1900, 33, 2024) : 0.2918 gave 12 C.C. moist nitrogen a t 18" and 775 mm. C,,H70,NCI, requires N = 4.79 per cent. The imide, C,EI,O,NCl,, was prepared by passing dry ammonia gas into the molten anhydride. It is insoluble in water, and only sparingly soluble in benzene, chloroform, or alcohol on warming, and crystallises from the last-named solvent in small, glistening, yellow needles melting a t 208: 0*2746 gave 16.0 C.C. moist nitrogen at 21 -5' and 760 mm. N = 6.62 The colour of the crystals could not be removed by recrystallisation. N = 4.83. C,H,O,NCI, requires N = 6.48 per cent. CHEMICALABORATORY, ST. THOMAS'S HOSPITAL, S. E. VOL. LXXXI. 5 L

ISSN:0368-1645    

DOI:10.1039/CT9028101533

出版商:RSC    

年代:1902

数据来源: RSC

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15% RUSSELL ANb SMITH : NON-EXISTENCE OF THE GASEOUS CLIL-Nnn-existence of the Gaseous Sulphide of Carbon described by Denirqer. By EDWARD JOHN RUSSELL and NORMAN SMITH. IN 1895, Deninger (J. p . Chenz., [ii], 51, 346) described a gas which he considered to be a new sulphide of carbon having the formula CS. He prepared it (1) by heating together in a sealed tube chloroform and sodium sulphide ; (2) by subjecting to the same treatment a mixture of iodoform and silver sulphide ; (3) by the action of sodium on a mix- ture of car'bon disulphide and aniline. The gas was collected over caustic soda, and, although no analytical figures are given, the formula appears to be based on the fact that the sulphur dioxide formed on ex- plosion with oxygen has about the same volume as that of the carbon dioxide produced, No properties of the gas are mentioned save that it burns rapidly and is absorbed by alcohol and aniline.Although no further paper has been published dealing with the gas, descriptions of i t are given in two or three of the newer text-books, which do not, however, add anything to what Deninger has already stated. During the last two pears, we have made many attempts to prepare this compound, but without success, and we are forced to the conclusion that no gas of the formula CS is obtained by any of the methods described by Deninger ; the gases produced are invariably mixtures of known substances. It is known that during the combustion of any gaseous compound of lsulphur some of this element almost always burns t o sulphur trioxide, and only rarely is the whole of it converted into sulphur dioxide.When, for example, carbon disulphide is exploded with oxygen, the volume of the sulphur dioxide is never double that of the carbon dioxide, as required by the equation CS, + 30, = CO, + 2SO,, but is invariably less, the exact amount depending on the conditions of the explosion (Russell, Trans., 1900, 77, 352 ; see also Dixon and Russell, Trans., 1899, 75, 600). Consequently it is impossible to identify any gas frdm the ratio of the carbon dioxide to sulphur dioxide produced during explosion. Equally impossible, of course, is it to assign a formula to a new gas by use of this ratio; yet this appears to be what Deninger has done, Of the three methods described, that depending on the action of sodium on carbon disulphide mas dxamined first, as it seemed to promise a continuous stream of the gas.The instructions given are t o mix 15 grams of sodium in small pieces with 125 C.C. of dry aniline in a 500 C.C. flask, to pour on 150 c,c, of carbon disdphide, and blow outSUEPHIDE OF CARBON DESCRIRED BY DENIKGER. 1530 the small quantities of gas evolved with carbon dioxide. The gas is then to be passed through caustic soda, india-rubber, and triethylphos- phine, and collected over caustic soda. The object of the india-rubber and triethylphosphine is evidently to remove any carbon disulphide that may be carried over ; we made some experiments to see how far they would do this. Hydrogen charged with varying quantities of carbon disulphide was passed through lengths of tubing packed with rubber, but much of the carbon disulphide always remained unabsorbed. This agrees with an observation made by Hofmann (Bey., 1869, 2, 73) that carbonyl sul- phide cannot be completely freed from carbon disulphide by contact with india-rubber.Triethylphosphine in ethereal solution was next tried with a some- what better result, absorption of carbon disulphide being very com- plete at first, but in a short time the absorbing power mas exhausted, and carbon disulphide was easily detected in the escaping gases. This reagent makes an excellent purifier for small quautities of gas, but it is not suitable for large volumes. Aqueous sodium hydroxide only slowly and partially absorbs carbon disulphide. These preliminary trials showed that there was nothing t o prevent Deninger's gas containing carbon disulphide; the fact that it was actually present is indicated by his description of what happened on evaporation of some that he had condensed.H e states that the liquid rapidly diminished in volume, and the boiling point rose to 474 the boiling point of carbon disulphide. Sodium and aniline react t o produce hydrogen, which is therefore another constituent of the gas. Lastly, a mixture of sodium, aniline, and carbon disulphide was found to evolve hydrogen sulphide, slowly a t first, more rapidly afterwards. This was a third substance to be expected in the mixture. Our method of investigation was to estimate the amounts of hydrogen, carbon disulphide, and hydrogen sulphide present, and to see what volume, if any, was left unaccounted for.The analysis was carried out in accordance with the directions given in a previous paper, the detaiIs of which need not be reproduced here (Trans., 1900, TI, 352). Suffice it to say that, after removal of the hydrogen sulphide by lead dioxide, the residual gas was exploded with oxygen, the contraction was read, and the volumes of sulphur dioxide and carbon dioxide produced, and the amount of oxygen used, were determined. From three of the four independent equations thus obtained, it is easy, as shown ii. the above paper, to calculate the amounts of hydrogen and carbon disulphide ; if these values also satisfy the fourth equation, it follows that the results of the explosion are quantitatively accounted 5 ~ 21540 RUSSELL AND SMITH: NON-EXISTENCE OF T H ~ cras~ods for by these two gases, and that it is impossible to admit the presence of any other combustible gas.As a further check, the volumes of the gases found were added together and compared with that originally taken ; any difference might arise from the new gas sought for. A large number of analyses all agreed in showing that Deninger’s gas consists entirely of hydrogen sulphide, carbon disulphide, and hydrogen. The quantities varied considerably, but no evidence of any other constituent could be obtained. I n our experiments, we omitted the india-rubber and triethyl- phosphine purifiers, as being only likely t o introduce complications. Sometimes the gas was collected over potash, and sometimes over mercury; sometimes, too, it was passed through purified lead dioxide t o remove hydrogen sulphide-the result was invariably the same.The two analyses are fairly typical. 1. 2. Hydrogen sulphide .................. 10.0 8.2 Carbon disulphide .................. 19.6 22.1 Oxygen ................................. 1.1 1.2 Hydrogen.. ............................. 64.4 63.7 Nitrogen .............................. 4.3 5.0 Total ........................... 99.4 100*2 Oxygert used in Explosion : Calculated ........................... 83.7 75.1 Found ................................. S2.5 74.4 Equally definite results were obtained when the gas was resolved into its constituents by cooling. The gas was passed through a column of lead dioxide to remove hydrogen sulphide, a bulb surrounded by solid carbon dioxide, another bulb surroiinded by liquid air, and the residual gas collected in a eudiometer over mercury.I t was occasion- ally necessary t o drive the gas forward by carbon dioxide, as the rate of evolution was very slow; this carbon dioxide condensed at the temperature of liquid air, and the gas left uncondensed i n the Iast bulb was driven into the eudiometer a t the end of the experiment by a current of dry air. The separate products were then analysed. (a) The uncondensed portion consisted of hydrogen and air. ( 6 ) The solid which collected in the bulb cooled with liquid air was carbon dioxide. I n neither case could any trace of a sulphur com- pound be detected. ( c ) The bulb cooled with solid carbon dioxide contained a small quantity of a highly refractive liquid, and was sealed off while still surrounded by the cooling agent.It was transferred to the laboratorySULPHIDE OF CARBON DESCRIBED BY DENIKGER. 1541 vessel of the gas analysis apparatus, and the liquid allowed to mix with excess of oxygen, in which it completely volatilised. Analysis showed that the liquid was pure carbon disulphide. Deninger states that the gas is rapidly absorbed by aniline, and that great care is necessary in the preparation, otherwise all the gas is retained by this substance. As i t was possible that we had lost all the gas in this way, we varied the experiment somewhat, and allowed sodium to react with a mixture of equal weights of carbon disulphide and benzene. There was no visible reaction, but carbon dioxide was passed slowly through the mixture and collected without any previous washing.It had, taken up some carbon disulphide and benzene, but there was no iudication of any other gas being present. . The caused 1. 2. Carbon dioxide.. ...................... 61.8 64.5 Carbon disulphide .................. 35.4 32.9 Benzene ............................. 2.4 2.8 Total .......................... 99% 100 -2 - Volume of gas taken ............... 100 100 possibility still remained that the absence of reaction was by a film of sulphide protecting the sodium. In the next experiments, the liquid alloy of sodium and potassium was substituted for pure sodiuw, and the vessel continually, but gently, shaken to expose a fresh surface t o the action of the carbon disulphide. As in previous experiments, however, the gas obtained was simply a mixture of carbon dioxide and carbon disulphide with a little benzene, and showed no indication whatever of the presence of any other compound.Finally, sodium and carbon disulphide were allowed to react in a sealed apparatus fitted with a mercury gauge. The apparatus is Ggured in the sketch (p. 1542) : A is a tube containing sodium, spread by melt- ing over a considerable surface, and B is a bulb partly filled with carbon disulphide ; C is a mercury gauge. After exhausting the air and sealing off, the apparatus mas allowed to stand for some months at the temperature of the laboratory. The sodium became coated with a red substance, but on bringing the apparatus to the original temperature and pressure, it was found that the mercury stood a t its original level, and there had been no evolution of gas whatsoever.The carbon disulphide was found not to hold any gaseous compound in solution. We think these experiments show fairly conclusively that no gaseous substance is evolved during the reaction of sodium and carbon di- sulphide, and that the gas obtained by Deninger’s method is simply a mixture of hydrogen, carbon disulphide, and hydrogen sulphide.1542 NON-EXISTENCE OF THE GASEOUS SULPHlDE OF CARBON. The other two methods-the reaction between sodium sulphide and chloroform, and that between silver sulphide and iodoform-were not studied in such detail, but here, again, no indication could be obtained of the formation of any new gas. A mixture of potassium sulphide and chloroform was heated in a sealed tube at 180' for some hours : on opening the tube we found hydrogen sulphide, hydrogen chloride, unchanged chloroform, free sulphur, and a reddish-yellow liquid less volatile than chloroform, and having the charaeteristic odour of the alkyl sulphides.Somewhat similar results were obtained when a mixture of silver sulphide and iodoform (5 grams of each), was heated at 180'; the reddish-yellow liquid was obtained in this case also, together with much hydrogen and some carbon disulphide. The gas obtained had an extremely unpleasant odour. On explosion with oxygen, about 6 per cent. of sulphur dioxide was formed, accompanied by more than five times that amount of carbon dioxide ; this result is completely explained by the presence of the vapours of carbon di- sulphide and the yellowish-red sulphide, and indicates that in the latter compound there are four or more carbon atoms to each atom of sulphur. We could find no indication of any gas having the formula CS ; we cannot say, of course, that no such gas is present, as the complex nature of the products of the last two methods puts a quan- titative analysis out of the question; but we maintain that all Deninger's results can be completely explained without assuming the existence of any new gas. THE OWENS COLLEGE, MANCHESTER. SOUTH-EASTERN AGRICULTURAL COLLEGE, WYE, KENT.

