摘要:

112 LE BAS: RELATION BETWEEN VOLUMES OF ATOMS OF XI.-A Relation betzoeerL the Volumes of the Atoms o f certain Organic Compounds at the Melting Poirit and their Valencies. Intequretatioiz by Means o f the Ba rl o w - Pop e T h e 03- y. By GERVAISE LE BAS, B.Sc. IN October, 1905, the author discovered that the volumes of the atoms in certain members of the paraffin hydrocarbon series and their derivatives taken near their melting points and also in many solid compounds, both organic and inorganic, mere very nearly integral multiples of the volume of combined hydrogen. In many cases these integral multiples coincide with the fundamental valencies of the atoms in question. This result, independently of its intrinsically interesting character, is a t the present time especially significant in consequence of the ideas put forth by Barlow and Pope in their recent important paper on the correlation of molecular structure and crystal- line form (Trans., 1906,99,1675).By regarding crystalline structures as closely-packed assemblages built up from the spheres of influence of the constituent elements, these authors have arrived a t the conclusion that, the fundamental valency of an element is proportional within narrow limits to the volunies of the atomic spheres of influence, It follows from this that a particular inolecular complex may beCERTAIN ORGANIC COMPOUNDS AT THE MELTING POlNT. 113 regarded as one in which the component atoms appropriate to them- selves portions of space proportional in volume to their valency, but, as, indeed, Earlow and Pope point out, the absolute volume, as the atomic sphere of influence of an element, is liable to differ from compound t o compound.It would seem, however, to follow, if no other determining factors than those promised by Barlow and Pope are operative, that the indicated relationship butween the valency and the volume of the atomic sphere of influence should be traceable throughout a whole series of homologous substances such as the normal paraffins. No obvious reason exists why the atomic sphere of influence of carbon or hydrogen should change appreciably in pasing from one member to another of such a series, especially if the terms chosen lie SO high in the series as to have nearly the same percentage composition. This aspect of the new theory finds support from an examination of molecular volumes, taken under the specified conditions. Tho data are derived from papers published by Krdff t on the normal paraEns (Ber., 1882, 15, 1716) and on the alcohols (Bey., 1883, 16, 1714).The values quoted in the following table are for liquid hydro- carbons at the melting point ; these temperatures are, as shown in the fifth column of the table, approximately equal fractions of the boiling points on the absolute scale, and hence may be considered ~ L S approximately equal fractions of the critical temperatures. The molecular volumes may thus be regarded as determined under corresponding conditions, that is, under conditions such that the repulsive forces in all cases have just overcome the attractive forces which hold them in their places in the crystalline structure.Xcctuvated Normal Hydrocarbons, CnKZql. + 2. Mol. Vol. Diff. Ty x S= Calc. FV. Undecane, C1,H, ......... 68 Dodecane, C,,H,6 ......... 74 Tetradecane, C,4H30 ...... 86 Pentadecane, C16H32 ...... 92 Octadecane, C,,H,, ...... 110 Tridecanc, C,,H,, ......... 80 Hexadecane, C,&[,, ...... 98 Heptadecane, Cl'lH36, ... 104 Nonadecane, C1,H4, ...... 116 Eicosane, C,,H,,. ........... 122 Heneicosane, CZiH44 ...... 128 Docosane, C,H,, ........ 134 Tricosane, C23H48 ......... 140 Tetracosane, C24H50 ...... 146 Heytacosane, C,H, ...... 164 Hentriacontane, C31Hs4.. . 188 Dotriacontane, C,,H,, , . , 194 Pentatriacontane, C,,H7,. 212 Mean values ........ VOL. XCI. = v. 201 '4 219.9 237'3 255.4 273'2 291'2 309-0 326.9 344'7 362.5 380.3 398.3 416'2 434.1 487'4 558.4 576'2 629.5 ....for CH,, 18-5 17.4 18.1 17.8 18.0 17.8 17.9 17.8 17.8 17'8 18'0 17.9 17.9 53 *3 71 *O 17'8 53.3 17.83 M. p,/B. p. 0.527 0.536 0'524 0530 0.520 0.519 0'513 0.512 0'506 Y/ w. 2'962 2.971 2.966 2,970 2.970 2.971 2'971 2.972 2.971 2.971 2-971 2.972 2.971 2.973 2.972 2.970 2.970 2'969 2.970 mol. vol. 201 -96 219.78 237 -60 255.42 273.24 291.06 308.88 326-70 344.52 362'34 380.18 398-00 415-80 433.62 487.08 558.36 576.18 629.64 II14 RELhTlON BETWEEN VOLUMES OF A4rI'OMS -4ND THEIll V>iLEX;CIES I n the table, TV is the valency number and the quotient W is the molecular volume divided by the valency number, thus representing the volume appropriated by one unit of valency in the respective hydro- carbon.The mean value of the latter, namely, S=2.970, is con- veniently described as the unit stere. It is apparent at once, from the constancy of the individual values OF 8, that the concept above referred to, and which is of fundamental importance in Barlom and Pope's theory, can be extended to the statement that in the series of normal paraffins regarded under corresponding conditions specified the spheres of atomic influence of carbon and hydrogen preserve almost the same relative magnitudes throughout the series. The extent to which this conclusion is true is measured by the closeness of the correspondence between the obaer ved molecular volumes (column 3) and the values, calculated as the products of the valency volume and the mean value of the unit stere, in the last column.The table shows that the mean increment of the molecular volume for the homologous increment CH, is 17.S3, a value which, when divided by the valency volume W=6, for methylene gives 2,972 for the value of the unit stere, a number almost identical with the mean value of S obtained from column 6. A more direct way of calculating the value of the unit or univalent stere for hydrogen is by means of equations of the following kind : 2X= 2P of C,,H2, - Vof C,,H,, ~ 5 . 7 . 25' = (V of C,,H,, + Vof C16H3J - V of C,,H,, = 6. S s 2.85. X = 3. The average value of X obtained in this way confirms that previously The volume of carbon is also found directly as follows : The conclusion is thus deduced that the molecular volume Y(at the melting point) of a normal solid paraffin of the molecular composition C1LH211+2 is given by the formula V = ( 6 1 ~ + 2 ) s = 6nX + 2X, where X= 2.970. Considerations similar to the above may be applied to homologous series of derivatives of the normal paraffins, as, for instance, the primary alcohols. The following table gives the observed molecular volumes of several of these compounds examined by Krafft (Zoc.cit.). found, namely, 2.970. Vof C = 17.83 - 5.94 = 11.89 = 4 x 2,972 = 427.OP'l'ICAL IYFLUENCE OF CONTIGUITY O F UNSATURATED GHOU 1's. 115 Nornzal AZcohoZs, C,,H,,,*OH. ?V. v. Yf w. 1 V X s. Noiiylcarhinol, C,,H2;0H ............... 64 189.3 2.943 190.08 Undecglcarbinol, C,,H,,'OH ............ 76 223.9 2.946 225.72 Tridecylcarl,iiiol, C,,H,,'OH ............ 88 259.8 2.953 261 '36 Pzntadecylcarbinol, C,,H,'OH ......... 100 296.0 2.960 297.00 Hcptadecylcarbinol, C,,H,:.'OH ......... 112 332.3 2970 332.64 As against the slight divergence of T/TVfrom the normal on the part of some of these alcohols, it has been found by a study of the ketones and fatty acids, in which latter series the hydroxyl group appears, that a satisfactory constancy is maintained. Thus, under the stated conditions, the molecular volumes of the primary alcohols C,,H,,+lOH derived from the normal paraffins are expressed by the equation V = (6% + 4 ) s = 6988 + 48. In a subsequent paper, the method of interpretation here described mill be applied to other homologous series and also to unsaturated substances. It is also the intention of the author to show that the regularities observed by Schroder in his study of solid compounds have underlying them relations similar to those given in this paper. So far as the carbon compounds are concerned,it may be stated that Schroder's value for the stere is 5.95, or double the value which is here assigned to S, the unit stere. MUXICIPAL SCHOOL OF TECHNOLOGY, MAKCIIESTER.