ISSN:0368-1645    

DOI:10.1039/CT9028101538

出版商:RSC    

年代:1902

数据来源: RSC

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LOCALISATION OF PHOSPHATES IN THE SUGAR CANE. 1543 CLIII.-Note on the Localisatiou of Phosphates in the Supr Cane. By CHAS. HENRY GRAHAM SPRANKLING. SEVERAL investigators have shown that phosphoric acid, in the form of phosphates of calcium, iron, aluminium, &c., exists in the ashes of plants, but very little work appears to have been done in relation to the position of these salts in the plant. Nessler (Landw. Versuc?wStat., 1873, 16, 185) showed that in the case of vines the nodes contained a larger quantity of phosphates than the internodes. He also pointed out that the nodes left a larger percentage of ash on ignition than the internodes. This, however, does not touch the question of the proportion of these compounds in the roots, stems, and leaves respectively, In discussing the need of the sugar cane for phosphatic manures, it was suggested to me by Nr.Watts that it would be of interest t o ascertain the amounts of these phosphates present in the root-portion, stem, and leaves of that plant. The question of the amount of phosphate necessary for the growth of the cane is one of great importance to the planter in the West Indies, in view of the present depressed condition of those islands, No doubt a certain quantity of phosphoric acid in one form or another is necessary for the growth of the plant, but the results of the experiments on the need of the sugar cane f o r artificial phosphates such as basic slag, calcium super- phosphates, &c., have shown that the application of large quantities of such substances to land on which sugar cane is to be grown is not only unnecessary, but in many cases actually detrimental to the yield of sugar per acre.For the purpose of ascertaining the position of the phosphate in the plant, the sugar cane offers several advantages, chief of which is its freedom from branches, and also the ease with which the leaves fall from the stem. I n fact, when a cane is cut, it is rarely necessary t o strip the leaves from the stem, as they fall while the plant is growing, leaving only a few at the top. For the purposes of experiment, three canes of the variety known as the “White Transparent,” of good, vigorous growth and as free from disease as possible were selected. ( I t is practically impossible to obtain a cane entirely free from aEE disease, as every cane suffers more or less from the attacks of the fungus Tricosphteria sncchari.) These canes were cut off a t a distance of about one inch below the surface of the soil, the length of cane thus cut being about ten or eleven feet.On their arrival at the laboratory, they were carefully stripped of1.544 SPRANKLING: NOTE ON THE LOCALISATION OF whatever leaves were present, except those at the top. The top leaves were then very carefully taken off down to the growing point of the stem. The remaining portions of the canes mere then cut into four equal parts, each section being about two and a half feet long. (A few root hairs were present on the bottom sections, but these were neglected.) Each section and each set of leaves were then chopped into small pieces, carefully sampled by the method of quartering, and about 500 grams of each sample dried in the steam-oven for three days.A rapid preliminary drying is necessary in order to prevent fermenta- tion, For the further drying, each sample (of which there were fifteen) was then passed through a mill, again mixed by quartering, and about 15 grams of each put into a large weighing bottle and dried at a temperature not exceeding 110' until of constant weight. The substances to be estimated were the phosphoric acid, calculated as phosphoric oxide, and the silica. For this purpose, a modification of Fluckiger's method was used (Zeit. anal. Chern., 1889,27, 637). Ten grams of each sample were weighed accurately into a platinum dish and very gently ignited ; to prevent any possible loss, a large sheet of white paper was placed under the tripod on which the dish rested, and any particles which fell were swept back into the dish.A t this preliminary burning, it was not considered necessary to obtain the ash quite white, but great care was taken not to fuse it, as Raumer (Zeit. anal. Chem., 1882, 20, 375) has shown that if too high a temperature be used for the ignition, a part of the orthophosphates present may be con- verted into pyrophosphates, and thus cause a deficiency of phosphoric oxide in the estimation. The residual ash in each case was boiled for 10 minutes with 20 per cent. nitric acid, water added, and the whole filtered and well washed. The residue on the filter, together with the filter-paper (which had been previously tested f o r freedom from phosphates), was again ignited until a perfectly white ash was obtained.This process of extraction with nitric acid was repeated four times, the final residue being ignited and weighed and taken as silica after correcting f o r filter ash. The combined nitric acid extraction liquors and the washings were united in each case and evaporated to about 20 C.C. In one or two cases the nitric acid extract was evaporated to dryness and hydro- chloric acid added, but no silica separated.* Moreover, as the results were to be more comparative than absolute, the application of the same method throughout was sufficient. * Preis (Listy Chem., 13, 153) has shown that phosphoric oxide can be estiniated in the presence of silica without error, provided the precipitate be washed with pure cold wntor.PHOSPHATES IN THE SUGAR CANE.1545 1st section. The small volume of nitric acid solution was then nearly neutralised with ammonia and treated with 50 C.C. of ammonium molybdate in nitric acid and allowed to stand in a warm place for two days. AS in all cases, the phosphomolybdate precipitate mas of small amount, it was weighed directly in the usual way, and the phosphoric oxide 5aken t o be 3.5 per cent, of this weight. The results obtained are shown in the following tables, giving the actual percentages of phosphoric oxide and of silica obtained for each section and the leaves calculated on dry material. Pndsection ~ _ _ _ _ _ P,O,. ......................... SiO,.. ........................ Ratio --. ...........lOOP,O, s10, 0.147 0'638 23 *7 P,O, .......................... SiO,. ........................ Ratio ~ ........... 1 00 P,O, SiO, 0.045 0.530 8 -57 P,O,. ......................... SiO,. ......................... Ratio - ........... lOOP,O, SiO, 0'163 0'616 26 ' 5 3 Leaves. 0.194 2.744 7 -09 0.251 3.216 7'83 0'259 2.892 8 -95 0,053 0-606 8 '74 0'201 0'600 33'50 0.043 0.479 9 -04 Cane 11. Cane 111. Ird section. 0'019 0.564 3'32 0.050 0.499 10'06 0.038 0'582 6.63 th section. 0.105 0'486 21 '62 0.093 0.522 17-84 0.089 0.519 17.16 A.n examination of these figures will show the following points. (By the term '' phosphoric acid " in these conclusions is t o be under- stood phosphates of calcium, iron, aluminium, &.) ( a ) There is a n immediate absorption of phosphoric acid by the roots of the sugar cane, as shown by the higher figures for the fourth section (that nearest the roots).( b ) A very rapid transference of phosphoric acid to the upper parts of the plant, as given by the small figures for the middle sections. (c) A storage of phosphoric acid in tho leaves and upper parts of the stem. (The leaves, as they fall from the cane, are left as manure for the ensuing crop, and doubtless form a good source of phosphatic manure for the plant.) (d) As was only to be expected, the silica is highest in the leaves,1546 MALLET : ISOMETItIC: ANHYDROUS and the transference of this from the soil is carried out in a fairly regular manner. No attempt was made to ascertain the actual form in which the phosphoric acid existed in the plant, although a short qualitative examination of the ash of various parts of the pIant showed that calcium, iron, and aluminium were present in considerable quantities, and taking into account the work of Watson Smith on the ash of various Eucalyptus trees (Trans., 1880, 37, 416) it is probable that phosphates of these elements were the chief sources of the phosphoric3 acid present.

ISSN:0368-1645    

DOI:10.1039/CT9028101543

出版商:RSC    

年代:1902

数据来源: RSC

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1546 MALLET : ISOMETItIC: ANHYDROUS CLIV.-lsometric Anhydro,us Sulphates of the Form M”SO,,R’,SO,. By FREDERIC R. MALLET. IN a paper which appeared in March, 1900 (Trans., 77, 216), I de- scribed a series of isometric anhydrous sulphates having the common formula 2MSO,,R’,SO,, that were produced by fusing the constituent sulphates together in the proper molecular proportions. Since this paper was published, further experiments have led to the production, by similar means, of the isometric sulphates described below, which are allied t o those just alluded t o in their mode of crystallisation, but differ in their composition, one molecule only of the bivalent metal sulphate being present in them instead of two. Several sulphates of the constitution represented by M”SO,,R’,SO, have been previously described, the best known being perhaps the calcium sodium salt, which occurs naturally as the monoclinic mineral glauberite,” and has also been made artificially, both by fusion and in the wet way.So far as I have been able to ascertain, however, with the exceptions mentioned below in connection with the sulphates MgSO,,K,SO, and NiSO,,K,SO,, no account of the sulphates belong- ing to the isometric series, noticed in the present puper, has hitherto appeared, although the monoclinic hydrated congeners of most of them, M”SO4,R‘,SO,,6H,O, have been the subject of elaborate investi- gation, of late years especially by Tutton (Trans., 1893, 63, 337; 1896, 69, 344). I t is unnecessary to allude to the details of the method adopted for producing and examining the salts with which the present communica- tion is concerned, because such details are similar t o those already described in connection with the sulphates 2M’SO4,R’,S0,.* As laiigbeinite is the only mineral known as yet haviiig the formuIa 211z”S@,, R’,SO,, so glsuberite is the only one corresponding to M”SO!, R’,S04.SULPHATES OF THE FORM M”YO,,R’,SO,. 1547 The products obtained, whilst substantially isotropic, generally in- cluded more or less birefringent material. In some cases, only a few isolated specks of the latter were noticeable, which might be attributed to the original mixture of sulphates not having been in perfect molecular proportion, or to the proportion being slightly altered, during fusion, by elimination of sulphur trioxide, whereby a minute excess of R’,SO, was induced.I n other instances, the proportion was greater : though always quite subordinate, it was found to vary considerably in the same double salt as produced by different fusions, presumably owing to slight variations in the conditions of cooling. More commonly, the birefringent part was so intimately intercrystallised with the main mass as to be inseparable, but from certain specimens of three salts, MgSO,,Rb,SO,, MnSO,,Rb,SO,, and NiSO,,K,SO,, i t was possible to isolate, in a fairly pure condition, a sufficiency of the accompanying birefringent material for the estimation of one or other constituent, from which the composition of the substance could be calculated. The results gave the respective ratios, M”S0, : R‘,SO,= 2 : 3.07 ; 2 : 2.91 ; 2 : 3.21, or 2 : 3 nearly.On fusing the mixtures ZMgSO, + 3Rb,SO, ; 2MnS0, + 3Rb,SO,, and 2NiS04+3K,S0,, as a check on the above figures, the products obtained were all birefringent. The occurrence of similar products, mixed with the salts M’SO,,R’,SO,, is perhaps due in some instances to a small proportion of the solidifying material crystallising in accordance with the equation 4(M’S04 + R’,SO,) = 2~~”S0,,3R’,S04 + 2MS0,,R’2S0,. Where the las t-mentioned salt is isometric, in common with the corresponding sulphate M”SO,,R’,SO,, it would easily escape recognition when intercrystallised in trivial proportion through the great mass of the latter. But there are, of course, other conceivable modes in which the sulphate 2M‘SO4,3R,SO, might be balanced.That the occurrence of such birefringent substance, in the cases where it admitted of being separated from the main mass, at least, did not materially affect the composition of the latter, is shown by the following estimations : Main mass. SO,, found. SO,, required. MgSO,,Rb,SO,. .............. 41.51 41.35 per cent. MnSO,,Rb,SO,.. ............. 38.46 38.31 ,, NiSO,,K,SO, ............... 48.68 48.67 ,, The sulphur trioxide was not estimated in the remaining salts. In some there was practically no birefringent material, and in cases where it was inseparable from its host, the percentage of sulphur trioxide would necessarily equal the theoretical amount, experimental error and loss through decomposition of MSO, during fusion excepted. That the latter was insignificant could easily be seen by dissolving the double salt in water, when, generally, there was a mere trace of1548 MALLET : ISOMETRIC ANHYDROUS oxide as residue.Thus the residue left by the nickel potassium salt, which was greater than that of most of the others, only amounted to about 0.1 per cent. The crystals employed for measurement were, in some cases, very minute, and it mas not always practicable t o isolate and mount a single individual, so t h a t two or three crystals in parallel position were sometimes unavoidably used, Owing to this, and also to the faces, in some instances, having lost more or less of their original brightness, through incipient hydration on the Surface, the images available were not always satisfactory. To this cause may be ascribed, in part at least, the differences between the measured and calculated angles.A comparison of the details given respecting the isometric salts M”SO,,R,’SO, and 2WS04,R,’i30, shows that, with the doubtful ex- ception of MnSO,,Tl,SO,, the sulphates of the first-mentioned series crystallise in tetrahedral forms only. While the same is true in respect t o some salts of the composition 2MS0,,RiS04, in the crystals of others rhombic dodecahedra1 planes are present, and those of 2CoS0,,K,S04 are further modified by faces of the Cuba. Mugnesiurn Potassiune SulpT~ccte, Mg SO,, K2S04. The salt crystallises in tetrahedrons, which are more commonly unmodified, but are sometimes in combination with the tetrahedron of opposite sign, the planes of the latter, however, being usually sii5ordinate in their development : Measured.Calculated. 111 A iii ............ 109032’ 109’28’ The crystals generally (but not always) form groups, within each of which the orientation is parallel. As the most frequent result of this tendency, the individuals are arranged in columns of interpenetrant tetrahedrons with their centres in line, the columns themselves also being sometimes parallel t o each other. Compound tetrahedrons like- wise occur that are of large six0 compared with the individuals of which they are built up. The weight of a powdered sample so treated, while still slowly rising, after five months had increased by 3.41 per cent. only. For conversion into the salt MgSC),,K,SO,,GH,O, the percentage would be 36.69. Anhydrous magnesium potassium sulphate has been produced by Berthelot and Ilosvny through fusion of the constituent sulphates together (Ann. Chim.P?hys., 1883, [v], 29, 329), but as the crystallo- graphic character of the substance is not alluded to in their memoir, being foreign to the scope of their work, the salt is included amollgst, those here described. The salt absorbs water very slowly when exposed to the air.SULPHATES OF THE FORM M”SO,,R’,SO,, 1549 Magnesium Rubidium Sulphate, MgSO,, Rb,SO,. The tetrahedrons formed by the crystals are sometimes unmodified, but are most frequently in combination with the tetrahedron of oppo- site sign, the latter being generally subordinate : Measured. Calculated. 111 A 111 ............ 70’34’ 70’32’ 111 A 111 ............109031’ 109’28’ The faces are sometimes cavernous, in some cases so much so that the crystals become skeletons, Similar cavernous faces were also noticed on the faces of some of the other salts, although scarcely to such ar? extreme degree. More than three trihedral angles of any individual tetrahedron are rarely exposed to view, but of these, in some crystals, only two are truncated by planes of the opposite tetra- hedron; the crystal then, when the faces of the two tetrahedrons are equally developed, being equivalent to an octahedron with two opposite sides wanting, which is, geometrically, a rhombohedron. There is a very strong tendency to crystallisation in parallel position, in modes similar to those affected by the preceding sulphate. The salt becomes slowly hydrated on exposure to the air in powder.After seven months (with a still increasing weight), 8.02 per cent. of water had been absorbed by the portion experimented on, the theoreti- cal amount for conversion into the hexahydrated sulphate being 27-91. Munganous Pot am ium Sulphate, MnSO,, K,SO,. The salt is reddish-white, and forms crystals quite similar to those of magnesium potassium sulphate, both in the relative frequency of occurrence, and degree of development, of the + and - tetrahdral planes, and also in the modes according to which the crystals group themselves in parallel position : Measured. Calculated. 111 A i i i ............ iogom’ 109’28’ This salt resembles the sulphnte 2MnS04,K2S0, in its stability when exposed to the air. After 44 months’ exposure of a pulverised sample, the absorption of water, which varied with the weather and was evidently hygroscopic, never exceeded 0.17 per cent.Mangunourr Rubidium Xulphate, MnS04,R b,SO,. The crystals are reddish-white, and similar to those of magnesium rubidium sulphate in the relative frequency of occurrence, and degree of development, of the i- and - tetrahedrons, and likewise in the1550 MALTJET : ISOMETRIC ANHYDROIJS occurrence of pseudo-rhombohedrons. due to the elongation of the crystals parallel to a tetrahedral edge : Another mode of distortion is Measured. Calculated. 111 A i T i ............ 109033' 109'28' There is a very strong tendency to grouping in parallel position after the modes previously alluded to : the product of one particular fusion showed faces of compound tetrahedrons with sides nearly a centimetre long.On treating it portion of the salt in the same may as in the preceding case and for the same period, the water absorbed at no time exceeded 0.51 per cent. Manganous Tl~mZZous Xulplmte, MnSO,,Tl,SO,. Manganous thallous sulphate is reddish white. The tetrahedral crystals are sometimes unmodified, but usually the + and - forms are both present, one being predominant. Their relative devaopment, however, varies much, and (geometrically) octahedral crystals are by no means rare : Measured. Calculated. 111 A iii ............ 109027' 109O28' 111 A in ............ 70027' 70'32' The free (top) surface of cooling, besides a multitude of facets obviousIy belonging to crystals like those just mentioned, generally showed a small proportion of square or short rectangular facets, suggestive of cubic crystallisation.No actual cubic crystals, however, were noticed, or any cubic faces replacing tetrahedral edges. There is a strong tendency to grouping in parallel position. On treating a portion of the salt like the corresponding potassium sulphate, and for the same length of time, the weight fluctuated, with a maximum increase of 0.52 per cent. only. Nickel Potassium Subhate, NiSO,,K,SO,. This sulphate is mentioned by Gmelin (Handhuch der Chemie, 3, 360), without allusion, however, to its mode of crystallisation, It is yellowish-brown when hot, yellow after cooling, and cry stallises in unmodified tetrahedrons : M.easured. Calculated. 111 A i i L ......... 109'29' 109'28' The crystals generally show a strong tendency to grouping in paraliel position, after the modes already described, but sometimes the orientation is quite irregnlar.SULPHATES OF THE FORM M”so,,R’,so,, 1551 The anhydrous salt is converted, comparatively quickly, into the hydrated sulphate, NiS0,,K2S0,,6H,0, on exposure to the air for a sufficient length of time.A pulverised sample so treated until the weight no longer increased absorbed 32.17 per cent. nf water, six mols. requiring 32.85. Cobaltous Potasoium XuZphccte, c‘oS0,,K,S04, Cobaltous potassium sulphate is violet when not, and violet-crimson after cooling, and occurs in unmodified tetrahedrons : Measured. Caleula ted. 111 A iii ............ 109032’ 109O28’ The nickel and cobalt salts are very similar in their tendency towards parallel orientation, Like the last-mmtioned sulphate, that of cobalt changes somewhat rapidly on exposure to the hexahydrated salt, While the theoretical percentage of water required is 32-82, an absorption of 32.05 was obtained experimentally, The sulphates of the following metals mere also fused together, in the same molecular proportion as the preceding : - I L - Z n + K L - Ni+Rb Co+Rb Zn+Rb Mg+Cs Mn+Cs Ni-FCs Uo+Cs Zn+Ca Mg + T1 - Ni+T1 Co+T1 Zn+T1 The resulting products were all of non-isometric crystallisation, as shown, in most cases, by their external characters, and in all by their birefringence. Whilst many of them, at least, afforded no obvious indication of the two sulphates being in other than homogeneous com- bination, it would be unsafe to regard such homogeneity as proven without a .more detailed examination of the products than I have given to them.

ISSN:0368-1645    

DOI:10.1039/CT9028101546

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1552 POPE AND NEVILLE ; ASYMMETRIC CLV.- Asymmetric Optically Active Selenium Corn- pounds and the Sexavtxlency of Selenium and Sulphw. d- and l-P~~erLylmethylselenetine Salts. By WILLIAM JACKSON POPE, F.R.S., and ALLEN NEVILLE, B.Sc. THE fact that amorphous substances can exhibit optical activity as a result of the presence in the molecule of asymmetric atoms other than those of carbon having been placed beyond question by the work of Pope, Peachey, and Harvey (Trans,, 1899, 75, 1127; 1900, 77, 1072; 1901, '79, 828), it is important that the results obtained by these authors should be extended to compounds of as large a number of elements as possible, as the foundation would thus be laid for a general stereochemical scheme which would embrace all the elements. For this reason, we have investigated substances containing an asymmetric quadrivalent selenium atom and, in the present paper, contribute results proving that such an atom has a tetrahedral environment and gives rise to optical activity.For the purposes of this investigation a mixed alkyl selenide was naturally required, and, methods for the preparation of such sub- stances not having been previously devised, it mas proposed to prepare methyl ethyl selenide by a series of steps sufficiently indicated by the following scheme : (C,H5),Se -+ C2H,*Se*Se*C,H, -+ C,H,*SwNa -+ C,H,*Se*CH,. Although we proceeded far enough with this course to ascertain definitely that it mould lead to success, i t was found that the manipulation of large quantities of the volatile diethyl diselenide, unless performed with irksome precautions, gave rise to unpleasant physiological symp- toms in the operator ; this plan of attack was therefore abandoned in favour of one based on the following considerations.The difficulties encountered in dealing with the dialkyl selenides are due to their volatility and might be avoided by the use of a selenide of high molecular weight, provided that such a substance had, in other respects, the necessary properties; that is to say, if phenyl methyl selenide, pre- pared by the following series of steps : (C6H,j2Se -+ C6H,'Se*Sf?*C6H5 -+ C,H,*Se-Na -+ C,H,*Se*CH,, would combine with bromoacetic acid to give a stable selenetine of the CH3>Se<&,,co2H, the desired object would be at- constitution tained. Although phenyl methyl sulphide is quite inert towards C6H5 bromoacetic acid, it was thought probable that, since the oxygenOPTICALLY ACTIVE SELENIUM COMPOUKDS.1553 in alkyl oxides exhibits more reluctance than the sulphur in alkyl sulphides t o become quadrivalent, the selenium in alkyl selenides might have so great a tendency t o become quadrivalent as to counter- act the inhibiting influence of a phenyl group and so cause phenyl methyl selenide to combine readily with bromoacetic acid. This sur- mise proved correct, and a striking illustration is thus furnished of the periodic gradation in the ease with which bivalent oxygen, sulphur, and selenium become quadrivalent. The only selenetine previously described is that prepared from diethyl selenide and bromoacetic acid by Carrara (Gaixetta, 1894, 24, ii, 173) ; this author, however, gives no data from which an opinion can be formed as t o the relative stability of the thetines and selenetines. It is important to note in this connection that whilst an aqueous solution of diet,hylthetine bromide evolves a strong odour of ethyl sulphide during evaporation on the water-bath, phenylmethylselen- etine bromide remains practically odourless under similar conditions ; although the latter substance contains the highly acidic phenyl group, the basic character of the quadrivalent selenium atom imparts great stability to the selenetine.Phenyl Methyl Selenide, C6H,*Se*CH,. Diphenylsulphone is converted into diphenyl selenide and the latter into diphenyl diselenide by the convenient method given by Krafft and Lyons (Ber., 1894, 27, 1761) ; the diselenide (1 mol.) is converted into sodiophenyl selenide by adding sodium wire to its absolute alcoholic solu- tion and, on running in methyl iodide (2 mols.), vigorous action ensues with formation of phenyl methyl selenide and separation of sodium iodide.After distilling off most of the alcohol, treating with water, and extracting with ether, the ethereal solution is dried over potash and distilled ; a good yield of phenyl methyl selenide is obtained as a pa10 yellow oil which boils at 200-201* without decomposition, and has a not unpleasant aromatic, garlic-like odour : 0.1623 gave 0.2922 CO, and 0.0684 H,O. C7H,Se requires C = 49.12 ; H = 4.67 per cent. Phenyl methyl selenide is the first mixed alkyl selenide which has been described, and seems to be much more stable in the air than the phenyl hydrogen selenide prepared by Krafft and Lyons (Zoc.cit.). C = 49.04 ; H = 4.68. On warming a mixture of phenyl methyl selenide and bromoacetic acid in molecular proportion on the water-bath, combination takes VOL. LXXXI. 5 M1554 POPE AND NEVILLE : ASYMMETRIC place rapidly with development of heat and formation of a white, crys- talline mass ; after crystallisation from a mixture of ether and alcohol, the selenetine bromide is obtained in white, crystalline scales melting at 11 1'. It is very soluble in water or alcohol, but practically insoluble in ether : 0-1554 gave 0°1985 CO, and 0,0504 H,O. C = 34-81 ; H = 3.60. 0.3400 ,, 0.08772 Br with standard AgNO,.Br=25*80. C,H1,O,BrSe requires C = 34.83 ; H = 3-54 ; Br = 25.81 per cent. Resolution of Externally Compensated Phrzylrnetliylseleneti~~ Bromide. On exactly precipitating externally compensated phenylmethyl- selenetine bromide with silver d-bromocamphorsulphonat e in hot aqueous solution, filtering off the silver bromide and evaporating the filtrate to dryness, a white, crystalline residue is obtained ; this is systematically fractionally crystallised from absolute alcohol, the less soluble fractions being passed in one direction through a series of beakers, whilst the more soluble portions proceed in the opposite direction. The least soluble constituent is d-phenylmethylselenetine d-bromocamphorsulphonate (d-B, d-A), and separates from alcohol in small, colourless, rectangular tablets melting at 168'.The crystals apparently belong to the orthorhombic system and exhibit the forms (OOl), (101), and (011); the form (001) is predominant, the c-axis is the acute bisectrix, and the optic axial plane is ac(100). The optic axial angle is large, and the double refraction is positive in sign : 0-1511 gave 0,2336 CO, and 0.0630 H,O. C19H,,06BrSSe requires C = 42.22 ; H = 4.62 per cent. The proof of the purity of the salt and the final determination of its optical constants are given by the following measurements of the rotatory powers of three consecutive fractions obtained on crystallising it from alcohol : (1) 0,2216 gram, made up to 25 C.C. with water, gave a, +1*09O in a 2 dcm. tube ; whe$ce [a], + 61.5' and 1x1, + 332.0'. (2) 0,2528 gram, made up to 25 C.C.with water, gave al, +1*24O in a 2 dcm. tube ; whence [a], + 61.3' and [MI, + 331.1'. (3) 0.2356 gram, made up to 25 C.C. with water, gave a, + 1.15' in a 2 dcm. tube; whence [a], + 61.0' and [MI, + 329.5'. The mean values [a], + 61.26' and [MI, + 330.8'are thus obtained, and since the molecular rotatory power of the d-bromocamphorsulph- onic ion in aqueous solution is [MI, +270*0', it follows that the corresponding value for the d-phenylmethylselenetine ion is C=42*15 ; H=4-63. [MI, +60*8'.OPTICALLY ACTIVE SELENI WM COMPOUNDS. 1555 After separating the d-phenylmethylselenetine d-bromocamphor- sulphonate as far as possible, there remains a very soluble residue which has a tendency to become gummy, but by repeated crystallisa- tion from water, E phenylmet hy 1 selenet ine d- bromocamphorsulphonnte is obtained in minute, white scales, It is finally purified by crystal- lisation from alcohol, and forms aggregates of colourless needles melt- ing at 151O : 0.1613 gave 0.2493 CO, and 0.0671 H20.C,,H,,O,BrSSe requires C = 42.22 ; H = 4-62? per cent. The purity of this material was proved, and its rotatory constants mere ascertained, by the foWowing determinations of the rotatory power of three consecutive fractions : (1) 0.2461 gram, made up to 25 C.C. with water, gave a, +0.76" in a 2 dcm. tube; whence [.ID + 38.6' and [MID + 208.4O. (2) 0.2371 gram, made up to 25 C.C. with water, gave uD +0*74O in a 2 dcm. tube ; whence [.ID + 39.0' and [MID + 210.7'. (3) 0.2511 gram, made up to 25 C.C.with water, gave aD +0*78" in a 2 dcm. tube ; whence [a], + 3Sa80 and [MI, + 209.7'. The mean values [a], + 38*S1° and [MI, + 209.6" are thus obtained, and, taking [MI, + 270 0" for the d-bromocamphorsulphonic ion, the molecular rotatory power of the I-phenylmethylselenetine ion is calcu- lated as [MI, - 60*4", a number which agrees very closely with the value [MI, + 60.8' obtained above for the enantiomorphously related ion, d- and 1- Pheny Zmet/'lylse Zene t ine PZa t inich Zoi*ides, C = 42.09 ; H= 4.58. On adding a cold alcoholic solution of platinic chloride t o an alcoholic solution of either of the above d-bromocamphorsulphonates containing a little hydrochloric acid, the corresponding platinichloride slowly separates as a microcrystalline, yellow powder ; the platini- chlorides are insoluble in water or alcohol, but very soluble in acetone, and crystallise from a hot mixture of acetone and water in minute, yellow prisms melting a t 171".The first of the appended analyses was made on d-phenylmethylselenetine platinichloride, and the second on its enantiomorphously related isomeride : (1) 0.1835 gave 0.1672 GO2 and 0.0414 H20. C=24.85 ; H=2050. (2) 0.1923 ,, 0.1752 CO, ,, 0,0432 H,O. C=24*SO ; H=2*49. C,,H,,O,CI,PtSe, requires C = 24.88 ; H = 2.53 per cent. Three successive fractions from the crystallisation of the d-platini- chloride gave the following determinations of rotatory power : 5 ~ 21556 POPE AND NEVILLE : ASYMMETRIC (1) 0,5124 gram, made up to 25 C.C. with acetone, gave aD +0.26' i n a 2 dcm. tube ; whence [a], + 6.3' and [MI, + 55.0'.(2) 0.5561 gram, made up to 25 C.C. with acetone, gave aD + 0 * 2 8 O in a 2 dcm. tube ; whence [a], + 6.3' and [MID + 54.6'. (3) 0.5474 gram, made up to 25 C.C. with acetone, gave a, +0-28' in a 2 dcm. tube ; whence [ a], + 6.4" and [MI, + 55%'. The mean values are thus [.ID + 6.34' and [MI, + 55.0'. A 8imilar set of three values were also obtained from consecutive fractions of the enantiomorphously related isomeride. in (1) 0.6124 gram, made up to 25 C.C. with acetone, gave aD - 0.31O a 2 dcm. tube ; whence [a], - 6.3' and [MI, - 54.8'. (2) 0.5225 gram, made up to 25 C.C. with acetone, gave uD - 0.26' in a 2 dcm. tube ; whence [a]= - 6-24' and [MI, - 54-03. (3) 0.4812 gram, made up to 25 C.C. with acetone, gave aD - 0.24' in a 2 dcm. tube ; whence [a], - 6.2' and [MI, - 54.1".The mean values, namely, [a], - 6.25' and [MI, -5403'~ are in close numerical agreement with those obtained for the enantiomor- phously related isomeride. The preparation in a pure state of these optically active platinichlorides containing no asymmetric carbon atoms completes the proof that the presence of an asymmetric quadrivalent selenium atom causes optical activity. P~enylmethylselenetine Mercuriodide, CH H3>Se<CH,.C0,H,HgT; I 6 5 On adding a concentrated aqueous potassium iodide solution of mercuric iodide (1 mol.) to one of either d- or I-phenylmethylselenetine d-bromocamphorsulphonate or of externally compensated phenylmethyl- selenetine bromide (1 mol.), the optically inactive mercuriodide separates quantitatively as a flocculent, white powder ; after crystal- lisation from dilute alcohol, it is obtained in colourless, crystalline scales melting at 141-142'.The substance is freely soluble in acetone, less so in alcohol and practically insoluble in water or ether. The polarimetric examination of this salt in acetone solution showed it to be optically inactive although prepared from a salt of the pure optically active selenetine, and on making a number of pro- parations of the mercuriodide from d- and I-phenylmethylselenetine d-bromocamphorsulphonate and from the externally compensated bromide, it was found that the same substance is produced from each of these three materials; the salts from the three sources are optically inactive, have the same microcrystalline properties, and no change of melting point results on mixing any two of them.This result is a very remarkable one, because Pope and HarveyOPTICALLY ACTIVE SELENlUM COMPOUNDS. 1557 showed (Zoc. cit.) that no optical inversion attends the formation of d- or I-benzylphenylallylmethylammonium mercuriodide from its constituent salts, and Pope and Peachey (Trans., 1900, '7'7, 1072) showed that no racemisation takes place during the formation of d-methylethylthetine platinichloride, whilst in the present paper it is shown that the d- and I-phenylmethylselenetine platinichlorides are still optically active ; optical inversion therefore is not an invariable accompaniment to the formation of a double salt or salt of a complex acid. I n order to preclude the possibility that the selenetine mercuriodides described above are really optically active, but have very small specific rotatory powers and as the observation of the racemisation of the mercuriodides should have important bearings on the constitution of such substances and on the valency of sulphur and selenium, it seemed desirable to prepare and examine the mercuriodides of an optically active sulphonium base. For this purpose, we selected the d- and I-methylethylphenacyl- thetine d-bromocamphorsulphonates prepared by Smiles (Trans., 1900, 77, 1 174) rather than the d-methylethylthetine d-bromocamphor- sulphonate previously described by Pope and Peachey (Zoc.tit.)