ISSN:0368-1645    

DOI:10.1039/CT9079100112

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

OP‘l’ICAL IYFLUENCE OF CONTIGUITY O F UNSATURATED GHOU 1’s. 115 X II.-The @pticul In$?i,ence of Co.iztiguity of Unsaturated Gmmps. By JULIUS WILHELM BRUHL. THE following remarks have reference to the striking physical pro- perties of certain terpenes and their derivatives to which attention has been called recently by Kay and W. H. Perkin, jun. (Trans., 1906, 89,839) and are made with the object of correlating their results with those already obtained by myself and other inquirers. The determinations of magnetic rotatory power made by Sir W. €3. Perkin shorn that d-limonene (and inactive dipentene) differs in an altogether remarkable manner from A”5(Y)-p-menthadiene, the valuo abtained for the latter being “ abnormally ” high, The difference is I 2116 BRUHL: THE OPTICAL INFLUENCE OF ascribed by Kay and Perkin to the presence in the p-menthadiene of two contiguous ethenoid linkings.Now it can be shown not only that this explanation is a correct one, but also that it could have been foreseen with csrtainty that hydrocarbons so constituted would exhibit properties such as they are found to possess. It is a well known fact that magnetic rotatory power and refractive and dispersive power are correlative properties ; relations which de- monstrably hold good between structure and refractive or dispersive power must, therefore, also obtain between structure and magnetic rotatory power. During the past sixteen years, indeed, I have shown by numerous researches,+ carried out with a large body of material, that contiguous unsaturated groups, not only *C:C*C:C* but also -C:C*C:O, &c., always give rise to a striking increase of molecular refractive and still more of molecular dispersive power. I have often pointed out that the phenomenon is general, being observed not only in acyclic but also in the benzene, hydrobenzene and other series; moreover, that its existence affords a means, particularly in the case of terpenes and oxyterpenes (camphors), of determining whether or no contiguous unsaturated groups are present in a compound.Many Continental investigators have confirmed my conclusions, especially Eykman (J. F. Eykman, Ber., 1889, 22, 2736; 1890, 23, 855; 1892, 25, 3069), some of whose results are included in the following table, comprising a number of simple examples illustrative of the property under discussion : CH,:CHTH,*CH;CH:CH, , .. ,) 28-90 ,, 29-57 ,) 0.67 Diallyl, b. p. 61". Theory for C,H,, ......... ), 28'89 CH*CH:C H i CH,.. ..................... ll I CH*CH:CH Tropilidene. HC CH HC<L>*CH, .................. ,, 30'79 ), 31.63 ,, 0.84 HC CH Toluene. Theory for C,H8 ......... ,, 30.89 - ~ * My first observations on this subject are to be found in Zeit. physiknl. Chcm., 1891, 7, 140 ; my later work has been published partly in that periodical and also in the J. pr. Chem. and in the Berichte.CONTIGUITY HC CH CH,’ o*c/(~\c =/ *CH:CH-CH, HC CH Anethole. HC CH Methylchavicole. Theory for CloHl,O’ ..... CH,:CH*CHO ................... Theory for C,H,O” I=1 ......... Acrolein. HC C-OH HC=CH HC~\)C.CHO ............... Salicylaldehyde.Theory for C,H,O’O’ ...... OF UNSATURATED GROUPS. HC OH EIC~%*CH:CH-CH:CH*CO,H \=/ ,) HC CH Cinnamylideneacetic acid, dis- solved in acetone. Theory for C,lH,,O’O‘’ iZ5 .... 9 9 45.95 ,, 45.89 16-01 15.67 34.03 32.52 60 ‘42 50.06 117 2.95 2 ‘04 1 *75 0.73 0.58 2 -68 1 ‘28 9.70 2.04 These few examples, which could easily be multiplied ten-fold, show that in every case the compound in which the unsaturated groups are contiguous has the greater molecular refractive and dispersive power, the experimental values in such cases always exceeding those calculated in the conventional manner ; the differences, however, are not at all equal; they vary according to the character and number of un- saturated groups, being greatest and enormously in excess in the case of cinnamylideneacetic acid, in which there are several contiguous unsaturated groups.It is remarkable that the benzene nucleus of toluene, which is a system of contiguous ethenoid linkings, does not behave optically as though it were thus constituted, the values it affords being normal, not in excess of those calculated (see table). Benzene and its homologues all behave alike ; so do also benzene derivatives obtained by substitut- ing univalent atoms for hydrogen : for example, bromobenzene, &c. What may be the cause of these seeming exceptions? In benzenoid compounds, the closed ring consists of six equal carbon atoms forming three equally situated ethenoid groups which apparently neutralise one another. On this account, such compounds cannot118 BMUHL: THE OPTICAL INFLUENCE OF exbibit the properties, chemical or physical, of ordinary contiguous (conjugated) ethenoid systems.As soon, however, as the equality of the six-carbon atoms is destroyed, the balance is disturbed; the pro- perties characteristic of contiguous ethenoid linkings then a t once make their appearance. The disturbance of balance may be effected in various ways. One method is to insert another atom or radicle between two of the six carbon atoms of the benzene nucleus, as in the case of tropilidene, which is formed by insertion of CH, into the benzene ring (see table). A secocd method of destroying the equality of the carbon atoms in the benzene ring consists in associating one or more of these atoms with an unsaturated group, such as C:C, C:O, NO,, NH,, &c.These groups apparently exercise a special attractive influence on the nucleus and by conferring stability on the carbon atom with which they are com- bined disturb the balance within the ring. I t is easy to show that such special attractive influences are actually a t work. Thus allyl- benzene, Ph*CH,*CH:CH,, and all its derivatives are labile compounds which are easily convertible into propenylbenzene or cinnnmene, Ph*CH:CH*CH,, and its derivatives; the latter are stable and not reconvertible into their isomerides. Owing to the special attractive influence exercised by the ethenoid group 0:C of the lateral chain upon the carbon atom of the benzene ring t o which the group is attached, the carbon atom in the benzene ring acquires a particular quality and properties are developed which are characteristic of com- pounds containing contiguous ethenoid linkings ; in fact, every known cinnamyl derivative (a large number have been examined) has a remat kably high refractive and dispersive power in comparison with that of the isomeric allylbenzene derivatives, none of which gives an abnormal value.Anethole, C6H4( OCH,)*CH: C EX* CH,, and methyl- chavicole, C,H,(OCH,)*CH;CH:CHa, are good instances (see table) of such differences. It is to be supposed that two or more C:C liukings are attached to a benzene nucleus in naphthalene, phenanthrene and other condensed benzenoid hydrocarbons ; these certainly are the cause of the excep- tionally high refractive and disper5ive power known to be characteristic of such hydrocarbons.The aldehydes, acids and ethereal salts in which a carbonyl group C:O is attached to a benzene ring show a similar behaviour; for example, salicylaldehyde (see table), amino- and nitro-benzene and their derivatives. In the case of phthalic compounds, in which two CO groups are attached to the benzene nucleus, the increased optical effect is likewise rernwknhle. I: have ~ I F O drawn attention to theCON T I C; U IT I‘ 0 F UN S A‘I’U It A TE D G; R OUPX . 119 increased optical effect manifest in derivatives of anthrnnilic acid, C,H,<c$oH):o, h H, in a special investigation (Ber., 1903, 36, 3640). A third method of destroying the equality in benzene consists in either removing one of the ethenoid linkings from the ring into the side chain or in dispensing with it altogether; by the former process ; toluene, for example, would be changed into a compound having an increased optical effect, /==\-CH, (I); whilst if the latter process were applied to benzene, one of the isomeric hydrobenzenes, ’ (11) or /-\ (HI,), the prototypes of the terpenes, mould be formed ; of these, I1 would exercise a ‘‘ normal ” and 111 an increased optical effect.I have examined I1 niysclf (J. p ~ . Clhem., 1894, 40, 248); I11 is unknown, Aiiwers (Bey., 1906, 39, 3748) has recently referred to the fact that not only compounds of types I and I11 but \==/- /=\ \=/ \=/ /-\ also those of the fourth type, ’’ \-C:C (IV) all exhibit a remark- \-/ ~~ ably increased refractive and dispersive power ; he, however, expressly recognises that it was to be expected from iny researches that com- pounds of these three types would be supra-refractive and supra- dispersive; 11 had indeed confidently expressed the opinion to hiin before hs had carried out any of his determinations that such would turn out to be the case.The discovery made by Sir W. H. Perkin that the A3s(g)-p-men- thadienes (type IV) are more refractive and dispersive than limonene, in which there are no contiguous ethenoid linkings, serves to confirm the views which I have set forth in these pages. And considering the general correlation which exists bet ween refractive and dispersive power and magnetic rotatory power, it was to be foreseen that limonene would exhibit normal and the A3 S‘”-p-menthadienes an increased magnetic rotatory power, although the extent of the difference could not have been predicted. There is one other point OF interest on which I may be allowed to add some remarks. Sir W.H. Perkin has found that the magnetic rotatory power is slightly higher (13.061) in the case of optically active d-A3ns(9’-p-men- thadiene than in that of the inactive dl-compound (12*939).* The values found for d- and I-limonene and dipentene were much lower, namely, 11.246, 11.162 and 11.315. * In the coinparisons iiiacie by Kay and Pcrkin (1). 554), tlie sninc value is erroneously giveii to both co~iipoui~ds.120 BROHL: THE OPTICAL INFLUENCE OF Comparing the optical properties generally of the various isomerides, it will be observed, on reference to Kay and Perkin's paper, that the values all follow the same order but that the differences between the refractive and dispersive powers, especially the latter, of d- and dl-A3.scg)-p-methadiene are remarkably high in comparison with those between the magnetic rotatory powers.These differences are probably real, as they exceed the ordinary experimental errors. Unfortunately the refractive and dispersive constants of d- and I-limonene were not measured by Sir W. H. Perkin. But judging from former determinations, there is no reason to suppose that appre- ciable differences exist in either refractive or dispersive power between d- and Elimonene and inactive dipentene. The last substance can be obtained by simply mixing d- with I-limonene and is probably merely an inactive mixture of optical antipodes. What then can be the reason that d-A3.