? con- sidering the higher rotatory powers exhibited by the former substances as likely to facilitate the investigation.On repeating Smiles's work, much higher values were obtained for the rotation constants than were given by him, and it is hence to be concluded that he did not succeed in obtaining the active thetine salts in a state of purity. We find that I-methylethylphenacylthetine d-bromocamphorsul- phonate melts at 196', and four consecutive fractions of the carefully purified salt gave the following determinations of rotatory power : (1) 0.3545 gram, made up to 25 C.C. with water, gave uD +lolo' in a 2 dcm, tube ; whence [ a ] , + 41.1' and [MID + 207.6O. (2) 0.4288 gram, made up to 25 C.C. with water, gave uD + 1'26' in a 2 dcm. tube; whence [ a l l ) +41*8' and [MID + 210.9'. (3) 0.3836 gram, made up to 25 C.C. with water, gave uD + 1'18' in a 2 dcm.tubo; whence [a], +42*4' and [MI, +213*9'. (4) 0.4109 gram, made up to 25 C.C. with water, gave uD + 1'22' in a 2 dcm. tube; whence [ a ] , + 41.5' and [MIL, + 209.8'. The mean values for the salt are {a]D + 41.7' and [MID -k 210.6'. d-Methylethylphenacylthetine d-bromocamphorsulphonate melts at 180-181' and two consecutive fractions of the salt gave the following results : (1) 0.4714 gram, made up t o 25 C.C. with water, gave uD + 2'29' in a 3 dcm. tube; whence [ a ] , + 653O and [MI, + 332.5'. (2) 0.3525 gram, made up to 25 C.C. with water, gave uD + 1'52' in a 2 dcm. tube; whence [ a ] , +66.0° and [MI, + 333.2'.1558 POPE AND NEVILLE : ASYMMETRIC The mean values are thus [ a ] , + 65.9' and [MID + 332.8'. The molecular rotatory power of the optically active methylethyl- phenacylthetine ion in aqueous solution, calculated as one-half the difference of the values for the d-bromocamphorsulphonate of the d- and 1-bases, is thus : [MID = +_ (332*8/2- 210.6/2) = +, 61.1' ; the value calculated from smiles's results, namely, [MI, 2 19-4', is less than one-third of this.The d- and I-methylethylphenacylthetine picrates, prepared from the corresponding d-bromocamphorsulphonates, mere fractionally crystal- lised from acetone and the rotatory powers of two successive fractions of each determined with the following results : d- Me t lb y let h y Zphenac y I the t ine l'icra te . (1) 0.4512 gram, made up to 25 C.C. with acetone, gave uD + 0'21' in 0,5121 gram, made up to 25 C.C. with alcohol, gave uD +Oo20' in a (2) 0.3912 gram, made up to 25 C.C.with acetone, gave aD +Oo18' 0.4411 gram, made up to 25 C.C. with alcohol, gave C C ~ +Oo17' in 8 2 dcm. tube ; whence [a], + 9.7' and [MID + 41.3'. 2 dcm. tube ; whence [a]D + 8.1' and [MI, +34*6'. in a 2 dcm. tube ; whence [ aID + 9.6' and [MI, + 40.8'. a 2 dcm. tube ; whence [a], + 8.0' and [MID + 34.2'. l-Methylebhylphenacylthetilze Picrate. (1) 0*4912 gram, made up to 25 C.C. with acetone, gave a,, - 0'23 0.4512 gram made up to 25 C.C. with alcohol, gave aD - 0'18' in a (2) 0.4775 gram, made up to 25 C.C. with acetone, gave a, -0'23' 0.4621 gram, made up to 25 C.C. with alcohol, gave U, - 0'19' in a in a 2 dcm. tube; whence [a], - 9.7" and [MIu - 41.59 2 dcm. tube ; whence [ a ] , - 8.3' and [MI, - 35.4'. in a 2 dcm. tube ; whence [ a ] , - lo*oo and [MID - 42.7".2 dcm. tube ; whence [a],, - 8.5' and [MI, - 36.4'. d-Methylethylphenacglthetine picrate thus gave the mean values [a], + 9-63' and [MID + 41.1' in acetone solution, and [ a ] , + 8-06' and [MI, i- 34.4' in absolute alcoholic solution. The enantiomorph- ously related salt giVeS [a], - 9.88' and [ MI, - 42.1' in acetone and [a], - 8.42' and [MI,, - 35.9' in alcohol. 1- Me th y le t h y Zp henacy lt he tine l'ht inic h Zoride, This salt is obtained in golden-yellow scales melting at 184', on crystallising from dilute acetone the precipitate formed on addingOPTICALTdY ACTIVE SELENIUM COMPOUNDS. 1559 acidified platinic chloride solution to the corresponding d-bromocamphor- sulphonate ; it is very sparingly soluble in the ordinary solvents : Pt = 24.62.09412 gave 0,0584 Pt. C22H,o02CI,S,Pt requires Pt = 24.43 per cent. 0.2112 gram, made up to 50 C.C. with concentrated hydrochloric acid, gave aD -0.13" in a 4 dcm. tube; whence [a] -7.7" and [MI, - 6 1 ~ 4 ~ . It is thus evident that the formation of the platini- chloride is not accompanied by optical inversion. Methyletlqlphenacylthetine Memzcriodide, C,H, CH,*CO*C,H,,HgI,. On adding a concentrated solution of mercuric iodide (1 mol.) in aqueous potassium iodide to one of d- or I-methylethylphenacylthetine d-bromocamphorsulphonate or of externally compensated methylethyl- phenacylthetine bromide (1 mol.), the optically inactive mercuriodide is precipitated. I t is insoluble in benzene, ethyl acetate, or water, but crystallises from acetone or dilute alcohol in small, colourless scales melting a t 12So, A number of preparations were polarimetrically examined in acetone solution, but all were optically inactive : CH.?>s<I 0.3256 gave 0.1922 Hg12.HgI, = 59*02. 0.1615 ,, 0.0920 HgI,. HgI, = 57.94. C,,H1,OI,SHg requires HgI, = 58.50 per cent. Metl~yIethylphen~ylthetin~ Mercwichloride, CH, C1 C2H5>S<CH2*C0 CGH,, Hg CI,. The optically inactive mercurichloride is prepared by adding an aqueous solution of potassium chloride and mercuric chloride to one of a salt of the d-, I - , or externally compensated thetine, and crystallising the precipitate from dilute alcohol ; it forms glistening, white scales melting at 119") and is insoluble in water or ether but dissolves in alcohol or acetone.The preparations obtained from the three sources were identical and were optically inactive in acetone solution : C1= 21.46. 0.2162 gave 0.0464 C1 on titration. 0.3114 ,, 0.0669 CI 1 ) C1= 21.48. C,,H,,OCl,SHg requires C1= 21.23 per cent. The fact that methylethylphenylselenetine mercuriodide and methyl- ethylphenacylthetine mercuriodide and mercurichloride are all three obtained as optically inactive substances from salts of t h e optically active selenetine or thetine must be regarded RS proof that optical1560 POPE AND NEVfCLE : ASYMMETRIC inversion actually does take place during their formation, for i t can hardly be supposed that the three different substances are really optically active but happen to possess specific rotatory powers so small as to have evaded detection, The non-occurrence of optical inversion when d- and I-benzyl- phenylallylmethylammonium salts are converted into their mercur- iodides led Pope and Harvey (Trans., 1901, 79, 840) to regard as improbable the suggestion that nitrogen is septavalent in such com- pounds and also, by analogy, that the sulphur in sulphonium mercur- iodides is sexavalent ; the facts now brought forward, however, necessitate a revision of this view.If, as was suggested by Smiles for the sulphonium mercuriodides (Trans., 1900, 77, 160), the quadri- valent sulphur or selenium atom in sulphonium or selenonium salts become sexavalent during the formation of the mercuriodides, the latter have the following constitutions : *\ /OR3 and I-Se-C,H5 I\ /"H3 I-S-C,H, I H ~ / \CH,.CO-C,H, IHg/ \CH,*CO,H ' The simplest environment of the sexavalent atom would be one in which the six atomic groups are situated on three lines drawn at right angles to each other through'the sexavalent atom, the six groups being thus situated a t the apices of an octahedron of which the sexavalent atom occupies the centre, The most symmetrical manner in which the two new atomic groups can enter the original tetrahedral configuration during its conversion into the octahedral one results in their occupying diametrically opposite vertices of the octahedron, and if this occurs, the four groups a, b, c, and i , which are originally tetrahedrally distributed (Fig.1, p. 1561), necessarily fall into the same plane as the central sulphur or selenium atom a t the moment when the two new groups, i and h, become joined on (Fig.2). But as the groups a, 6, c, and i fall into a plane with the sulphur or selenium atom, the enantiomorphism due to their distribution simultaneously disappears and an optically inactive product yould therefore probably result. A less symmetrical method of inserting the two groups, i and h, in the original compound, which leads, how- ever, to an octahedral configuration of higher symmetry than Fig. 2, is illustrated by Fig. 3 ; this is a non-enantiomorphous configuration, and if i t represents the mercuriodides, the latter would necessarily be optically inactive. The other possible configurations of the sexavalent sulphur or selenium compounds need not be now discussed; i n their formation, the groups h and i require to be inserted in a very unsym- metrical manner and the product would have a highly unsymmetrical configuration.That they should be produced seems improbable inOPTICALLY ACTIVE SELENlUM COMPOUNDS. 1561 view of the tendency towards the formation of symmetrical products in chemical reactions. During the conversion of a quinquevalent into a septavalent nitrogen atom, unless in the resulting substance the original five groups lie in the same pIane as the nitrogen atom, there is no reason to expect the five groups to lose their enantiomorphous arrangement or for the two new atomic groups t o assume such positions in the PIC. 1. U C F I G . 2. FIG. 3. i 2 molecule as to give rise to a non-enantiomorphous product ; these are the two cases analogous to those illustrated in Figs.2 and 3. Although the intramolecular disturbance attending a change of valency might be expected to cause optical inversion, there is no reason to anticipate the existence of a non-enantiomorphous configura- tion at any moment during the formation of a septavalent nitrogen compound from an optically active substituted ammonium salt, if the transition from quinque- to septa-valency occurs by some orderly series of mechanical steps. We know, in fact, that the asymmetric1562 ASYMMETRIC OPTICALLY ACTIVE SELENIUM COMPOUNDS. ammonium iodides preserve their optical activity during formation of the mercuriodides. The explanation thus offered seems rational and involves the principle enunciated by Pope and Harvey (Zoc. cit.), that during a change of valency the valency directions may change.Since the evidence now brought forward inclines us not to regard the above mercuriodides as salts of the complex acid HHgI, whilst we still consider the platinichlorides as salts of the acid H,PtCI,, it seemed desirable to attempt some experimental discrimination between the configurations represented in Figs. 2 and 3. If the acid HHgI, is not a factor in determining the formation of the mercur- iodides, the production of these salts would seem due to the use of a mercuric compound and the particular acidic groups associated with the metal would not be so likely to influence the formation of a sexavalent sulphur compound ; it should therefore be possible to prepare salts corresponding to the mercuriodides and mercurichlorides in which the three halogen groups are replaced by three optically active acidic groups.Then, if the new salt have the configuraticn given in Fig. 2, or if it be merely a salt of the acid HHgX, (X being the optically active group), fractional crystallisation should show it to be a mixture of the two substances (d-B, d-A, Hg2d-A) and (Z-B, d-A, Hg2d-A), whilst if Fig, 3 represent the constitution and configuration of the new salt, the latter must be a single sub- stance, potentially irresolvable, and its molecular rotatory power in aqueous solution should be of the order of thrice that of the optically active acid ion. The view taken above of the constitution of the mercuriodides is supported by the fact that we were able to prepare the following salt.Methyletlzyl~henncylthetine Merczcri-d-bromocamh~suZ~~onate, S( CH,) (C,H,) (CH, CO C,H,) ( CloH1,OBr SO,H),Hg CloH1,OBr*SO,H. On adding a concentrated solution of mercuric oxide in d-bromo- camphorsulphonic acid to an aqueous solution of Z-rnethylethylphen- acylthetine d-bromocamphorsulphonate, a white precipitate is produced which, after crystallisation from dilute alcohol, is obtained in minute, white scales decomposing a t about 1 8 0 O ; it is insoluble in ether or chloroform but sparingly soluble in water, acetone, or alcohol : 0.4512 gave 0.07855 HgS. Hg = 14-98. C,,H,701,Br,S4Hg requires Hg = 15.23 per cent. After several recrystallisations, 0.3300 gram, made up to 25 C.C. with water, gave aD -!- l"37' in a 2 dcm. tube; whence [a], 4-60.9' and [MID + €looo. Within the limits of experimental error, this value is equal to +SIOo, three times the molecular rotatory power of theHYDROXYOXAMIDES. PART 11. 1563 d-bromocamphorsulphonic ion, A preparation made from d-methyl- ethylphenacylthetine d-bromocamphorsulphonate, after careful purifica- tion, proved to be identical with the foregoing. 0.3512 gram, made up to 25 C.C. with water, gave uD + 1'43' in a 2 dcm. tube, whence [ u ] ~ + 60.S" and [MID + 798". Although further investigation of this salt is needed and is nuw in progress, the facts that the preparations from the d- and 2-thetine salts yield fractions having practically the same rotatory power, and that that rotatory power is very nearly thrice the molecular rotatory power of the optically active acid ion, indicate that the two sources yield the same'and a single irresolvable product, and that the sexa- valent sulphur.atom is not a centre of optical activity because it con- tributes no appreciable amount t o the molecular rotatory power of the mercuri-d-bromocamphorsulphonate. The configuration of the thetine and selenetine mercuriodides and mercurichlorides would therefore seem to be that illustrated in Fig 3. CHEMISTRY DEPARTMENT, MUNICIPAL SCHOOL OF TECHNOLOGY, MANCIIESTER.

ISSN:0368-1645    

DOI:10.1039/CT9028101552

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

HYDROXYOXAMIDES. PART 11. 1563 CLV1.-Hydroxyoxamides. Part 11. By ROBERT HOWSON PICKARD, CHARLES ALLEN, WILLIAM AUDLEY BOWDLER, and WILLIAM CARTER. SCHIFF AND MONS ACCHI (Anncclen, 1895, 288, 31 3) hydrolysed oxa- methane with hydroxylamine, and obtained a compoand to which they gave the name ‘‘ hydroxylamide,” and ascribed the formula, NH,*CO*CO*NH*OH. At the same time, they pointed out that it de- composed at the same temperature as, and was very similar to, the compound obtained by Holleman (Rec. truv. chim., 1894, 13, 84) by the action of hydrochloric acid on oxamidedioxime. Holleman then compared the two substances (Rec. trav. chim., 1896, 15, 148), showed that they were not identical, and suggested that they were stereoisomerides of the formula NH,*C(NOH)*CO*OH. H e gave the syn-formula t o his own compound, since this more readily explains the formation of cyanamide when it is treated with acetic anhydride.The anti-configuration was given t o Schiff and Monsacchi’s compound, as this more readily accounts for the formation of carbon dioxide and carbamide when it is heated. In 1901, it was shown by Pickard and Carter (Trans., 79, 841) that1564 PICKARD, ALLEN, BOWDLER, AND CARTER : the compounds obtained when oxamethane and the oxamates, R-NH=CO*CO,Et, are hydrolysed with hydroxylamine, react as hydr- oxamic acids, the acetyl derivatives yielding biurets and allophanates, in accordance with the reactions of hydroxamic acids described by Thiele and Picknrd (Awnden, 1899, 309, 189). Schiff (Annalen, 1902, 321, 357), however, although acknowleclging that these reactions are best explained by the hydroxyoxamide formula, NH;CO-CO*NH*O€I, or R*NH*CO*CO*NH*OH, ascribed the amid- oxime formula, NH,*C(NOH)*CO*OH, to the compound obtained by the hydrolysis of oxamethane, basing this opinion mainly on some titration experiments, which apparently showed that the compound in question behaved on titration like an amino- or amido-acid (compare Schiff, AlenaZen, 1901, 319, 59).We have reinvestigated these compounds, and now bring forward fresh evidence in favour of the Several new hydroxyoxamides have been prepared, namely, o-tolyl, 0-, m-, and p-nitrophenpl and ethyl-hydroxyoxamides, and they all give the various reactions of hydroxamic acids (compare Zoc. cit.). The ethylhydroxyoxamide is of interest as it shows that the method which has yielded the substituted biurets with an aromatic radicle will also yield those with aliphatic radicles.The latter are not obtained when ethyl allophanate is treated with aliphatic amines (Hofmann, Bey., 1871, 4, 265). One mol. of a hydroxyoxamide, when dissolved in water or alcohol, is neutralised by 1 mol. of potassium hydroxide, We were unable to repeat under very varied conditions the experiments described by Schiff (Zoc. cit.), in which hydroxyoxamide w3.s neutralised by the calculated quantity of potassium hydroxide only after treatment with formaldehyde, using phenolphthalein as indicator. When an oxamate is hydrolysed with 2 mols. of hydroxylamine, the hydroxylamine salt of the hydr- oxamic acid is first obtained, and it is possible that the hydroxyoxamide used by Schiff in his titration experiments mas contaminated with the hydroxylamine salt.Hydroxyoxamide, when neutralised with ammonia and treated with a solution of silver nitrate, yields a colourless, stable silver salt ; it is significant that in Schiff and Monsacchi’s paper it is stated that the hydroxyoxamide is crystallised from water, whereas the silver salt is only stable when prepared from a product which has been either crystallised five or six times from water or once from dilute acetic acid. Hydroxyoxamide decomposes violently at 15 So without melting, and it is noteworthy that products containing traces of the hydroxylamine salt decompose at about the same temperature. Various types of hydroxamic acids have been titrated with decinormal solutions of caustic alkalis, using phenolphthalein as the indicator, and it has been found that they all give approximately quantitative results. hydroxyoxamide ” formula.HYDROXYOXAMIDES.PART I i . 1565 The silver salts of hydroxyoxamide and phenylhydroxyoxamide, when treated with ethyl iodide, yield esters which behave as monobasic acids when titrated with caustic alkalis. It is very difficult to understand how esters with an acid reaction could be obtained from a substance having the amidoxime constitution, NH,*C(NOH)*CO,H, since the groups NH,*C(NOH)- and R*NH-C(N0H)- have a basic or neutral function, the amidoximes, C,H,*C(NOH)*NH, and C,K,*CH(OHj*~(NOH)*NH,, being neutral substances. The esters of hydroxamic acids, R.C(OH):N*OEt, on the other hand, are acid by virtue of their tautomeric hydrogen atom, b&g soluble in caustic alkalis and re- precipitated by carbon dioxide.The hydroxyoxamides, R*NH*CO*CO*NH*OH, when treated with aniline, yield anilides of the type R*NH*CO-CO*NH*C,H,, and when treated with a n alcoholic solution of phenylhydrazine form phenyl- hydrazides of the type R*NH*CO*CO*NH*NH*C,H5. These two re- actions, which are approximately quantitative, are also given by hydroxamic acids, and afford strong evidence against such formulae as NH,*C(NOH)*CO,H for hydroxyoxamide (arnidoximeoxalic acid), or CO,H*C( NOH)*NH* OH for malondih y droxamic acid (hy droxamoxime- malonic acid). Ulpiani and Ferretti (Gaxxetta, 1902, 32, i, 205) have shown that hydroxyoxamide is obtained when nitromalonamide is treated with concentrated sulphuric acid.They formulate the course of the reaction as follows : NH,*CO*CH(NO,)*CO~NH, - NX,*CO*CH,*NO, - NH,*CO*CH:NO*OH -. NH,*CO*C'(OH):NOH. This reaction affords further evidence in favour of the hydroxamic nature of these compounds, and is entirely opposed t o formulae of the type NH,*C(NOH)*CO,H. A reinvestigation of the amidoximeoxalic acid, NH,*C(NOH)*CO,H, confirms its general rroperties as described by Holleman (Zoc. cit.). It behaves as a monobasic acid when titrated with potassium hydroxide, the acidity of the carboxyl group not being masked by the NH, group as inferred by Schiff. Moreover, it forms a stable, crystalline ester which is neutral, thus differing from the esters of the hydroxyoxamides.To sum up, therefore, these hydroxyoxamides behave in all respects like typical hydroxamic acids, and there is not the slightest evidence in favour of the amidoxime constitution. E XPE R I M E N:T A L. Hydroxyoxccmide, NH,*CO*CO*NH*OH or NH,*CO*C(OH):NOH. When oxamethane is hydrolysed with hydroxylamine either in aqueous or alcoholic solution, at any temperature from 0' t o loo", a mixture of hydroxyoxamide and its hydroxylamine salt is obtained.1566 PICKAHD, ALLEN, BOWDLElt, AND CARTER: . A product, which separsted out when saturated aqueous solutions of oxamethane (1 mol.), hydroxylamine hydrochloride (2 mols.), and sodium carbonate (1 mol.) were mixed at 60°, contained NaC1=21*08; N=22.68 per cent. This analysis showed that 28.73 per cent.of the organic matter in the product was nitrogen, whereas the pure hydroxyl- amine salt of hy droxyoxamide, NH,*CO* CO*NH*OH,NH,OH, contains N = 30.65 per cent. 0.104 Gram (1 mg.-mol.) of hydroxyoxamide, after recrystallisation from dilute acetic acid, when dissolved in alcohol or water, either at the ordinary temperature or warm, nentralises approximately 10 C.C. of N/lO potassium or barium hydroxide solution, using phenol- phthalein as indicator. I n no case did the addition of formaldehyde alter the titrations, and in every case the usual coloration was given by the solution with ferric chloride, both before and after titration. Silver Xcdt.-An aqueous solution of pure hydroxyoxamide is exactly neutralised with dilute ammonia, and then precipitated with a solution of silver nitrate.The silver salt, when first precipitated, is slightly yellow, but rapidly becomes white,is quite stable when dry, and explodes when heated. Ethyl Ester, NH,* GO* C( OH):N*O* C,H,.-The silver salt suspended' in ethyl alcohol is boiled under a reflux condenser with the calculated quantity of ethyl iodide for three hours. After filtering off the silver iodide, the solution is evaporated to dryness and the resulting product crystallised from alcohol. The ester is thus obtained in star- shaped clusters of pearly lamins which melt at 178'. It is not affected by boiling water and is only slightly hydrolysed by warm solutions of hydroxylamine. 0:132 Gram (1 mg.-mol.) dissolved in water required 10 C.C. of N/10 potassium hydroxide solution for neutralisation with phenol- phthalein as indicator : 0.0712 gave 13 C.C.moist nitrogen at 15' and 752 mm. N = 21.12. C,H80,N, requires N = 2 1-2 1 per cent. Oxanzphenylhydracaide, NI3,*COoCO0NH*NH~C,H,.-An alcoholic solution of phenylhydrazine and hydroxyoxamide is boiled under a reflux condenser €or two hours. . The phenylhydrazide crystallises out from the solution on cooling, and the crystals, after successive washings with acetic acid and sodium carbonate solution and recrys- tallisation from alcohol, melt at 231O." ' Acet ylhydroxyoxamide, NH,*CO* C( OH): "0. COO CH, (Schiff and Monsacchi, Zoc. &.).-A cold aqueous solution of 0.146 gram (1 mg.- mol.) was neutralised by 11 *6 C.C. of N/ZO potassium hydroxide solution, partial hydrolysis having taken place.* Schleussner (Inaug. Diss., Munich, 189'1), gives the melting point as 230-233'. .HYDROXY OXAMIDES, PART 11. 1567 When boiled with dimethylaniline, the acetyl derivative is quanti- tatively converted into carbamide. Plienylliydrox~oxaxccmide, C,H,*NH*CO*C(OH):NOH. 0.1 80 Gram (1 mg.-mol.) of phenylhydroxyoxamide (Schiff and Monsacchi, loc. cit.) is neutralised by 10 C.C. of N/10 potassium hydroxide solution. Phenylhydroxyoxamide, when warmed with aniline, yields oxanilide, and when boiled with an alcoholic solution of phenylhydrazine yields oxanilphenylhydraxide, C ~ ~ ~ = N H * C O * C O * ~ H * N H * C ~ H ~ . ~ This crys- tallises from glacial acetic acid in clusters of stellate needles, and melts and decomposes at 228'. It is insoluble in a solution of sodium carbonate, gives Bulow's reaction, and reduces Pehling's solution : 0.2525 gave 36.7 C.C.moist nitrogen at 15' and 744 mm. N = 16.65. 'The silver salt and ethyl ester mere prepared as described under The silver salt is obtained as a white, amorphous precipitate, and The ester crystallises from alcohol in coIourless, silky needles which It is soluble in potassium hydroxide solution and is 0.208 Gram (1 mg.-mol.) dissolved in alcohol neutralised 10.1 C.C. of Cl,H1,O,N, requires N = 16.47 per cent. the analogous derivatives of hydroxyoxamide. leaves metaIIic silver on ignition. melt a t 176". reprecipitated by carbon dioxide. XI10 potassium hydroxide solution : 0.1111 gave 13.5 C.C. moist nitrogen a t 22' and 750 mm. N- 13.58. C,,,Hl,O,N, requires N = 13-46 per cent.Phenylacetylhydroxyoxamide, when boiled with pyridine, decom- poses violently, evolves carbon dioxide, and gives a .solution which, when thrown into water, yields a mixture of phenyl- and s-diphenyl- . car bamides. The three nitro-phenyl-, o-tolyl-, and ethyl-hydroxyoxamides, their acetyl derivatives, and transforma tion products have been prepared from the corresponding oxamates by analogous methods to those pre- viously described (Zoc. cit.). hy drazide. * Oxanilic acid, when treated under similar conditions, yielded only traces of1568 PICKARD, ALLEN, BOWDLER, AND CARTER : o- Nitrophenylhydroxyoxa~id~ and Derivcdues. Ethyl o-nitrophenyloxamaie, NO,- C6H4*NH*CO*C02*C2H5, is obtained by the condensation of ethyl oxalate (1 mol.) and o-nitroaniline (1 mol.). It crystallises from alcohol or acetic acid in pale yellow needles and melts at 113O : 0.1257 gave 13.4 C.C.moist nitrogen at 22' and 752 mm. N = 11.93. Cl,H1,O,N, requires N = 11 *76 per cent. o-iVitropheny Zhydroxyoxamide, NO,* C,H,*NH GO* CO* NH*OH, cry s- tallises from glacial acetic acid in silky, white needles which melt and decompose at 153O : 0.1400 gave 22.3 C.C. moist nitrogen at 18.5' and 756 mm. N = 18.24. 0.225 Gram (1 mg.-mol.) dissolved in warm alcohol neutralised 10.6 C.C. of N/10 potassium hydroxide solution. The sodium, potassium, ammonium, and hydroxylamine salts are yellow, crystalline substances, of which the last melts at 161'. The acetyl derivative, NO,*C,H,*N H*CO*C(OH) *NO*CO°CH,, crjs- tallises in colourless, silky needles from acetic acid and melts at 160'.When boiled with sodium carbonate solution, it is completely decom- posed, yielding o-nitroaniline : 0.2348 gave 32.7 C.C. moist nitrogen at 21° and 756 mm. N = 15.76 Cl,H,06N, requires N = 15.73 per cent. o-Nitrophenylbiuret, NO,* C,H,*NH*CO*NH*CO*NH,, crystallises from hot water in beautiful, long, canary-coloured needles which melt at 181O: C,H70,N, requires N = 18-66 per cent. 0.1644 gave 37.1 C.C. moist nitrogen at 25' and 764 mm. N = 25.31. C,H,O,N, requires N = 25.00 per cent. o-Nitro-ozan~tphenylhydraz~de, N02*C6H, H* CO*CO*XH NH*C,H,, crystallises from acetic acid in small, yellow needles which melt and decompose at 1 8 1 O . It reduces Fehling's solution and gives Bulow's reaction : 0.0827 gave 13.7 C.C. moist nitrogen at 25' and 757 mm.N = 18.40. C,,H,,O,N, requires N = 18.66 per cent. m-Nitrophsnylhydroxyoxamide and Derivatives. m-Nitrophenylhydroxyoxamide, NO,* C,H,*NH* COO CO*NH* OH, cry s- tallises from acetic acid in colourless, silky needles which melt and decompose at 161O :HYDROXYOXAMIDES, PART 11. 1569 0.1517 gave 24.1 C.C. moist nitrogen at 15' and 757 mm. N = 18.44. 0.225 Gram (1 mg.