*cg)-menthadiene and the dl- variety differ to such an extent in molecular refractive and still more in molecular dispersive power, whilst limonene and dipentene do not ? I think that it is not improbable that dZ-A3*s(g)-p-menthadiene is not a mere inactive mixture but a racemic compound of the d- and I-antipodes.It is probable from Kay and Perkin's observations that dLA1-tetrahydro-p-toluic acid is not an inactive mixture but a racemic compound of the d - and I-components; it may well be that the hydro- carbon prepared from it by simple chemical transformations i a also racemic." Of course, a conclusion of such consequence requires to be con- firmed by further experiments, which, however, thanks to the progress in synthesis due to the researches of W.H. Perkin, j u a , and his collaborators, will not offer great difficulties. ADDENDUM. I n the above paper I mentioned that it was desirable to re- determine the spectrochemical constants of d- and I-limonene and of the inactive mixture of them (dipentene). By the kindness of Messrs. Schimmel and Go., I am now enabled to give these constants. This firm sent me d- and I-limonene which had been specially prepared for me with great care. d-Limonene was obtained from cumin oil (Cccrum car&), I-limonene from the oil of the cones of the silver fir {&&a pectiryata). Both, terpenes were fractionated until the rotation * It must, however, be mentioned that the dl-hydrocarbon was prepared by eliminating water from the corresponding alcohol by boiling it with potassiuni hydrogen snlphate.It seems possible that, by this means, a partial inversion of the terpene generated might have taken place and that the special properties of this dl-terpene are perhaps due to such an alteration. This can only be decided by new physical determinations with a sample not treated with potassium hydrogen sulphatc.CONTIGUITY OF UNSATURATED GROUPS. 121 remained constant. It mas, however, not possible to obtain the two limonenes of quite equal rotatory power, that of I-limonene remaining a little lower. It seems, according t o the opinion of Messra. Schimmel and Co., that E-limonene is :wcompanied by some other constituent not separable by fractional distillation. This view was confirmed by the fact that a mixture of equal weights of d-limonene (aD + 104'15') and E-limonene (a, - 1Ol03O'), which have the same specific gravities (di' = 0.8402 and u!:".~ = 0*8407), does not display a rotatory power equal to the difference .t 104.015' - 101'30'= + 2O45', but that the rotation was actually found to be + l029', tha mixture having again a practically unchanged specific gravity (di"85 = 0,8402).As there is no other method of purifying the limonenes except by fractional dis- tillation, the two samples prepared by Schimmel and co. were used directly for my purpose. I am obliged to my colleague Prof. A. Klages and Mr. E. Sommer for making the measurements. Four series of determinations were made : (1) on d-limonene, (2) on Llimonene, (3) on a mixture of equal weights of both, and (4) on a mixture obtained by adding to cl-limonene so much of the I-compound that the deviation in the polarimeter became inappreciable.TABLE. a19,5' = I. d-Lirnoneiie, b. p. (corr.) 175?&-176"/763 mm. ............... +104"15' 11. I-Limonene, b. p. (corr.) 175*5-176-5"/763 mm. ............... a:9'5"= - 101"SO' 175*6-176~5"/763 mm. .......................................... ,19"= $- l"29' inactive, b. 1). (cow.) 1$5'6-176~6"/763 rnin. .............. agoo= 0"OO' 111. Mixture of equal weights 01' d- and I-lirnonene, b. p. (corr.) I V. I-Liniouene added to d-liinonene uiitil the mixture bocitiiie n. . to. d;. Ha- D. H6. HY. I. 21'0" 0'8402 1.47124 1 '47428 1'48223 1.48886 11. 20.6 0.8407 1.47157 1.47468 1'48256 1'48924 111. 20.7 0'8409 1.17143 1.47448 1 '48239 1.48904 IV.20.86 0'8402 1*%7134 1'47443 1'48231 1 *4889 8 nz - 1 _ _ _ ~ (?iJ+ 2)d Ii". I. 0-3328 11. 0.3328 111. 0.3327 I V . 0.3329 D. IIg. 0.3347 0.3395 0.3347 0-3394 0 *3345 0.3393 0-3348 0.3395 H". I. 45'26 11. 45'26 111. 45'24 I V . 45.27 Theory for C,,H,, 44.97 VOL. XCI. ~ ~ ~~~ HY. 46.71 45'51 46'-t7 45'52 46-16 46'71 45'49 46'14 46-68 45'53 46'17 46.72 45'24 - 46'40 D. HP- HY. 0.3434 0.3434 0.3433 0'3435122 DIXON AHD HAWTHORN^ : On reference to the table, it is seen that the agreement between d- and I-limonene is so excellent that the amount of hetero- geneous constituents in I-limonene must be but very small. There is further a very close accordance between the theoretical values and those observed for the molecular refraction and an almost absolute agreement as regards molecular dispersion.My numbers are also in satisfactory harmony with the figures given by Sir W. H. Perkin for dipentene; mine are a little higher for moledular refraction, and somewhat lower for molecular dispersion, The main result of these determinations is the fact that d- and Glimonene and their inactive mixture (dipentene) display, except in rotatory power, almost absolutely equd constants in every respect : in boiling point, specific gravity, refractive indices for every wave-length, specific and molecular refractions and dispersions within the whole visible spectrum. Since d- and dl-h”8(g)-p-menthndiene, prepared by Kay and Perkin,’ show remarkable differences in these physical constants, it is obvious that their relation cannot be the same as that of d- and I-limonene on the one hand and dipentene on the other. Therefore dZ-A3~*(’)-p- menthadione is probbbly a racemic compound-if the properties are tiot altered during its preparation (boiling with potassium hydrogen sulphate). At present it seems more likely that the difference i n the optical behaviour of this cll-compound is due to racemisation and not to chemical change (conversion into terpenes of another kind), as the magnetic rotation of d- and dZ-A“~8(9)-p-menthadiene dis- plays but slight differences. A decisive conclusion, however, in this very interesting question can only be arrived a t by preparing the dl-compound avoiding treatment with potassium hydrogen sulphate and by redetermination of its physical properties. HEIDELBEEG,

ISSN:0368-1645    

DOI:10.1039/CT9079100115

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

122 DIXON AHD HAWTHORN^ : xIII.- The Action of Acid Chlorides on Thiozc?*ecxs. By AUGU~TUS EDWARD DIXON and JOHN HAWTHORNE. IT is well known t h a t alkylogens can unite with thiourea cnd with certain of i t s derivatives, in particular with those where univalent hydrocarbon radicles replacs one, two, or three hydrogen atoms of the nitrogenised groups in CS(NH,), or NH:C(SH)*NH,. Since, in the products, the alkyl, R, of the alkylogen, RX, is com- bined with the sulphur atom, the change, where a thiourea is concerned,THE ACTION OF ACID CHLORIDES ON THIOUREAS. 123 may most simply be explained by supposing the hydrogen of the group to be substituted by the alkyl group, thus : NH:C(NH,)*SH -+ RX =NH:C(NH2)*SR + HX. Being highly basic, the products retain the acid, KX, which is eliminated by alkali, leaving the free base or pseudothiourea isomeric with the ordinary thiourea containing the same radicle.Where union is effected between an alkylogen and a thiocarbamide, for example, PhNH*CS*NH( C,H,), a molecular change of the latter may be supposed to occur with formation of PhN:C(NH-C,H,)*SH (or its tautomeride), which then interacts as shown above. Probably an additive compound, such as C,H,-NH PhNH>C<zR, is first formed, and a hydrogen atom then withdrawn (as HX) from the NH group. If the sulphur atom is already couldned with a hydrocarbon group, the free base (but not its salts) can unite with the radicle of an alkylogen; in this case the radicle attaches itself to a nitrogen atom (see, for example, Bertram, Ber., 1892, 25, 48).Concerning the behaviour of acylogens with thioureas, our know- ledge is very limited. So long ago as 1875, Claus described (Ber., 1875, 8, 42) a molecular compound CH,N,S,C,H,OCI, obtained by acting on thiourea with acetyl chloride below 40"; the product is said to dissolve unchanged in cold alcohol, but to decompose when the solution is heated, without formation of acetylthiourea. Benzoyl chloride, on the other hand, acts on thiourea to produce benzoyl- thiourea, but only a t 120' (Pike, Be?.., 1873, 6, 755). If, however, acetyl or benzoyl chloride is slowly added t o a pyridine solution of thiocarbanilide, a monoacetgl or a dibenzoyl derivative is formed (Deninger, Ber., 1895, 28, 1332), in which, presumably, the acid group is directly attached to nitrogen.More recently it has been shown (Trans., 1903, 83, 565) that thiourea unites very readily with methyl or ethyl chlorocarbonate to form in each case an additive product, CSN,H,,RO*COCl, the hydro- chloride of a base, NH,*C(NH)*S*CO,R, and, moreover, that from monosubstituted thioureas similar compounds may be obtained ; in so far as these products contain the acyl or oxidised group united with 'the sulphur, they are strictly analogous t o the alkylogen derivatives already mentioned. Furthermore, it has been shown (Dixon, Trans. 1906, 89, 909) that a similar combination occurs when thiourea is brought into contact with phenyl chlorocarbonate, PhO*COCl, there being formed the hydrochloride of a base, NH,*C(NH)*S.C02Ph, isomeric with a non- basic carbophenoxythiourea, PhO*CO*NH* C(NH)*XH, described in the same paper.Certain differences are noticeable amongst these psmduderivatires ; K 2124 DIXON AND HAWTHORNE : for exaniple, when the radicle, R, of the group, CO*OR, united with the sulphur atom, is fatty, the product readily loses carbon dioxide, and the radicle thereupon attaches itself directly to sulphur, forming an alkylpseudobase, NH,*C(NH)*S*R, whereas if this radicle is aromatic a phenol results, thus : NH,*C(NH)*X*CO,Ph + H,O = PhOH + CO, + NH,.C(NH)*SH. I n no case, however, where a chlorocarbonate was united to thiourea or to a monosubstituted thiourea did the radicle CO-OR, or any part of it, become attached to nitrogen. The group CH,*CO is of course more highly electronegative than the group CH,*O*CO and its congeners ; nevertheless, in view of the above facts, a possible explanation of the phenomenon observed by Claus suggests itself, namely, that acetyl chloride may to some extent play the part of an alkylogen, its acetyl group becoming combined with the sulphur so as to yield the hydrochloride of a pseudo- or basic form : NH,*C(NH)*SH c Cl*CO*CH, = NH,*C(NH)*S*CO*CH,,HCl.To throw light on the subject and to investigate the power of com- bination between acplogens and thioureas in general, the present inquiry was commenced. This is still incomplete, but circumstances having now arisen which will preclude us from continuing it jointly, we have the honour to lay before the Society an account of the principal results so far attained. Acetyl Chlor.icle nnd l’hiowea.As Claus gives scarcely any description of his compound (Zoc. cit.) beyond the statement that it is highly unstable, being decomposed a t about 40°, yet dissolves unchanged in warm alcohol, it was necessary to re-examine the substance, When finely powdered thiourea was covered with acetyl chloride, union occurred, with evolution of heat and formation of a bulky, lustrous, deliquescent white powder, apparently crystalline ; this, how- ever, was always more or less impure, as on determiniug the chlorine and sulphur respectively, figures were obtained corresponding to mixtures of additive compound and thiourea, in which the former was present to the extent of from 94 to 96 per cent. The only analytical figure given by Claus (Zoc. cit.) is that for chlorine, namely, 22 1 per cent., whilst CSN,H,,C,H,OCl requires C1= 26-98 per cent.; from this it would appear probable that he w a ~ dealing with a mixture containing 4 per cent. of thiourea and 96 per cent. of additive compound. Attempts to combine thiourea, suspended in benzene, with acetyl chloride proved unsuccessful, but ultimately a pure product wasTEIE ACTION OF ACID CHLORIDES ON TEIIOUREAS. 125 obtained by adopting the following method. To a nearly saturated solution of thiourea in warm acetone, excess of acetyl chloride, diluted with the same solvent, was added gradually ; the precipitate, consist- ing of minute, soft, pearly plates, was collected, washed thoroughly with acetone, and dried, first, by exposure t o warm air and finally in a vacuum desiccator, The yield amounted to more than 90 per cent. of the theoretical.Prepared in this way, the compound was fairly stable ; it was odour- less when dry, and, although deliquescent, was not sufficiently so to preclude its being weighed in an open vessel for analysis. When heated in a narrow tube it melted sharply at 109' with copious effervescence. Chlorine was determined by fusing a weighed quantity with pure caustic soda, and subsequently with nitre ; the product, dissolved in water, was acidified by nitric acid and the mixture treated with excess of N/10 silver nitrate. After most of the nitrous acid had been expelled by boiling, the remainder was destroyed by urea, and the silver in solution determined by Volhardt's method, using N/10 ammonium thiocyanate. I n all the chlorine determinations given later, except where it is otherwise stated, a similar method was adopted : 0.309 required 19.8 C.C.N / l O silver nitrate ; C1= 22.75. C,H70N2C1S requires C1= 22.98 per cent. The substance dissolved very freely in cold water, yielding an acid solution which remained clear on treatment with N/lO caustic alkali, of which two equivalents were required for saturation ; no thiocyanate was present in the neutralised solution : 0.1545 required 19.95 C.C. NjlO NaOH; theory requires 20 C.C. It was considerably less soluble in absolute alcohol, the solution, when warmed with sulphuric acid, developing the odour of ethyl acetate. The aqueous solution yielded with silver nitrate a white precipitate, blackened instantly on the addition of ammonia, and was readily desulphurised by heating with an alkaline solution of lead, with formation of a brilliant mirror of galena.Moreover, the aqueous solution, when evaporated to a small bulk, yielded thiourea, which melted a t 171-172' and was identified by comparison with pure thiourea (m. p. 171-172°) and by the mixed melting point method. The decomposition by water proceeds, therefore, as shown by the equation : C,H70N2ClS + H20 = HCl + CH,*C02H + NH,*C(NH)*SH. Consistently with this, when the aqueous solution was treated in presence of dilute nitric acid with excess of A7/10 silver nitrate, the precipitate collected, and the residual silver determinediby Volhardt's126 DIXON AND HhWTAOlZWE : method, it was found that two molecules of silver salt were absorbed for each molecule of hydrochloride taken; of these two molecules, one combined with the hydrochloric acid and the other formed the molecular additive compound CSN2H,,AgN03, described by Reynolds (Trans., 1892, 61, 251).Claus’ observations were so far confirmed, that in this decomposition by water no sign mas detected of the formation of acetylthiourea ; in other words, the acetyl group is not combined with a nitrogen atom. Another experiment, made by treating one molecular proportion of the bydrochloride, dissolved in anhydrous alcohol, with an alcoholic solution containing one equivalent of sodium, gave a similar result, sodium chloride being precipitated, and the filtrate, by concentration, yielding crystals of ordinary thiourea. I t does not follow, howover, that the acetyl chloride is held merely by some attraction such as that whereby water of crystallisation is retained in certain compounds, for the fact that acetic acid as well as hydrochloric acid is formed on hydrolysis is equally consistent with the view that partition of the acetyl chloride occurs when it unites with thiourea, the chlorine becoming associated with hydrogen and the acetyl group attaching itself to the sulphur atom t o form NH,*C(NH)*S*CO*CH,. Snch a compound is basic in type, in the same sense as NH,*C(NH)*S*C,HS and its congeners, and since the presence of an acetyl group in place of the electropositive alkyl must greatly weaken the basic character, it is quite to be expected that combined hydrogen chloride, if present, should exert towards alkali the same acidity as if i t mere free.I n presence of water the combined acetyl group also displays full activity, as just shown, but considering that this group is eliminated by dilute alkali, even when united with nitrogen in ccb-disubstituted thiocarbamides, it was to be expected that it would very readily be separated from sulphur, for which element (as may be noticed in the case of thiolacetic acid) its affinity i s but feeble.* Moreover, t h a t the acylogen is not held as acetyl chloride of crystal- lisation seems proba.ble from the behaviour of the compound on heating, for if a t 109’ the acylogen simply passod off, thiourea alone should be left, whereas it will be shown later that this is not the case. Furthermore, that hydrogen chloride is held as such, combined in the molecule, may be inferred from the fact that it is possible, + Aectylthinuwn.p r t s vcry readily witli the ncetyl group. Thus, when 1 mole- cule of the piire substance, clissolvcd i n cold water, was m i x d with excess (2 inole- cules) nf &-/lo alkali, mid the solution allowed to stand for ,z ccrtaiii tiinc before titrating back with N/10 acid, WP, fonnd that, after five iriinntes’ standing, seven- tenths of 1 molecule of alkali had been a1 solbed a n d , after tcii minutes, exactly 1 inolecule.THE ACTION OF ACID CHLORIDES ON THIOUREAS, 12'7 as shown i n the following experiment, to replace it by a different acid. To a concentrated aqueous solution of the acetyl compound, slight excess of a saturated aqueous solution of picric acid was slowly added ; the resultant precipitate of minute, yellow, interlacing needles, when thoroughly washed with water and dried, meltod sharply a t 120'. Since the original compound is somewhat readily dissociated by water, with formation of thiourea (which gives no picrate), and the picrat.e itself does not escape hydrolysis, a poor yield was.obtained. The product was free from chlorine; its aqueous solution, when treated with silver nitrate followed by ammonia, gave a black precipitate, and was readily desulphurised by heating with an alkaline solution of lead. That tho acetyl group still remained i n combination was shown by dissolving a portion i n alcohol, acidifying with sulphuric acid, and warming, when the odour of ethyl acetate became distinct : 0.347 gave 0.2354 BaSO,.0.3292 ,, 56.8 C.C. moisf; nitrogen at 14' and 753 mm. N = 20.2. C,H,O,N,S requires S = 9.22 ; N = 20.17 per cent. S = 9.3. Now, a solution of acetylthioiirea in water yields no picrate with aqueous picric acid, it is somewhat sparingly soluble in cold water, and does not dissolve more readily in cold dilute hydrochloric acid ; when picric acid is added to the solution in the latter, no precipitate is formed unless the hydrochloric acid is sufficiently concentrated, in which case picric acid itself crystallises oub. Accordingly, the above substance is the p i c m t e of an acetyl-9-thio- urea, NH,*C(NH)*S*CO*C€I,, isomeric with the compound melting a t 165O, obtained by Nencki (Bey., 1873, 6, 599) from thiourea and acetic anhydride, and by Doran (Trans., 1905, 87, 341) from acetyl- thiocarbimide and ammonia.Action ofNeat.-A quantity was melted in a test tube immersed in a bath of sulphuric acid, the temperature of which mas kept between l l O o and 115'. The liquid bubbled freely, fumes of hydrogen chloride being evolved together with an odour recalling that of thioacetic acid ; it then became brown, and soon began to solidify. After some twenty minutes the effervescence had almost ceased, when the now solid residue was withdrawn from the bath and twice crystallised from boiling water, being obtained i n small, white needles free from chlorine and melting at 166" (corr.). It gave the usual thiocarbamidic reaction (desulphixrisation) with hot alkalino solution of lead, and when heated with alcohol and dilute sulphuric acid developed the odour of ethyl acetate.A specimen of pure acetylthiourea, attached t o the same thermometer, melted a t the same temperature, and when approximately equal weights of the two substances were mixed, t h e128 DISON AND HAWTHOltNE : melting point of the mixture was found to be unchanged; conse- quently the product was acetylthiouren. From the results of these various observations, we conclude that in the additive compound of acetyl chloride with thiourea the acetyl group is united directly to sulphur, the resultan5 molecule being basic, not alone in type, but also to some extent in character, and that when heat is applied the acetyl group migrates to a nitrogen atom so as to yield ordinary acetylthiourea : NH,*C(NH)*S*COiMe,HCl= HCl + N H: C(NH*COMe)*SH. It may be that this transference of the group named occurs as the primary effect of heat, in which case the rosultant acetylthiourea, being for all purposes non-basic, could not retain the hydrogen chloride previously held by the molecule of more basic configuration and character ; or possibly the hydrogen chloride, being feebly held by so weak a base, is parted reczdily from it by increase of temperature ; if so, the wandering of the acetyl group from sulphur t o nitrogen, for which i t has much more affinity, might occur readily enough. At present it is not easy to decide between these hypotheses, but in view of the observation previously mentioned, that withdrawal of the combined hydrogen chloride by means of a single equivalent of sodium ethoxide fails to produce acetylthiourea, there is at least some ground for believing that in this case the transfer of the acetyl group from sulphur to nitrogen is not conditioned independently of tempera- ture.The mechanism of this additive change being so far explained, we may now describe the results of experiments made with other thio- iireas and acylogens. Acetpl Chloride and PhenyMiourea. On mixing finel y-divided phenylthiourea, suspended in benzene, with excess of acetyl chloride, union occurred immediately without material rise of temperature, the product, the yield of which amounted to 93 per cent. of the theoretical for a molecular additive compound, being apparently crystalline. The same compound, but in a state of higher purity, was obtained by adding considerable excess of acetyl chloride to a tepid, concentrated solution of the thiourea in acetone.On cooling t'his mixture, lustrous, white, flattened prisms were deposited ; these were colourless when dry, and melted, if quickly heated, a t 94" with copious effervescence. The melting point is dependent on the duration of heating, becoming markedly lower if this is prolonged : 0.2305 gave 0.2345 BaSO,. 0.2305 required 20.2 C.C. N/10 AgNO,. 8 = 14.0. C,H,lON,CIS requires S = 13.88 ; C1= 15.40 per cent. C1= 15.7.THE ACTTON OF ACID CHLORlDES ON THIOUREAS. 