-mol.) dissolved in alcohol was neutralised by The hydyoxglamine salt was obtained as a jelly which became crys- It crystallises from anhydrous alcohol in lustrous, The C,H70,N, requires N = 18*66 per cent, 10 C.C. of N/10 potassium hydroxide solution. talline on shaking. silky, yellowish needles and melts and decomposes at 188'. sodium, potassium, and ammonium salts are yellow.m- Nitrophen ylncet y Zh ydroxyoxcmide, NO,*C,H;NH*CO~C(OH):NO*CO*CH,, crystallises from acetic acid in white, silky needles which melt and decompose a t 184'. It is only slightly soluble in alcohol or chloroform : 0,1482 gave 20.8 C.C. moist nitrogen a t 22' and 761 mm. N = 15.91. C,,H,O,N, requires N = 15.73 per cent. The sodium and potassium salts are yellowish, crystalline compounds. The ammonium salt crystallises from alcohol in small, yellow, prismatic needles which melt and decompose at 150'. Carbonyl di-m-nitrophenylcarbamide, CO(NH*COoNH*C,K,*NO,),, crystallises from water in golden-yellow needles. It melts and decom- poses a t 142' : 0*1038 gave 20.3 C.C. moist nitrogen at 24O and 760 mm. N=21.93. CT,,Hl2O7N, requires N = 21.64 per cent. m-Xitrophenylbiuret, N0,*C,H40NH*CO*NH~CO*NH,, separates from a mixture of water and alcohol in canary-yellow crystals melt- ing at 178".0.0672 gave 14.4 C.C. moist nitrogen at 21O and 760 mm. N = 24.40. C,H,O,N, requires N = 25.00 per cent. ElhyZ m-nitrophenylallophanate, NO,*C,H,*NH~CO*NH*CO,*C,H,, crystallises from alcohol in yellowish, silky needles, which melt at 188'. I t is soluble in potassium hydroxide solution, and is reprecipi- tated by acids : It is slightly soluble in a solution of sodium hydroxide : 0.0850 gave 13 C.C. moist nitrogen at 24' and 744 mm. N= 16.77. C,,HllO,N, requires N = 16.60 per cent. m-Nitro-oxani~henyZ/~ydraxide, NO2*C,H,*NH*CO.CO*NH.NH.C,H5, crystallises from alcohol in glistening, yellow lamina?, melts at 1 8 4 O , and reduces Fehling's solution : N = 18.48.0.0791 gave 13 C.C. moist nitrogen a t 20° and 749 mm. C,,Hl,O,N, requires N = 18.66 per cent. m-Hitro- oxanilide, NO,* C6H4' NH CO CO NH. C,H,, is obtained by VOL. LXXXI. 5 N1570 PICKARD, ALLEN, BOWDLER, AND CARTER : heating the hydroxyoxamide with aniline at 170' for four hours. It crystallises from nitrobenzeue in yellowish, prismatic needles which melt at 204': 0.1530 gave 20.6 C.C. moist nitrogen a t 24' and 756 mm. N= 15.00. C1,H,,04N3 requires N = 14-73 per cent. p- NitropAenyl~~ydroxyoxamide and Derivatives. Ethyl p-nitrophenyloxamacte, NO,*C,H,*NH*CO C0,*C,H5, crystal- 0.1813 gave 18.8 C.C. moist nitrogen at 22' and 764 mm. N=11a80. CloMlOO5N2 requires N = 11.76 per cent. p-Nitrophenylhydroxyozamide, NO,*C,H,*NH*CO*CO*NH*OH, crys- tallises in colourless needles from glacial acetic acid and melts at 182' : 0.1142 gave 18.8 C.C.moist nitrogen at 19' and 756 mm. N = 18.78. C,H,05N3 requires N = 18-66 per cent. 0.225 Gram (1 mg.-mol.) dissolved in alcohol required 9.8 C.C. of NIT0 potassium hydroxide solution for neutralisation. The hydroxylamine salt is a pale yellow, crystalline substance melt- ing at 190'. The acetyl derivative, N0,*C,H4*NH*CO*C(OH):NO*CO*CH3, crys- tallises from acetic acid in silky, white needles melting with decompo- sition a t 182' : 0.1923 gave 26.8 C.C. moist nitrogen at 22' and 756 mm. N= 15.67. lises from acetic acid in white, prismatic needles and melts at 166' : . CloH,O,N, requires N = 15.73 per cent. It is completely decomposed when boiled with dilute sodium car- bonate solution, yielding p-nitroaniline.p-Nitrophenylbiuret, N0,*CGH,.NH*CO*NH*CO*NH2, crystallises from water in pale golden-yellow needles with water of crystallisation. It melts a t 206' and is very soluble in alcohol. NO,* C6H4 NH CO NH CO, C,H,, crystallises from alcohol in white, silky needles which melt and decompose at 220° : N = 16.59. Eth y I p-nitrophenyla llophanat e, 0.0604 gave 8.8 C.C. moist nitrogen at 1s' and 751 mm. p-ffitro-oxcarti~~~enyZhydraxide, ~ 0 , ~ C , H 4 * ~ ~ ~ ~ O ~ C O ~ ~ ~ It melts CloHl,O,N, requires N = 16.60 per cent. crystallises from alcohol in flat, compact, yellow needles. and decomposes a t 217' and reduces Fehling's solution : 0.1599 gave 25.6 C.C. moist nitrogen at 15' and 750 mm. N = 18.52. C,,H,,O,N, requires N = 18.66 per cent.HYDROXYOXAMIDES, PART 11.1571 o-Tolylhydroxyoxamide and Derivatives. Ethyl o-tolyloxamate, CH,-C',R,*NH~CO*CO,*C,H,, is erroneously described in Beilstein as a substance melting a t 130' when anhydrous. Such a substance is a mixture of the oxamide and oxamate. The two are separated by extraction with ether, in which the oxamate is much the more soluble. It crystallises from dilute alcohol and melts a t 40' : N=7*18. 0.2926 gave 18.8 C.C. moist nitrogen at 21' and 748 mm. CllHI,03N requires N = 6.76 per cent. o-Tolylhydroxyoxamide, CH~*C,H,*NH*CO*CO*NH*OH, crystallises from dilute acetic acid in star-shaped clusters of needles and melts at 152' : 0.1880 gave 23.8 C.C. moist nitrogen at 20' and 756 mm. N= 14-44. C,H,,O,N, requires N = 14.44 per cent.The acetyl derivative crystallises from acetic acid in needles and 0.1133 gave 12 C.C. moist nitrogen at 19' and 754 mm. It is very easily soluble in alcohol. melts a t 125': N= 12.07. C11H,,04N2 requires N = 11 W.5 per cent. The ammonium salt crystallises from alcohol in Iustrous, silvery plates which melt with decomposition at 139". The sodium salt is a microcrystalline powder which begins to decompose a t about 120'. Ctcrbonyldi-o-tolylcarbumide, CO(NH*CO*NH*C6H,*CH,)z, crystal- lises from alcohol in needles and melts a t 190' : 0.0740 gave 11 C.C. moist nitrogen a t 19' and 756 mm. N= 17.04. C17H,,0,N, requires N = 17.17 per cent. EthyE o-toZyZaEZophanate, CH,*C,H,*NH*CO*NH*C02-C2H5, crysta1- 0.2819 gave 31 *3 C.C. moist nitrogen a t 195'and 758 mm.N = 12.65. o-Tolylbiuret, CH3* C,H,*NH*CO*NX*CO *NH2, separates f porn 0.0894 gave 17 C.C. moist nitrogen at 20' and 758 mm. N=21*67. lises From dilute alcohol in needles and melts a t 137' : C,,H,,O,N, requires N = 12.61 per cent. alcohol as a microcrystalline powder which melts at 180' : CSHl,O,N, requires N = 31 -76 per cent.1572 PICKARD, ALLEN, BOWDLER, AND CARTER : Ethylhyd.roxyoxanLide and J)e.riuativee. Ethylhydroxyoxumide, C,H,*NH*CO*CO*NH*OH, crystallises from ether in colourless lamins, melts a t 138', and is very soluble in most organic solvents. 0.132 Gram (1 mg.-mol.) of the product extracted by ether from the acidified aqueous solution of its hydroxylamine salt was neutralised by 8.6 C.C. of N/10 potassium hydroxide solution. The hydrozylarnine salt crystallises from alcohol in small, white, glistening needles melting at 156' : 0.0705 gave 16:c.c.moist nitrogen at 21' and '756 mm. N=25.65. C,H,,O,N, requires N = 25.45 per cent. The acetyl derivative,. C2H,*NH*CO-C(OH):NO*CO*CH3, crystal- lisea from acetic acid in lustrous, colourless needles which melt a t 138' : 0.1071 gave 15.5 C.C. moist nitrogen at 20' and 744 mm. N = 16.24. C,H,,O,N, requires N = 16.09 per cent. Ethylbitwet, C,H,*NH*CO*NH.CO*NH,, crystallises from water in star-shaped clusters of prismatic needles. These melt at 153' and decompose violently a few degrees higher : 0.0447 gave 13 C.C. moist nitrogen a t 22' and 748 mm. N = 33.32. C,H,02N, requires N =I 32.06 per cent. . Hydi*oxamic Acids. Omldihydroxamic Acid, (CO~NH*OH),.-0*120 Gram (1 mg.-mol.) of oxaldihydroxamic acid (Hantzsch and Urbahn, Ber., 1894, 27, 801) dissolved in warm water was neutralised by 18.6 C.C.of N/10 barium hydroxide solution. When boiled with an alcoholic solution of phenyl- hydrazine, a quantitative yield of oxaldiphenylhydrazide (m. p. 278') was obtained. Malondihydvoxamic Acid, CH,( CO*NH*OH),,-This was prepared according t o Hantzsch and Urbahn's method (Zoc. cit.), who give the melting point as 154-1.55'. H. Schiff (loc. cit.) states that the purest specimen he obtained melted at 144-145'. We found it to cryetallise from dilute acetic acid in square plates melting at 1609" (Nitrogen found, 21.08 per cent. ; calc., 20.89 per cent.) 0.134 Gram (1 mg.-mol.) dissolved in dilute alcohol neutralised 18.5 C.C. of N/lO barium hydroxide solution. * In crptallising these and similar products, it is advisable to drop the powdered ammonium or hydroxylamine salt into dilute acetic acid which has been previously warmed ; on cooling, the free acid separates out.Boiling with dilute acetic acid often decomposes these hydroxamic acids.HYDROXYOXAMIDES. PART rI. 15'73 When boiled with an alcoholic solution of phenylhydrazine, malon- dihydroxamic acid yields malondiphenylhydrazide (m. p. 186'). Benxhydroxamic Acid, C,H,*CO*N€€*OH.-O*l37 Gram (1 mg.-mol.) dissolved in alcohol gave a coloration with phenolphthalein after the addition of 5.2 C.C. of XI10 potassium hydroxide solution. This is due to the formation of the salt C,H,~C(OH):NOH,C,H,*C(OH)*NOK described by Lossen (Annalen, 1872, 161, 347).0.137 Gram (1 mg.-mol.) dissolved in alcohol was neutralised by 9.7 C.C. of N/10 barium hydroxide solution. Benzhydroxsmic acid, when boiled with an alcoholic solution of phenylhydrazine, yields benzoylphenylhydrazine (m. p. 169O). Milligram-mols. of dibenzhydroxamic acid, acetylbenzh ydroxamic acid,* benzoylpyromucylhydroxamic acid (Trans., 1901, 79, 847), and p-tolylacetylhydroxyoxamide (Zoc. cit .) were all neutralised by 9.9-10 C.C. of XI10 potassium hydroxide solution. One mg.-mol. of methyleneamidoxime-acethydroxamic acid, NH,*C(NOH)*CH,*CO*NH*OH (Modeen, Ber., 1891, 24, 3437), was neutralised by 9 C.C. of N/10 barium hydroxide solution. Oxamates of the type NRR*CO*CO,*C,H, are hydrolysed by an alcoholic solution of hydroxylamine, giving the secondary amine and oxaldihydroxamic acid.This was proved in the case of ethyl methyl- oxanilat e, I" ethyl eth y loxanila te, and ethyl pi peridy Ioxamat e. The following hydroxamic acids were prepared for the purpose of Pyr.uvyl~iaenyliiydraxone~ydroxacmic acid, comparison. CH,*C( N*NH* C,H,)*CO *NH*OH, was obtained by treating the corresponding ester with an alcoholic solution of hydroxylamine and was isolated by means of i t s lead salt. It crystallises from a mixture of ethyl acetate and benzene in white needles which melt a t 148". It is very soluble in alcohol, acetone, or ethyl acetate, but only slightly so in ether : 0.0901 gave 16.8 C.C. moist nitrogen a t 16' and 750 rum. N=21.45 0.193 Gram (1 mg.-mol.) dissolved in alcohol was neutralised by 10 C.C.of N/lO barium hydroxide solution : * Acetylbenzhydroxamic acid, when boiled with pyridine, gives a solution whioh when thrown into water, yields s-diphenylcarbamide. .t. These oxamatev mere prepared by heating ethyl oxalate (1 rnol.) and the amine (1 mol.) in an oil-bath at 150" for 4-5 hours. The products were washed with dilute sulphuric acid to free from excess of the amine, dried, and fractionated. Ethyl ethyloxsnilate, C,H,'N(C2H,)'CO'C0,'C,H,, is a pale yellow oil which boils C,Hl1O,N3 requires N = 21-76 per cent. at 215-220",1514 HYDROXYOXAMIDES. PART 11. The acetyl derivative crystallises from dilute acetic acid in colourless 0.1053 gave 16.2 C.C. moist nitrogen a t 16' and 750 mm. N=17.73. C,lH,,O,N, requires N = 17-87 per cent. The ammonium and sodium salts are soluble in alcohol, and the sub- stance is entirely decomposed by boiling with pyridine or dimethyl- aniline, needles which melt at 113'.P~enyZgZycinehyd~oxGlmic acid, C,H,*NH*CH,*CO*NH*OH. An alcoholic solution of hydroxylamine is prepared in the usual way, and when quite cool the equivalent quantify of ethyl anilino- acetate (Bischoff and Hausdorfer, Ber., 1892, 25, 2270) is added. On the addition of sodium (I mol. dissolved in alcohol), an almost quantita- tive yield of the sodium salt of the hydroxamic acid is obtained. This is filtered off, dissolved in water, and the hydroxamic acid set free by the addition of the exact quantity of dilute sulphuric acid re- quired, The white precipitate is filtered off and crystallised from dilute alcohol.The hydroxamic acid is thus obtained in the form of colourless, small, glistening plates which melt and decompose at 118' : 0.1688 gave 0.3580 GO, and 0.0923 H20. 0.2280 ,, 34.7 C.C. moist nitrogen a t 20' and 736 mm. N= 16.84. 0.166 Gram (1 mg.-mol.) dissolved in alcohol was neutralised by 10.3 C.C. of N/lO barium hydroxide solution. Phenylglycinehydroxamic acid is soluble in alcohol, but only slightly so in ether, benzene, or water. It is dissolved and decomposed by dilute mineral acids. Its aqueous solution gives the usual coloration with ferric chloride. Acety? Derivative.-The hydroxamic acid is extremely difficult to acetylate owing t o its extraordinary sensitiveness towards acids. It waR therefore dissolved in pyridineand kept cool while the calculated quan- tity of acetyl chloride was slowly added.The mixture, after standing overnight, was poured into water, and the resulting precipitate crys- tallised from alcohol. The acetyl derivative was thus obtained in the form of long, colourless, prismatic needles melting at 1079 It is insoluble in ether and has an acid reaction toward litmus : 0.1375 gave 16.5 C.C. moist nitrogen at 20' and 745 mm. N = 13.45, On neutralising an alcoholic solution with sodium ethoxide, the C = 57.84 ; H = 6.07. C,H,,O,N, requires C = 57.83 ; H = 6.02 ; N = 16.86 per cent. C,,H,,O,N,:requires N = 13.46 per cent.TEE CONSTITUENTS OF COMMERClAL CHRYXAROBIN. 1578 sodium salt is precipitated. warming its aqueous solution. ing the acetyl derivative with sodium carbonate or dilute ammonia. This salt slowly decomposes to a n oil on No better result is obtained on treat- Amidoximeoxalic Acid. 0.104 Gram (1 mg.-mol.) of amidoximeoxalic acid (Holleman, Zoc. cit.) dissolved in approximately 30 C.C. of water a t 20' required 9.4 C.C. of R/ 10 potassium hydroxide solution for neutralisation. Ethyl Eater, NH,*C(NOH)*CO,*C,H,.-The silver salt suspended in alcohol is boiled with the calculated quantity of ethyl iodide, The alcohol is then evaporated off and the oily mass extracted with ether. The ester separates from the ether in colourless, lustrous needles. These melt at 97-98O and evolve gas a t 140-170°, a t which tempera- ture entire decomposition sets in. The ester is soluble in water, alcohol, or ebher, and i t s solutions are completely neutral to litmus, and give a sienna-brown coloration with ferric chloride : 0,0963 gave 18.5 C.C. moist nitrogen a t 20' and 750 mm. N = 21.68. C,H,03N, requires N= 21.21 per cent. Some of the materials used in this research were purchased by a grant from the Research Fund Committee of the Society, for which the authors desire to express their indebtedness. MUNICIPAL TECHNICAL SCHOOL, BLACKBURN.