129 When treated with sulphuric acid the solid additive cornpound effervesced, evolving fumes of hydrogen chloride. It was freely soluble in cold water, yielding an acid solution, from which, if not too dilute, prismatic crystah of plienylthiouren separated ; in the aqueons mother liquor both hydrochloric and acetic acids were present, but no thiocyanic acid.It is plain t h a t in the additive compound the acetyl group is not directly associated with llitrogen ; otherwise scetylphenylthiocarb- amide (either aa- or ab-) must be produced by hydrolysis on contact with water. The possibility of acetyl chloride being held in some sort of mechanical combination was negatived, just as in the case of the corresponding thiourea derivative, by the observation t h a t the hydro- chloric acid may be eliminated and a picrate of the " base '' may be obtained. Owing to the ready dissociation of the original compound by water, its aqueous solution must lie combined quickly with the picric acid ; otherwise little or no picrate is formed ; moreover, the picrate itself, although tolerably stable when once obtained, is dissociated by much water if this is present when combination takes place.The picrute was obtained in minute, lemon-yellow needles, becoming highly electrical on friction ; they were free from chlorine, almost insoluble in cold water (but dissociated by boiling with it.), and melted to a deep bromine-coloured liquid a t 187-1 8S0, with previous darkening. The substance was decomposed by warming with caustic potash, and hence was desulphurised when heated with an alkaline solution of lead : 0,4113 absorbed 19% C.C. N/lO barium chloride. S = 7.7. C,5H,,0,N,S requires S = 7-56 per cent. Ordinary substituted thioureas and thiocarbamides (that is, those i n which the substituting radicles are attached t o nitrogen) do not yield picrates readily, if at all.Thus, when ccb-acetylphenylthiocarb- amide, dissolved in acetone, was treated with an aqueous solution of picric acid, brilliant plates were deposited ; these, however, became pearly white on washing, and proved on examination t o be nothing more than the unaltered thiocarbamide, precipitated by t h e water used as solvent. Neither was it found possible t o combine picric acid with an-acetylphenylthiocarbamide, AcPhN*CS*NH,, dissolved in alcohol, acetone, or water. In a further experiment, made by leading a large excess of dry hydrogen chloride through a nearly saturated solution of the cca-compound in cold acetone, no hydrochloride was pre- cipitated, nor, after evaporating t h e solution t o a pasty consistence and removing some oily product (having an odour of mercaptan) by washing slightly with alcohol, did the solid residue contain any chlorine ; it consisted, in fact, of the original thiocarbamide, nearly pure.130 DlSON AND IIAWTHORKE : Phenylthiourea, in water or alcohol, gave no picrate ; moreover, when dry hydrogen chloride was led through its solution in acetone, no solid was produced ; instead, hydrogen sulphide escaped, and the residual liquid had a strong odour of mercaptan.So far as may be judged from these experiments, i t seems a justifiable conclusion that mono- and di-substituted thioureas or thiocaybamides are almost devoid of basic characters, but that a molecule having the configuration NH:C(SH)*NH, becomes basic when an organic radicle is substituted for the SH hydrogen, and does so independently of whether the sub- stituting radicle is itself electropositive or electronegative, this cbaracter affecting merely the strength of the resultant base.For the various reasons set forth above, we infer that the additive product of acetyl chloride and phenylthiouren is tt definite chemical compound, namely, the hydrochloride of an acetylated phenylthiourea, in which the acetyl group is joined to the rest of the molecule through the sulphur atom ; otherwise, iminoacet~ylthiolplienylcarbamic acid, or, according t o the nomenclature suggested by one of us (Trans., 1895, 6'7, 5 64), acetyl- q-v-phenylthiourea, C6H,NH*C(NH) * S*CO*CH,.This represents a typical basic form 01- peeudothiouren, analogous to the known derivatives, having distinctly positive radicles attached to the sulphur at'om. AS a rule, members of the latter class are hydro- lysed more o r less readily by alkali, that is, as soon as the combined acid is withdrawn, but in such cases the sulphur atom passes off in combination with the alkyl group as meroaptan. Action of HecLt.-A quantity of the hydrochloride contained in a test- tube immersed in a bath of sulphuric acid mas heated slightly above its melting point until the effervescence (due principally to the escape of hydrogen chloride) ceased; the liquid, which had an odour of thio- acetic acid, now gradually solidified, and the residue, on crystallisation from boiling water, separated in glistening leaves melting at 170-171° and consisting of ab-acetylphenylthiocarbamide. Heat, therefore, just as in the case of the corresponding thiourea derivative, brings about a movement of the acetyl group from the sulphur to one of the nitrogen atoms, whilst the molecule changes in configuration from the imino- tbiocarbamic to the thiocarbamidic form.Action of AZ?caZi.-Attempts to neutralise the dilute aqueous solu- tion with standard alkali failed to give concordant results owing to the difficulty of attaining a definite end point ; it was noticed, however, that if the alkali was run in quickly, before phenylthiourea had time to separate from tho aqueous solution, and tho now turbid mixture mas cleared by warming, the liquid, as it cooled, deposited first brilliant plates and then phenylthiourea in needles or prisms.When tho solid was added directly to a slight excess (about 2 molecules) of N/10 alkali and the mixture warmed uptil it became clear, the solution, ODTHE ACTION OF ACID CHLORIDES ON THIOUREAS, 131 cooling, deposited only the brilliant spangles ; these were devoid of bitter taste and consisted of ab-acetylpbenylthiocarbamide (m. p. This transfer of the acetyl group to nitrogen seems to take place only with the ready formed hydrochloride, for when phenylthiourea was crystallised from solutions containing sodium acetate and chloride, or acetic and hydrochloric acids, or from the latter mixture after neutral- isation by alkali, no sign could be detected of the production of nb-ace tylphenyl thiocarbamid e.Moreover, when phenyl thiourea, dis- solved in weak caustic alkali (2 molecules), was treated with excess of acetyl chloride, the solution, on cooling, deposited nothing but un- changed phenylthiourea. The symmetrical or ab-thiocarbsmide, then, is formed on removal of the combined hydrogen chloride, whether this be effected by heat or by the action of caustic alkali in excess. That a transfer of the acyl radicle from sulphur to nitrogen should take place under the influence of heat is not surprising, a number of cases having now been observed of the movement of a n acid group from one nitrogen atom to another within the thiourea molecule. Thus, for instance, Wheeler has shown (Amer. Chetu. J., 1902, 27, 270) that aa-acetylphenylthiocarbamicle, AcPhN*CS*NH, (compare Hugershoff, Ber., 1899, 32, 3649), is changed by fusion into the nb-compound, AcNH*CS*NHPh, and Johnson and Jamieson (ibid., 1906, 35, 297), that various acyl-$-thioureas, for example, Ez,N*C(SAle):NH, undergo a like change, one acyl group moving from its original attachment in the amino-position and becoming united a t the imino-group.I n the case of our acylphenyl derivative, heat appears to determine that change whereby the most stable configuration is produced. On the other hand, that che presence of dilute caustic alkali should lead under such mild conditions to the same ultimate result was both unexpected and puzzling. Water, as previously stated, removes the acetyl group from the hydrochloride, thereby producing phenylthiouren ; and since phenylthiourea, in contact with alkali, resists acetylation by acetyl chloride, the final change, however accomplished, could scarcely be accounted €or by initial hydrolysis of the additive compound into its original constituents.Presumably, therefore, the formation of n6-acetylphenylthiocarbamide must be explained either by some change occurring in the $-base itself, when liberated from its hydrochloride, or else through some influence exerted on the former by the alkali. This could obviously be tested by removing the combined hydro- chloric acid under conditions such as to preclude the resultant organic product from exposure to tho action of free alkali, and noting if the product was still the same. The first experiment in this direction mas conducted by adding 170-1 7 1").132 DIXON AND HAWTHORNE : gradually to a solution of the hydrochloride (1 molecule) in nearly anhydrous alcohol, one equivalent of sodium previously dissolved in a separate portion of the same solvent, any material rise of temperature being prevented.The precipitate of sodium chloride was separated, and the clear, strongly acid filtrate allowed t o evaporate spontaneously ; t h i s liquid gave no reaction for thiocyanic acid, thereby differing from solutions which had been treated with alkali to neutrality or in excess. On concentration, white crystals were deposited, free from chlorine, somewhat sparingly soluble in water, and containing both thiocarb- amidic sulphur and the acetyl group. Our hope that dissociation of the original compound would be avoided by the use of strong (99 per cent.) alcohol instead of water was not realised, for the product melted very indistinctly at 129-132" and had a bitter taste, which proved t o be due to its containing a very appreciable quantity of phenylthiourea.By means of cold chloroform, in which it is almost insoluble, the latter mas separated ; the chloroform was then evaporated, and the residue, when crystallised from dilute alcohol, obtained in long, pointed prisms, melting, if rapidly heated, at 139O. The alcoholic solution darkened gradually when mixed with neutral silver nitrate or at once on treat- ment with the nmmoniacal nitrate ; desulphurisation occurred readily on boiling with an alkaline solution of lead. The presence of an ncetyl group was proved by warming the substance with alcohol and sulphiiric acid, when the odour of ethyl acetate became distinct.I n the second experiment, the hydrochloride, dissolved as before in strong alcohol, was treated with pure, dry calcium carbonate; when the effervescence had ceased, the unattacked carbonate was removed by filtration, and on evaporating the filtrate to a small bulk a t the atmo- spheric temperature, precisely the same results were obtained as when the hydrochloric acid was eliminated by means of sodium ethoxide, the purified end product resembling in every respect t h e Substance melting a t 139' previously described. A sulphur determination gave the figures required for the free " base," PhNH*C(NH)*S*CO*CH,, or for its isomeride, ab-acetyl- phenyl t hiocarbamide, PhNH CS-NH *CO C H, : 0.194 absorbed 20.1 C.C.X / l O barium chloride. S= 16.6. C9H,,0N,S requires S = 16.50 per cent. This substance, however, could not be ah-acetylphenylthiocarbamide, which crystallises in brilliant leaves melting a t 170-171", neither, on account of its comparatively high melting point, could it well be the '' base '' formulated above, since a compound having t.he structure of the latter might be expected to melt at about 50". h t as the phenyl group is undoubtedly attached to nitrogen, t h e only remaining isomeride proper to this series is a thiourea or thiocarbamide havingTHE ACTION OF ACID CHLORIDES ON TIIIOUREAS. 133 both the phenyl group and the acetyl group attached to the same nitro- gen atom, that is, assuming the compound to be a thiocarbamide, AcPhN.CS*NH,.That the substance in question had this composion was made certain by the following observations : (1) when heated a t or slightly above its melting point it presently resolidified, being converted by the fusion into the isomeric ab-acetplphenylthiocarbamide ; (2) when dissolved in weak aqueous caustic alkali it yielded the last-named symmetrical compound; (3) when treated with strong alkali the acidified mixture gave an intense reaction for thiocyanic acid. These are the properties of the substance obtained by Hugershoff (Zoc. cit.) by dissolving phenyl- thiourea in acetic anhydride at 80’ ; to this he incorrectly assigned the symmetrical or ab-formula, an error subsequently corrected by Wheeler (Zoc. c i t .) , who placed beyond doubt the fact of its being an aa-deriv- ative. The chemical identity of our product with that of Hugershoff was further established by the observation that a specimen of his com- pound, prepared according to his directions, melted, within a degree, at the same temperature as ours, and when the two were mixed in equal proportions the melting point underwent no perceptible change. These experiments show that caustic alkali determines by its presence a change in the product initially formed by the removal of the coni- bined hydrochloric acid from our hydrochloride, since if this removal is effected with a limited quantity of alkali, or in the absence of any alkaline substance, the product is not identical, but isomeric with that obtained in presence of excess of alkali, and the former product, when isolated and then brought into contact with free alkali of a certain strength, is changed into the latter [see (2), above].(i) Phenylthiourea is not acetylated, in presence of alkali, by treat- ment with acetyl chloride, but (ii) Acetyl chloride unites spontaneously with phenylthiourea to form the hydrochloride of a feeble ‘( base,” acetyl-$-v-phenylthiourea, PhNH*C(NH)*SAc. (iii) This base, when liberated in alcoholic solution, undergoes isomeric change, the acetyl group migrating, a t the ordinary tempera- ture, to the phenylated nitrogen atom to form PhAcN*CS*NH,. (iv) The last product, if heated or if brought into contact with dilute alkali, undergoes f urtiher isomeric change, the phenyl and acetyl groups now becoming att,ached to different nitrogen atoms, and thus yielding AcNH- CS N HPh.(v) The hydrochloride (ii) changes by melting, with loss of hydrogen134 DXXON AND BAWTHORNE : chloride, into AcNH*CS*NHPh’; by solution in cold water it yields phenylthiourea. This succession of movements of the acetyl group is exhaustive ; the acetyl, combined at first with sulphur, can be driven to the phenyl- amino-group, and thence, by an easy transition, to the remaining nitrogen atom; in other words, it may occupy in succession, and in a given existing plienyl thiourea molecule, every place where, according t o our present notions, i t could conceivably be attached. No less than six distinct forms of acetylphenylthiourea may be formulated, namely, AcPhN*CS*NH,, PhNHICS-NHAc, NHPh.C(NAc)*SH, NHPh*C(NH).SAc, NHAc’C(NH)-SPh, and AcPhN*C(NH)*SH ; these are all essentially different, and do not include mere tautomeric variants (for example, PhNH6C(NH)*8Ac +X NH,*C(NPh)hSAc), and.there doea not a t present seem to be any valid reason for supposing that any one of them is incapable of existence. Nevertheless, in view of the free mobility of both hydrogen and acetyl in this very “ plastic ” molecule, it will doubtless be no easy matter to prepnre and to keep the three forms which still remain unknown. Of these, one contains the aryl group combined with the sulphur atom; it may be noted in passing that all attempts hitherto made to fix the aryl group in this +-form have been unsuccessful (see Trans., 1906, 89, 909).I n reference to Hugershoff’s observation that acc-thiocarbamides containing one acyl and one aryl group yield thiocyanic acid on treat- ment with strong alkali, AcPhN*CS*NH, + KOH = AcNHPh -I- IiSCN + H,O, a number of experiments wore made in order t o learn if this property is peculiar to members of that class. The compounds examined included (i) monosubstituted thioareas, both acvl and alkyl ; (ii) di- substituted thiocarbamides, ua- and ab- of the alkyl or aryl series, or of mixed varieties, and ccb-derivatives of the acyl-alkyl or acyl-aryl class ; (iii) trisubstituted thioureczs derived from acyl, aryl, and alkyl thiocarbimides by combination with secoiidsry bases of various sorts. Without giving a detailed list of a11 the substances employed, it may suffice to say that riot one of them afforded the slightest reaction for thiocyariic acid when treated with alkali followed by hydrochloric acid and ferric chloride.On the otlier hand, our acetyl-$-v-phenylthiourea hydrochloride reacted readily for it, owing to partial conversion into Hugershoff’s compound, and the same is true of the various additive compounds from acylogens and monosubstituted thioureas, which we describe in the following pages. This test, therefore, appears to be a characteristic one for compounds of the class named. It is stated above that acc-acetylphenylthiocarbamide melted a t 1 3 9 O , the temperature recorded by Hugershoff (Eoc. cit.) for this compound. Nevertheless, we had a t first much difficulty in reconciling the meltingTHE ACTION OF ACID CHLORIDES ON THIOUKEAS.135 point of our product with that given by him, or indeed, in arriving at any really definite melting point. This was ultimately found to be due to the slowness with which we conducted the heating, for on working rapidly, the substance melted a t 139". At our own slow rate, not only did the substance melt at temperatures varying in different determinations from about 133O to 137", but also, when a specimen of Hugershoff's compound (prepared from acetic anhydride according to his directions) was heated a t the same time as ours, it showed a like behaviour. Moreover, the substance, if heated for some time a t 129") gradually softened, but did not liquefy, and on raising the temperature, no further change could be observed until between 150" and 160' or even a trifle higher, when i t melted to a clear liquid.It appeared doubtful, therefore, whether the compound really possessed a true melting point, for, since a t a temperature many degrees below that of liquefaction, considerable change may occur within not many minutes (into the ab-compound), it was t o be expected that at about 139O this change mould be very rapid, Such, in fact, is the case, for if the compound, heated quickly, was removed the instant it liquefied and cooled a t once, the now solid material, when put back into the appardtus, even at 145", no longer melted, thus showing that the process of conversion had gone far. The solidified product also, when tested with alkali, gave but a trifling reaction for thiocyanic acid.Now although the rate of change is very rapid indeed a t the liquefy- ing point, it is considerably retarded at temperatures not far removed from this, and hence it seemed probable that the liquefaction was con- ditioned, not by the melting of the na-compound, with subsequent change to the ab-form, but through the production of a mixture of both in proportions continuously varying, so that a t some particular moment the most fusible mixture would result ; in which case, if the tempera- ture was high enough, it must melt. Two narrow tubes, as nearly equal in all respects as possible, were charged to the same depth with two fine powders, one consisting of the cba-corn- pound, the other of a substitnee melting at 141-142'. The bath being kept steadily a t 143", both tubes were immersed simultaneously and attached to the same thermometer. I n ten seconds, the substance of higher melting point liquefied suddenly; after a total interval of forty-five seconds, the nu-compound, which meanwhile had scarcely changed in appearance, also suddenly melted.Ten seconds, therefore, were required for the establishment inside the tubes of a temperature not less than 141-142", which is above the maximum '' melting point " of the un-derivative j presumably the remaining thir ty-five seconds were occupied, not in melting it, but in effecting such a relative amount The following experiment peems to confirm this view.136 DIXON AND EIAWTI1OIINE : of conversion as to produce a mixture fusible a t the temperature already attained within the tube.Acetyl Chloride and o-Tolylthiourea. When to a saturated solution of o-tolylthiourea in cold acetone rather more than the calculated quantity of ncetyl chloride was added, and the mixture cooled, a crystalline, white solid was soon deposited, melting a t 96" with effervescence ; the same product was obtained, with evolution of heat, by mixing the constituents in presence of benzene, the latter method giving 95 per cent. of the theoretical yield for a molecular additive compound : 0.2445 required 9.8 C.C. N/lO silver nitrate. C1=14.2. C,oH,,0N2S,HCl requires CI = 14.50 per cent. The pure substance dissolved readily in cold water, yielding an acid solution, from which in a short time white crystals of o-tolylthiourea began to separate ; in the solution both hydrochloric and acetic acids were present, but no thiocyanic acid.When heated slightly beyond its melting point i t effervesced freely, evolving fumes of hydrogen chloride ; the liquid now resolidified, and the solid, when recrystallised from boiling alcohol, in which i t was rather sparingly soluble, formed brilliant prisms. The cold alcoholic solution gave immediately, with aqueous silver nitrate, a black pre- cipitate, and had an odour of ethyl acetate when warmed with . sulphuric acid. The melting point of this new product, 1 S2- 1 8 3 O , was less than a degree below that of a specimen of pure ab-acetyl-o-tolyl- thiocarbamide, and when equal weights of the two were mixed, the melting point of the mixture was still 182-183". I n this case, therefore, as in that of the phenylic homologue, mith- drawal of the combined hydrochloric acid by heat is associated with movement of the acetyl group from sulphur to nitrogen, acetjl-$-o-tolyl- thiourea hydrochloride changing to ab-acetyl-o-tolylthiocarbamide, NHPh*C(NH)*SAc,HCl= HC1+ NHPh*CS.NHAc.The solution of the hydrochloride, i f mixed without delay with aqueous picric acid, gave a yellow picrate in minute needles. By treating the hydrochloride, dissolved in absolute alcohol, with one equivalent of sodium ethoxide, separating the precipitated sodium chloride, and treating the crystalline residue left by evaporation of the alcohol, as described in the corresponding experiment with the phenyl derivative, white prisms were obtained melting a t 139.5". They were free froin chlorine, gave the usual desulphurisation reactions with lead and silver salts, and when