ISSN:0368-1645    

DOI:10.1039/CT9028101563

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

THE CONSTITUENTS OF COMMERClAL CHRYSAROBIN. 1578 CLVK-The Constituents of Commercial Chrysarobin. By HOOPER ALBERT DICKINSON JOWETT and CHARLES ETTY POTTER. CHRYBAROBIN is a substance obtained from Araroba or Goa powder by extracting with certain solvents, for example, ch loroform, evaporating to dryness, and powdering. It was first examined in 1875 by Attfield (Phccrm. J. 1875, [iii], 5, 721), who found the chief constituent t o be chrysophanic acid, C15Hlo04, identical with that previously obtained from rhubarb by Schlossberger and Dopping (Annalen, 1844, 50, 213). I n 1878, Liebermann and Seidler (Ber., 11, 1603) showed that chrysarobin was not identical with chrysophanic acid, but contained a distinct substance, chrysarobin, C,,H,,O,, together with a varying amount of chrysophanic acid into which it was converted by oxidation The formula aesigned to chrysarobin was deduced from analyses of the1576 JOWETT AND POTTER: b recrystallised substance, which agreed fairly well with the formula proposed, but no determination of the molecular weight was made.A crystalline acetyl compound mas obtained which, however, on analysis gave numbers differing from thosa required for the formula C30H2207(C2H30)4 (Found C = 67.5 ; required C = 68.5 per cent.). The subject was not again referred‘ to for many years, and in the meantime the product has been sold indiscriminately as chrysarobin or chrysophanic acid. I n 1899, Hesse (Annalen, 309, 32) examined chrysarobin and obtained results differing from those recorded by previous investi- gators. H e showed that crude chrysarobin contained no chrysophanic acid, but was a mixture of two parts of chrysarobin, C15H1203, with one of its methyl ether.H e was, however, unable to obtain chrysarobin free from it; methyl ether, and arrived a t this conclusion from indirect evidence, Eight specimens, varying in melting point from 152Oto 1 7 4 O and purified by different means, were annlysed, but all yielded methyl iodide by Zeisel’s method, thus showing the presence of a methylated constituent. When the mixture was treated with hydrochloric or hydriodic acid, chrysophanohydroanthrone was obtained which was considered by Hesse to be isomeric with chrysarobin. On acetylation, however, the reverse change takes place, chrysophanohydronnthrone bsing converted into chrysarobin, since both yield the same triacetyl- chrysarobin.Chrysophanohydroanthrone and chrysarobin are both readily oxidised to chrysophanic acid, but if the impure chrysarobin is used a mixture of chrysophanic acid and its methyl ether results. Hesse thus regarded chrysarobin as the anthranole of chrysophanic acid. Before stating the results of the present investigation, we desire to point out that some of Hesse’s deductions are not in accordance with his observations, and further that simpler explanations than his can be given which are more in accordance with the facts. I n the first place, the analyses of the different specimens of chrysarobin do not agree with the assumption that they consist of a mixture of chrysarobin and its methyl ether. *If this were so, the percentages of carbon and hydrogen found should lie between those required for the two substances, whereas in all cases they are less than that required for either substance : C,,H120, requires C --- 75.0 ; H = 5.0 per cent.C1,H1,03*CH3 requires C = 75.6 ; H = 5.5 per cent. It therefore follows that the methylated constituent must contain Secondly, chrysarobin is assumed by Hesse to be isomeric and not Found C = 74.0 t o 75.0 ; H = 5.0 to 5-3 per cent. less than 75.0 per cent, of carbon.THE CONSTlTUENTS OF COMMERCIAL CHRYSAROBIN. 1577 identical with chrysophanohydroanthrone (obtained by Liebermann by the reduction of chrysophauic acid). Yet both behave similarly t o certain reagents and yield the same triacetylchrysarobin on complete acetylation.Their gacetyl compounds showed similar properties although of slightly different melting points, 238’ and 216’, but the latter contained some of the methylated constituent and was thus probably impure. Furthermore, by the action of hydrochloric acid on the mixture, chrysophanohydroanthrone was obtained, and Hesse assumed that in this reaction the antahranole was converted into the isomeric hydro- anthrone. I n order, however, to explain the formation of triacetyl- chrysarobin from chrysophanohydroanthrone, it is necessary to assume that the reverse change, that is, conversion of the hpdroanthrone to the anthranole takes place tinder the influence of acetic anhydride. These difficulties are removed by the simpler explanation that chrysophanohydroanthrone and chrysaro bin are identical, and are the anthranole of chrysophanic acid.It is almost certain that the acetyl derivative of chrysophanohydroanthrone (m. p. 230-231 ’), described by Liebermann (Bey., 1881, 21, 437), was triacetyl- chrysarobin, and had not the complex molecular composition assigned to it. Liebermann himself thought he had obtained this substance from.natura1 chrysarobin (Aiznalen, 1882, 212, 41). I n view of the incomplete state of our knowledge of chrysarobin, and especially of the methylated constituent, we have made a thorough investigation of the subject in order to elucidate these points. After a very tedious and difficult process of separation, we have i solated from commercial chrysarobin the following substances : Chrysarobin, C,,H,,O,, m.p. 204’. Dichrysarobin,* C3,H,,O7, no sharp melting point. Dichrysarobin methyl ether,* C,,H,,O,~CH,, m. p. 160’. A substance, C17H1404, m. p. 181’. Despite a very careful search, we have been unable t o isolate any other definite substance, although a varying amount of amorphous product was always obtained. Chrysarobin is shown t o be identical with Liebermann and Seidler’s chrysophanohydroanthrone, and since it yields chrysophanic acid on oxidation it must be regarded as the anthranole of this substance. Dichrysarobin corresponds to Liebermann and Seidler’s chrysaro bin, but occurs only in very small amount in commercial chrysarobin, * Although this substance does not correspond in composition with a polymeride of chrysarobin, we propose to retain for it the name “dichrysarobin ” given by Hesse t o a substance which he regarded a3 the polymeride, but which, as we show in this paper, had the composition now assigned to it,15’78 JOWETT AND POTTER: which consists mainly of chrysarobin and dichrysarobin methyl ether.Dichrysarobin is very different ‘in its physical properties from chrysarobin, but as it yields the same oxidation and reduction products it must be closely allied to it. We therefore suggest for it the f ollowing constitutional formula, which differs but slightly from that first proposed by Liebermann and Seidler for chrysarobin. I 0 I This formula best explains the reactions of the substance and its relationship to chrysophanic acid and chrysarobin, but further experi- ments are needed to establish it definitely.The action of acetic anhydride and of hydriodic acid on these substances has been studied, and the opportunity taken to prepare pure chrysophanic acid and its acetyl derivative. Several melting points have previously been given for this acid, and Hesse has shown that the acid &s previously described is mixed with a varying quantity of a methylated constituent, which has not been isolated, but was supposed to be the methyl ether of chrysophanic acid. The constants previously given have therefore been those for impure substances. Preliminary experiments on this point indicate that the methylated constituent is not the methyl ether of chrysophanic acid but that of dichrysarobin. I n the cases both of crude chrysophanic acid and of chrysarobin, it was found easier to separate the acetyl compound than the original substance.Both chrysarobin and dichrysarobin yield P-methylanthracene on distillation with zinc dust. EXPERIMENTAL. This was prepared directly from the commercial chrysarobin by first extracting it with light petroleum, distilling the extract, and recrys- tallising the residue repeatedly from a large volume of hot ethyl acetate, By this means, after a very tedious fractional recrystallisa- tion, it was obtained in beautiful, lemon-yellow scales melting at 202O (cow.), and further recrystallisation from different solvents did not alter the melting point. It was insoluble in aqueous sodium carbonate, but dissolved in caustic alkalis, forming a yellow solution which, however, rapidly absorbed oxygen from the air and became red.It gave a yellow colour with strong sulphuric acid, and its alcoholic salu-THE CONSTITUENTS OF COMMERCIAL CHRYSAROBIN. 1579 tion became brown on the addition of ferric chloride. It was sparingly soluble in cold benzene, acetone, alcohol, glacial acetic acid, ethyl acetate, or light petroleum, but fairly soluble in these solvents when hot. When treated with hydriodic acid, no methyl iodide was formed. On analysis : 0.1156 gave 0.316 CO, and 0.0524 H,O. C=74*6; H=5*0. C1,Hl,O, requires C = 75.0 ; H = 5.0 per cent. When boiled with twice its weight of acetic anhydride for four hours, a product was obtained which melted a t 191-192', but by fractional crystallisation from glacial acetic acid was separated into two substances melting at 193' and 236-237' respectively, The substance melting a t 193' furnished, on analysis, the following result : 0.0482 gave 0.124 CO, and 0.022 H,O.C = 70.1 ; H = 5.0. C1,H1605 requires C = 70.4 ; H = 4.9 per cent. It was therefore diacetylchrysarobin, C15H~o03(C2H30)2, and the other substance was the triacetyl compound. When acetylated with acetic anhydride and sodium acetate, it yielded a triacetyl compound, C15H,0,(C,H,0),, crystallising from glacial acetic acid in hard, yellow cubes melting at 238'. This was insoluble i n water and very sparingly soluble in cold or hot alcohol, but fairly soluble in hot glacial acetic acid. The alcoholic solution had a bluish fluorescence. 0.1254 gave 0.317 CO, and 0.0566 H,O. Chrysarobin (or the chrysophanohydroanthrone of Hesse) was also easily prepared directly from the crude petroleum extract of commercial chrysarobin in the following manner.The residue, after removal of the petroleumby distillation, was heated with four to five times its weight of hydriodic acid of sp. gr. 1.7 for two hours a t 130-140' and the mixture then poured into a large volume of water. The precipitate was dried and extracted with hot benzene in a Soxhlet apparatus, the benzene solution distilled, and the residue crystallised from hot ethyl acetate until of melting point 204'. 