treated with strong alkali yielded a pasty mass, redcting abundantly for tliiocyitnic acid. TI& product wdsTHE ACTION OF ACID CHLORIDES ox THIOUREAS.137 obviously .Hugershoff's aa-wetyl-o-tolylthiocarbamide, melting point 140' : 0.208 gave 0.3318 BaSO,. S= 15.3. C,H,,ON,S requires S = 15-38 per cent. It may here be noted that the hydrochloride, both on heating and on treatment with sodium ethoxide, had an odour of thioacetic acid, owing probably to partial decomposition of the I' base " when liberated : U,H,*NH*C(NH)*S*(:OIe = C,H,*N:C:NH + COMe*SH. Acetyl Chloride ccncl p-Tolylthiourecc. p-Tolylthiourea is so sparingly soluble in acetone that the precipita- tion method is not well suited for preparing the additive compound except on a small scale ; when obtained in this way it formed lanceolate prisms.It was prepared in larger quantity by mixing together the finely-powdered thiourea and acetyl chloride, whereupon sufficient heat was evolved to evaporate R portion of the latter ; the mixture was then ground up in a mortar, the solid collected a t the pump, washed with light petroleum, and dried in a vacuum, The melting point was 102-103' with much effervwcence, and the yield amounted to 80 per cent. of the theoretical : 0.2445 required 9.8 C.C. NI10 silver nitrate. C1= 14.2. C,,H,,ON2S,HC1 requires C1= 14-50 per cent. If not contaminated with unchanged p-tolylthiourea (which may be extracted by repeatedly shaking the powder with acetone) the hydro- chloride dissolved readily in water, the solution quickly becoming turbid from the separation of p-tolylthiourea ; no thiocyanic acid was contained in the liquor. The thiourea melted at 181'; Staats (Ber., 1880, 13, 136) gives 1S2'.When the hydrochloride was treated with cold aqueous caustic alkali the mixtur; reacted readily for thiocyanic acid, thereby showing the formation of the ua-acetyl-pt,olylthiocar bamide. Acelyl Chloride uncl ab- Diphen ylthiocarbamicle. According to Deninger (Bey., 1895, 28, 1322), thiocarbanilide cannot be acotylated by the Schotten-Baumann method ; similarly, we found (see p. 131) that phenylthiourea is not acetylated by acetyl chloride in presence of caustic alkali. When, however, diphenylthiocarbamide, suspended in benzene, was mixed with excess of acetyl Chloride, the solid gradually changed to a clear, yellow oil, which crystallised on standing.The product, when powdered and washed thoroughly with benzene, was a white powder, fuming in moist air, and having an odour of hydrochloric acid; i b VOL. XCI. L138 DIXON AND HAWTHORNE : was apparently insoluble in water, and began to decompose, with effervescence, at about 106" : 0.3065 absorbed 9.7 C.C. N/lO silver nitrate. The yield amounted to only 50 per cent. of that calculated for R molecular additive compound. Dilute alkali withdrew all the com- bined acid, leaving thiocarbanilide. The compound of diphenylthiocarbamide with acetyl chloride is dis- tinctly less stable than that of monophenylthiourea, since the former evolves visible fumes when exposed to moist air, whilst the latter does not, Acetyl Chloride and di-o-170lyZthiocccrbamide. On mixing these together, using excess of acetyl chloride, a yellow liquid was formed; this, when treated with light petroleum, gave a paste which presently solidified.The product, when broken up and dried, had little odour, and melted sharply, with copious effervescence, at 135-136O : C= 11.24. C15H150N,CIS requires C1= 11.58 per cent. 0.3345 required 9.7 C.C. NjlO silver nitrate. 0,3345 gave 0.262 BaSO,. C1= 10.3. S = 10.8. C17Hl,0N,C1S requires C1= 10.6 ; S = 10.45 per cent, Benxoyl Chloride and Thiourea. These substances combined at once in presence of benzene to form a white powder melting a t about 116' ; the yield was poor, amounting to only 54 per cent.of the theoretical : 0.2165 required 9.7 C.C. N/10 silver nitrate. C1= 15.9. C,H,ON,S,HCl requires C1= 16.4 per cent. When the combined acid was removed by adding calcium carbonate t o a solution of the hydrochloride in 99 per cent. alcohol, no benzoyl- thiourea was found in the filtrate, but ordinary thiourea instead ; this behaviour is similar to that observed in the case of the corresponding acetyl compound (see p. 126) when treated with a limited amount of sodium ethoxide. Reference has already been made to Pike's observation that thio- urea and benzoyl chloride i f heated to 120' yield benzoylthiourea; an attempt was therefore made to ascertain whether the latter substance would be produced by heating the above additive compound, A quantity was melted in a test-tube, immersed in a sulphuric acid bath : hydrogen chloride and a little hydrogen sulphide were evolved, and soon the mass solidified; the temperatiire was now raised to 126' to complete the action, and after some five minutes the tube was removed and cooled, The product, nearly insoluble in cold water,THE ACTION OF ACID CHLORIDES ON THIOITREAS.139 was boiled with a large quantity of this solvent and the solution filtered from a trace of pasty solid. The filtrate crystallised imme- diately, giving small, vitreous prisms which dissolved readily in cold alkali; this solution, when nixed with a lead salt and heated, was desulphurised with formar,ion of a speculum of lead sulphide. The solid had an intensely bitter taste; it was easily soluble in hot alcohol, somewhat sparingly so in cold, and the solution, when warmed with sulphuric acid, had an odour of ethyl benzoate. It crystallised from boiling water in needles melting a t 169-170°, and hence con- sisted of benzoylthiourea, which melts according to Pike (Zoc.cit.) at There can be no doubt as to the position of the acyl group in benzoylthiourea, since lsliquel has shown (Ann, Chim. Phys., 1877, [v], 11, 313) that it is produced from benzoylthiocarbirnide and ammonia. By heating tho additive compound, therefore, it loses hydrogen chloride, and the benzoyl group thereupon transfers itself from the sulphur to one of the nitrogen atoms. Benzoyl chloride gave with phenylthiourea a tenacious paste ; with o-tolylthiourea it yielded a solid additive product which was not examined in detail, 169 -1 70'.Benxoyl Chloride and p- ToZyZtAiourea. By direct union of these constituents a soft, white powder, decom- posing with effervescence at 137--138O, was obtained in nearly quantitative yield. The substance melted in boiling water, and the filtrate, on cooling, deposited long needles, which mere, apparently, benzoic acid. It was desulphurised by alkaline solution of lead, and when warmed with alcohol and sulphuric acid gave the odour of ethyl benzoate : 0.613 required 20.1 C.C. , ! l o silver nitrate. C1= 11.6. C,,H,,ON,S,HCl requires C1= 11 -5 per cent. On warming the substance with caustic alkali and treating the resulting mixture with hydrocliloric acid, followed by ferric chloride, a blood-red coloration appeared ; as this reaction points in the case of acetyl derivatives of monosubstituted thioureas to the presence of an aa-disubstitution compound, it seemed probable that the thiocyanic acid yielded by the benzoyl derivative had a like origin.Hugershoff does not appear to have inquired whether the benzoyl radicle is similar to the acetyl group as regards the power of forming labile thiocarb- amides ; me therefore conducted the following experiment to learn whether, from our supposed bsnzoyl-$-v-tolylthiourea hydrochloride, C,H?*NH*C(NH)*S*COPh,HCL, an acc-derivative could be produced, PhCO*N( C,H,)*CS*NH, [or perhaps PhCO*N( C,H,) C( NH) *SH], con- L 2140 DIXON AND HAWTHORNE : vertible in turn into the known nb-benzoyl-p-tolylthiocarbamide, PhCO*NH*CS*NH*C,H,. From a quantity of the freshly-prepared hydrochloride, disscjlved in cold anhydrous alcohol, the combined acid was withdrawn by excess of calcium carbonate, the filtered liquor mas then evaporated, and the solid residue purified by chloroform i n the manner previously described for the corresponding acetylphenyl derivative.The viscid solid, left by evaporation of the chloroform, was treated with pure ether, which separated it into (1) a residue, giving no thiocyanic reaction with alkali, and melting after one recrystallisation from alcohol a t 167-15S0, and after a second a t 158-159P (uncorr.), and (2) a filtrate. The latter on evaporation left a solid, reacting with alkali for thiocyanic acid. On crystnllising this from alcohcl, needles melting a t 157-158' were obtained, resembling the preceding and giving no thiocyanic reaction; moreover, the liquor from these now reacted but faintly with alkali for thiocyanic acid. The substance melting a t 158-159" proved to be a thiocarbamide containing the benzoyl group, and since it gave no thiocyanic acid, was presumably not the acb- but the ah-compound, namely, benzoyl-p- tolglthiocarbamide.This melting point is materially lower than that recorded by Miqnel (Zoc. it.)^ namely, 165'. On preparing Miquel's compound, however, by his own method (from benzoylthiocarbimide and p-toluidine), and recrystallising from alcohol until the melting point became constant, a substance was obtained identical in appear- ance and properties with that described above, and melting sharply at the same temperature, 158-1 59' (uncorr.).Bliquel's figure, there- fore, is somewhat too high. So far as may be judged from the single set of experiments detailed above, it would seem that the hydrochloride of benzoyl-$-p-tolylthio- urea can yield, by the elimination of its combined hydrochloric acid, uu-benzoyl-p-tolylthiocarbamide, but that the latter, being rather unstable, is resolved by successive recrystallisations from hot alcohol into the stable or tcb-isomeride, PhCO*NH-CS*NH*C,H,. Benxogll Chloride and Thiocarbani title. When brought together in presence of benzene these substances did not appear t o unite, but on mixing them together directly there was vigorous combination, with considerable evolution of heat. After being washed with benzene, Followed by light petroleum, the product was slightly yellow, and decomposed a t 10S-109°.Yield, 90 per cent. of the theoretical. This substance was distinctly unstable, the loss of material being perceptible during the process of weighing out for analysisTHE ACTION OF ACID CHI,ORIDE;S ON THIOUREA~. 