0.1934 gave 0.5306 CO, and 0.0864 H,O. 0.394 raised the b. p. of 19.1 benzene 0.21'. On analysis : C= 68.9 ; H=5*0. C,,H1,06 requires C = 68.9 ; H = 4.9 per cent. On analysis : C = 74.8 ; H= 5.0. Mol. wt. = 262. Cl5HI20, requires C = 75.0 ; H = 5.0 per cent.Mol. wt. = 240. On acetylation with acetic anhydride or with sodium acetate and acetic anhydride, the same results were obtained as just described in connection with pure chrysarobin,1580 JOWETT AND POTTER: Chrysarobin, heated with an excess of hydriodic acid of sp. gr. 1.9 for one hour a t 1 Z O O was recovered unchanged, as proved- by the melt- ing point 203--204°, and the analysis of the resulting product : 0.1268 gave 0,349 CO, and 0.06 H,O C1,H,,O, requires C = 75.0 ; H= 5.0 per cent. These experiments prove that the chrysarobin originally present in commercial chrysarobin and the chrysophanohydroanthrone obtained from it by the action of hydriodic acid are not isomeric, as stated by Hesse, but identical. When chrysarobin was oxidised in alkaline solution, chrysophanic acid was formed, as stated by Liebermann and Seidler and confirmed by Hesse.When distilled with zinc dust, a yellowish sublimate mas obtained which, after recrystallisation from alcohol; formed yellowish plates melting a t 199-2009 C = 75.0 ; H = 5.2. On analysis : 0.0592 gave 0.2038 CO, and 0.0332 H,O. This substance was therefore a methylanthracene, probably the /3-modification. From these reactions and the fact that chrysarobin yields a triacetyl compound, it is clear that it must be regarded as the,anthranole of chrysophanic acid, The anthranole formula for chrysarobin as pro- posed by Hesse is thus confirmed. C = 93.9 ; H = 6.3. C,,H,, requires C = 93.7 ; H = 6.3 per cent. Bichrysarobin, C,,H,,O,. This substance is readily obtained from the crude petroleum extract of commercial chrysarobin as follows : the extract is heated with four or five times its weight of hydriodic acid of sp.gr. 1.7 for two hours at 130--140° in a reflux apparatus, and the mixture poured into water and filtered. The precipitate is washed wiih water, and then dried and extracted with hot benzene in a Soxhlet apparatus to remove the chrysarobin. The residue insoluble in benzene is recrystallised from hot ethyl acetate or glacial acetic acid several times. It is thus obtained in beauti- ful, orange tabular crystals, which decompose at about 250' but have no sharp melting point. It is soluble in ethyl acetate or glacial acetic acid, but insoluble in benzene (distinction from chryearobin), and appears to be more readily oxidised in alkaline solution than chrys- arobin.As the purity of the crystals could not be determined by the melting point, three different specimens crystallised from various solvents were apslysed : It gives a yellow colour with sulphuric acid.THE CONSTITUENTS OF COMMERCIAL CHRYSAROBIN. 1581 I. 11. 111. 0.1366 gave 0.363 CO, and 0.0594 H,O. C = 72.6 ; H=4.8. 0,1356 ,, 0.3592 CO, ,, 0*0600 H,O. C=72.2; H=4.8. 0.1194 ,, 0.316 CO, ,, 0.0520 H,O. C=72.2; H=4.9. C,,H,,O, requires C = 72.6 ; H = 4.8 per cent. Owing to the sparing solubility of this substance in solvents, the molecular weight could not be determined. By using the acetyl com- pound of methyldichrysarobin, however, this' constant was determined and the above formula thus confirmed.The acetyl compound, C,,Hl,07(C,H,0)6, was prepared by boiling dichrysarobin with considerable excess of acetic anhydride for three to four hours, cooling, and then adding alcohol. The acetyl compound separated in yellow cubes, which were recrystallised from acetic acid and alcohol, and thus obtained of constant melting point 179-181'. On analysis : 0.1044 gave 0,2568 CO, and 0.0456 H,O. Acetylation with acetic anhydride and sodium acetate yielded a pro- duct which could not be crystallised. Hexa-acetyldichrysarobin differs from the acetyl derivatives of chrysarobin in being much more soluble in organic solvents, such as alcohol, and in not giving fluorescent solutions. Further treatment with hydriodic acid had no action on dichrys- arobin, as after heating with the acid a t 130' in a sealed tube the substance was recovered unchanged.By oxidation with air in alkaline solution, chrysophanic acid was obtained, identified by its melting point, 1 go', and its characteristic colour reaction with sulphuric acid. Although the oxidation pro- ceeded more rapidly, than in the case of chrysarobin, the yield of chrysophanic acid was less. By distillation with zinc dust, a yellowish sublimate was obtained which, when recrystallised f porn hot alcohol, formed yellowish needles melting a t 1 9Y-2OO0, and on analysis proved to be a methylanthracene, probably the /3-modification : C = 67-1 ; H = 4.8. C,2H,6013 requires C = 67.4 ; H = 4.8 per cent. 0.0974 gave 0.3335 CO, and 0.0536 H20. C- 93.3 ; H = 6.1. C,,H1, requires C = 93-7 ; H= 6.3 per cent.The insoluble residue, left after extraction of commercial chrys- arobin with light petroleum, was crystallised from ethyl acetate and a substance separated which seemed to be identical with dichrysarobin, but was apparently less soluble in ethyl acetate or glacial acetic acid. After repeated recrystallisation from these solvents, it was obtained in crystals having no sharp melting point, but decomposing at about 250'. On analysis :1582 JOWETT AND POTTER: 0,084 gave 0.2222 CO, and 0.0366 H,O. The acetyl derivative was prepared in the usual way and analysed 0.0402 gave 0.098 CO, and 0-0184 H,O. C = 72.2 ; H= 4.8. C,,H,,07 requires C = 72.6 ; H = 4-8 per cent, with the following result : C = 66.5 ; H = 5.0. 4 C,,H,,07 requires C = 67.4 ; H = 4.8 per cent.Dichrysarobin Methyl Ether, C3,H2,0p An examination of the petroleum extract of commercial chrysarobin indicated the presence of a methylated substance in addition to chrys- arobin. The formation of chrysarobin and dichrysarobin by the action of hydriodic acid on the extract and their stability towards this reagent, rendered it highly probable that the methyl ether of di- chrysarobin was present in ' commercial chrysarobin. The mother liquors, from which chrysarobin had been separated, were therefore worked up, and after a tedious process of Fractional crystallisation a product was obtained melting constantly at 160', which was slightly more soluble in ethyl acetate than chrysarobin but similar in other respects, On analysis : 0.2044 gave 0.5474 GO, and 0.0904 H20.0.185, by Zeisel's method, gave 0.0604 AgI. The residue, after treatment with hydriodic acid; had the properties of dichrysarobin. The acetyl compound, C3,H2,07(C,H,0),, was prepared by acetylating the mixture of chrysarobin and the methylated substance in the usual way and extracting it with hot alcohol. The portion insoluble in the solvent was triacetylchrysarobin, the soluble portion was precipitated from the alcoholic solution in three fractions with water. It was very soluble in alcohol, ethyl acetate, snd glacial acetic acid, and could not be obtained crystalline. On analysis : C = 73.0 ; H= 4.9. C,,H,,07 requires C = 73.0 ; H = 5 01 ; CH, = 2.9 per cent. CH3= 2.1. The middle fraction melted a t 135'. 0.123 gave 0.305 CO, and 0.0578 H20.0.206, by Zeisel's method, gave 0.0776 AgI. CH, = 3.4 per cent. 0.721 raised the b. p. of 14.2 alcohol 0*085", Mol. wt. = 687. C,,H,,O,, requires C = 68.3; H = 5.0; CH, = 2.1 per cent. Mol. wt. = 720. It is extremely probable that this acetyl derivative is identical with, or is largely contained in, a substance examined by Hesse and regarded by him as hexacetyldichrysarobin, as i t agreed with it in physical pro- perties and chemical composition. Hesse found that his substance C = 67.6 ; H = 5 - 2 . 0.0684 ,, 0.169 CO, ,, 0*035!6 H,O. C = 67.4 ; H = 5.3.THE CONSTITUENTS OF COMMERCIAL CHRYSARORIN. 1583 melted at 125O and gave the following data: C=68*0; H=5*0 per cent. Mol. wt.=692. Hesse supposed that his substance was produced by the polymerisation of chrysarobin by the prolonged action of the acetylating agent.This, however, we find not t o be the case, as tho mixture of chrysarobin and dichrysarobin methyl ether, when treated with acetic anhydride and sodium acetate for half-an-hour, gave approximately equal quanti- ties of triacetylchrysarobin and penta-acetyldichrysarobin methyl ether, whilst pure chrysarobin under exactly similar conditions gave a quantitative yield of triacetyIchrysarobin. The polymeride, therefore, must pre-exist in the mixture. That it was a methyl ether was proved by treating the mixture with hydriodic acid and examining the alkyl iodide formed; it distilled completely below 50' and was therefore methyl iodide. Substance, CI7H,,O,. M. p . 181'. In the process oE working up the residual crude chrysarobin left after extraction with light petroleum, a small amount of a beautiful, crystalline substance melting constantly at 181' was obtained.It had the general properties of the substances associated with it in crude chrysarobin. On analysis : 0.108 gave 0.285 GO, and 0.052 H,O, 0.19, by Zeisel's method, gave 0.141 Agl. C1,7H,,0, requires C = 72.3 ; H = 5.0 ; CH, 5= 5.3 per cent. The analytical data agree very well with this formula, and the large amount of methyl iodide formed on treatment with hydriodic acid precludes the possibility of it being a mixture of the other constituents previously mentioned. The acetyl compound, prepared in the usual way,!was crystallised from alcohol and formed orange-red crystals melting at 2 15-2 16O. The solution was not fluorescent. 0.0938 gave 0.2276 CO, and 0.042 H20.C = 66.2 ; H = 5.0 per cent. These figures unfortunately do not agree well with any likely formula, and we are unable a t this stage of the inquiry t o offer any suggestions as to the constitution of this substance. C = 72.0 ; I€= 5.3. CH,=4*7. On analysis : Chrysophanic Acid, C,, H,,O,. For the sake of comparison, a preliminary examination was made of some chrysophanic acid prepared from rhubarb. This was obtained as a brown, indistinctly crystalline powder melting at 160'. On analysis :1584 THE CONSTITUENTS OF COMMERCIAL CHRYSAROBIN. 0.1544 gave 0,398 CO, and 0.059 H20. 0.1906, by Zeisel's method, gave 0.0452 AgI. The crude product obtained after treatment with hydriodic acid charred on heating, but had no sharp melting point, By recrystal- lisation it was separated into chrysarobin, melting a t 203O, and a substance which charred and had no sharp melting point.On analysis, the latter gave figures agreeing with those required for dichrysarobin : C,,H2,07 requires C = 72.6 ; H = 4.9 per cent. C = 70.3 ; H= 4.2. CH,= 1.5. C,,H,,O, requires C = 70.9 ; H = 3.9 per cent. 0.1668 gave 0.446 CO, and 0.0746 H20. The acetyl compound of chrysophanic acid, prepared in the usual On C=72.7 ; H=5*0. way and recrystailised from glacial acetic acid, melted at 203'. analysis : 0.1914 gave 0.4722 CO, and 0.0736 H20. C19Hl,0, requires C = 67.4 ; H = 4.1 per cent. Here, as in the case of crude chrysarobin, the acetyl derivative may be more readily separated from the methylated constituent than the parent substance. In order t o determine the physical constants of pure chrysophanic acid, about which there has been hitherto much uncertainty, pure chrysarobin, after treatment with hydriodic acid, was cocverted by aerial oxidation in alkaline solution into chrysophanic acid and thie recrystallised from several solvents until the melting point was constant.The pure substance melted at 190°. On analysis : C= 67.3 ; H = 4.3. 0.0984 gave 0.256 CO, and 0.0354 H,O. C,,H,,O, requires C = 70.9 ; H = 3.9 per cent. The acetyl derivative, after several recrystallisations, melted con- stantly a t 206' instead of 202--204O, as previously recorded. Attempts to prepare the methyl ether of chrysophanic acid were unsuccessful; even when heated in a sealed tube with methyl iodide and methyl alcohol a t loo', the original substance was recovered unchanged. Finally, in order to prove beyond question that chrysarobin was identical with chrysophanohydroanthrone, chrysophanic acid was treated with hydriodic acid, and the product proved to be chrysarobin by its melting point, 204O, and that of its acetyl derivative, 234-235'. Liebermann and Seidler's chrysophanohydroant hrone is therefore not the hydroanthrone, but the anthranole of chrysophanic acid. Further, the methylated compound accompanying chrgsophanic acid in rhubarb is not its methyl ether, as stated by Hesse, but is in all probability the methyl ether of dichrysarobin. Chrysarobin and dichrysarobin are readily oxidised by alkaline C= 70.9 ; H= 4.0.THE CONSTITUENTS OF AN ESSENTIAL OIL OF RUE. 1585 permanganate, but no product other than oxalic acid could be isolated from the result of the reaction. Fusion with caustic potash also yielded a negative result. Jt was thought of interest to examine a coiiimercial sample designated “absolutely chemically pure chrysarobin. ” This was found to have practically the same composition as that previously examined. After recrystallisation from ethyl acetate, it melted at 165-175O. On analysis : 0.103 gave 0.275 CO, and 0.0458 H,O. 0,333, by Zeisel’s method, gave 0.1166 AgI. CH, = 2.2. C,,H,,O, requires C = 75.0 ; H = 5.0 per cent. After treatment with hydriodic acid, it yielded a mixture of chrysarobin and dichrysarobin and WCLS thus in al! respects similar to that previously examined. C = 72-8 ; H = 5.0. THE WELLCOME CHEMICAL RESEARCH LABORATORIES.

ISSN:0368-1645    

DOI:10.1039/CT9028101575

出版商:RSC    

年代:1902

数据来源: RSC