141 0.3784 required 9.5 C.C. N/10 silver nitrate. C,,H,,ON,ClS requires Cl = 9.6 per cent. I n addition t o the experiments described above, the following substances were examined as t o their power of combination when mixed together : C1=8*9. Acetyl chloride and ab-acetylphenylthiocarbamide. Acetyl chloride and ab-benzoyl-o-tolylthiocarbamide. Ethyl chlorocarbona te and tcb-benzoyl-o-tolylthiocarbatnide. Ace ty 1 chloride and carboxy-o- t oly 1 thiourea, C,H7*C0,*NH* C(NH) *SH.Ethyl chlorocarbonate and earboxy-o-tolylthiourea, C7H7*C0,*NH*C(NH)*SH. o-Tolylchlorocarbonate and carboxy-o-tolylthiourea, C,H,* CO,*NH* C(NH)*SH. No action seemed to occur ; in each case tho thiocarbamide employed was recovered and its melting point verified. The presence of an electronegative group in a thiourea appears, therefore, to paralyse, or at least greatly to hinder, its power of combining with acylogens. I n all the preceding cases of combination the radicle R*CO* of the acid chloride employed was highly electronegative in character. With the chloride R*O*COCl, Lhe radicle of which is much more electro- positive, the products as a rule were comparatively stable. Thus, ethyl and methyl chlorocarbonates, when united with thiourea, gave compounds which did not appear to be dissociated by cold water to any material extent, whilst the compounds of methyl chlorocarbonate with phenyl-, o-tolyl-, and p-tolyl-thiourea respectively, were not dis- sociated at all; in fact, when treated with caustic alkali, their solu- tions yielded the corresponding bases, for example, PhNH* C( NH) * S.CO* OMe (Dixon, Trans., 1903, 83, 550).The hydrochloride obtained from thiourea and phenyl chlorocnrbonate (Dixon, Trans., 1906, 89, 909) is a well-marked salt; the kiase, however, could not be isolated by means of alkali, probably because of the feebly positive character of the radicle PhOaCO. Now, if it be true that the general stability of these combinations, and in particular their power of resisting the hydrolysing action of water, depends mainly on the nature of the acyl radicle united with the sulphur atom; it should he possible, by employing acylogens con- taining groups less strongly negative than acetyl and its congeners, t o obtain hydrochlorides proportionately more stable in the sense named than the above.We have tested this conjecture experi- mentally, anci so far as may be judged from the following results it appears on the whole to be substantiated. Of acylogens suitable for the purpose, no abundant choice was avail-142 DIXON AND HAWTHORNE : able ; we selected for investigation the chlorides of certain substituted carbamic acids, R,N*CO*OH, since the group R,N*CO* is distinctly less negative than the acetyl group. Diphen~lcarbccmic Chlode and Thiourea.liolecular proportions were thoroughly mixed and heated in an oil- bath until liquefaction commenced and a trace of effervescence set in ; a t this stage the temperature of the bath was 134'. When cool, the solid residue was powdered, boiled with acetone (which dissolves it to a very appreciable extent), filtered, and washed with more cold acetone; the yield of nearly white powder reached only 55 per cent. of the amount calculated from the equation but a further considerable quantity separated from the acetone solution, The hydrochloride was moderately easily soluble in warm water ; it crystallised from this solvent in short, vitreous prisms having a some- what greasy lustre and melting, with copious effervescence, at 182- 183' (uncorr.) : Ph,N COCl + NH,*C( NH) S H = NH, C( NH) S C 0 NPh,,HCl , 0.3075 required 9.9 C.C.NjlO silver nitrate ; C1= 11.4. C,,HI,ON,CIS requires C1= 11.54 per cent. Water, therefore, did not destroy the salt, The aqueous solution was neutral to litmus; when treated in the cold with rather less than one equivalent of normal alkali, it gave a crystalline white precipitate, which consisted, not of the expected free base, but of diphenylamine; cold alkaline solution of lead gave with the liquor a black precipitate, thus showing that the disruption of the molecule had gone far. When treated with dilute nitric acid or with a solution of potassium nitrate, the aqueous solution of the hydrochloride yielded a crystalline, white precipitate ; the latter, by recrystallisation from boiling water, was obtained in clear, colourless, ffattened, oblique prisms free from chlorine, darkening a t 170°, and frothing a t 176-177".That this substance was a nitrate was shown both by the ferrous sulphate test and by the fact that on warming it with dilute alkali and then treating the mixture with sulphuric acid, a splendid indigo-blue coloration appeared ; this is explained by the liberation by the alkali of diphenyl- amine, which in presence of a nitrate and sulphuric acid gives the well- known blue diphenylamine reaction : 0.334 required 20.5 C.C. N/lO barinm chloride ; 8 = 9.8. C,,H,,ON,S,HNO, requires S = 9.58 per cent. Aqueous picric acid, when mixed with a cold saturated solution ofTHE ACTION OF ACID CHLORIDES ON TMIOUREAS. 143 the nitrate, gave the corresponding picrate in minute, yellow needles rather sparingly soluble in boiling water. Pl~en?lZmethyZctarbanaic Chloride and Thiourea.Combination occurred on the water-bath, and after treatment with acetone, as described in the preceding case, the yield of white solid reached 63 per cent. of tho theoretical; the product melted with effervescence a t about 1 7 5 O , and when dissolved in water gave a neutral solution. Chlorine was determined by acidifying the aqueous solution with nitric acid, filtering, and treating the filtrate according to Volhardt's method : 0.2445 required 9.65 C.C. N/lO silver nitrate ; C1= 14.0. C,H,,ON,ClS requires C1= 14.47 per cent. On adding dilute nitric acid (or potassium nitrate) to the aqueous solution the nitrate was precipitated, which crystallised from boiling water in white, lustrous needles, becoming yellow at 155O, and melt- ing with effervescence to a black liquid at 162".The solution was desulphurised by boiling with ammoniacal silver nitrate, and gave the usual reactions for nitric acid : 0.272 required 20.45 C.C. -@/lo barium chloride ; S = 12.0. The picrate crystallised from water in small, yellow needles melting C,H1lON,S,HNO, requires S = 11.76 per cent. with effervescence a t 174-175". Pheny~et~y~car6~6~n~c Chloride and Thiourea. Prepared by warming the constituents on the water-bath and treating as previously described; the nearly white product melted at 160° with effervescence : 0.2595 absorbed 9.9 C.C. ,V/10 silver nitrate ; C1= 13.9. 0,2595 ,, 9.9 C.C. .V/lO ,, C1= 13.9.0,2595 ,, 19.S C.C. iV/lO barium chloride; S= 12.2. C,,H,,ON,CIS requires C1= 14.07 ; S = 12.33 per cent. The nitrate, precipitated as before, crystallised from boiling water in vitreous prisms changing in appearance at 145", and melting with frothing and green coloration at 154' : 0.2595 required 18.7 C.C. N / l O barium chloride ; S = 11.5. C,oHI,ON,S,HNO, requires S 2= 11.18 per cent. A crystalline piwate melting at 160° was obtained from the mother liquor of the nitrate ; phenylethylcarbamylthiourea (from the corre- sponding thiocarbimide and ammonia) when treated in alcoholic solution with picric acid- gives no; picrate.144 DIXON AND HAWTHORNE : Phenylbenxylcarbamic Chloride and Thiourea. The hydrochloride, being somewhat impure, was dissolved in water and precipitated as nitvate, which crystallised from boiling water in long, stout needles changing colour at 145' and effervescing a t 154' : 0.348 gave 0.235 BaYO, ; S = 9.3.C,,H,,ON,S,HNO, requires S = 9.19 per cent. A crystalline picrafe was obtained melting a t 161"; on analysis : 0.2185 gave 30.8 C.C. moist nitrogen a t 17Oand 773 mm. N = 16.64. C21Hl,0,N,S requires N = 16.34 per cent, Benxpl Chlorocarbonnte and Phenylthiou.?*ea. Reference has already been made in an earlier part of this p p e r (p. 123) to the fact that alkyl chlorocarbonate derivatives of certain thioureas, when treated with alkali, do not behave in the same way as the corresponding compounds obtained from aryl chlorocarbonates. In so far as benzyl chlorocarbonate, although containiiig an arornatic group, is allied rather to the former class, it seemed probable that its compound with phenylthiourea would tend to pass readily into Benzyl- +-phenylt hiourea, NHPh*C( NH)-S C,H,, and an experiment was made in order to learn if this would be the case, As no special interest attached to the production of the additive compound of the two substances named above, the preparation was made under the influence of heat, which it was expected would decompose the additive compound as fast as formed, with elimination of carbon dioxide, but not of hydrogen chloride ; in effect, this proved to be the case.When phenylthiourea was heated on the water-bath with a slight excess of benzylchlorocarbonate in presence of benzene, carbon dioxide escaped with effervescence, and an oil was formed, which presently solidified ; the solid, after being washed, first with benzene and then with light petroleum, amounted to 97 per cent.of the yield calculated from the equation CSN,H,Ph + PhCH,.COCl= CO, + PhNH*C(NH)*S*CH,Ph,HCl. 3-52 grams of the product, dissolved in 500 C.C. of water, were treated with excess of normal alkali, the solid precipitate was then separated, and the filtrate neutralised with normal sulphuric acid, using phenolphthalein as indicator ; 10.5 C.C. of alkali were absorbed by the combined hydrochloric acid, instead of 10.9, as required by the above formula. The residual white powder, having an odour of benzyl mercaptan, crystallised from light petroleum in brilliant, pearly leaves, meiting at SO', which were insoluble in water, easily soluble in alcohol or inTHE ACTION OF ACID CHLORIDES ON THIOUREAS.145 hydrochloric acid ; this solution gave a crystalline picrute and a white mercuricldoride. The alcoholic solution was not affected by silver nitrate, but the mixture, when treated with ammonia and warmed, gave a yellow, flocculent precipitate, and the solution in alcoholic potash, when heated with a lead salt, was not blackened, but yielded instead a bright yellow precipitate. The substance was obviously Werner’s +-base, obtained by him from phenylthiourea and benzyl chloride (Trans., 1890, 57, 295); for this he gives the melting point 81-S2O, whilst our compound, once recrystallised, melted at SOo. With thiourea and benzyl chlorocarbonate similar results were obtained, and eventually Werner’s thiourea base, (Zoc.cit.) was isolated. N H,* C ( N H) S * C H,P h , Sunm c m ~ cbnd Conclusion. I n the following summary of the principal observations described or referred t o above, the statements have occasionally been put in somewhat general terms, although the number of cases tested may have been few. (i) Acetyl chloride or berizoyl chloride combines in molecular pro- portion with thiourea to form t h e hydrochloride of a “ b a s e ” or +-thiourea, in which the acyl group is joined to the rest of the molecule through the sulphur atom, as shown by the typical formula NH,*C(N H)*S*CO*CH,. By treatment of the hydrochloride with water, or by treatment of its alcoholic solution with one equivalent of sodium ethoxide, or with excebs of calcium carbonate, thiourea is regenerated ; if, however, the compound is melted, it loses hydrogen chloride only, the acyl group migrating t o the nitrogen atom so as t o produce acetyl- or benzoyl-thiourea. The hydrochloric acid may be displaced by picric acid, with formation of a sparingly soluble picrate of the base. (ii) Acetyl chloride or benzoyl chloride unites similarly with aryl monwubstituted thioureas, the products being quickly dissociated by water, as in the preceding cases ; it is possible, nevertheless, to obtain a picrate from the hydrochloride. On treating the hydrochloride in alcoholic solution with excess of calcium carbonate or with one equivalent of sodium ethoxide, the combined hydrogen chloride is eliminated, b u t (although the odour of thioscetic acid becomes per- ceptible) not with formation of the corresponding $-base, for example, ArNH*C*(NH)*S*COCH, ; instead, the my1 radicle migrates t o the nitrogen atom combined the aryl group, thus producing the isomeric ccu-disubstituted thiocarbamide, for example, PhAcN*CS-NH,. Under the action of heat or of dilute alkali, or, it may be, even by recrgstsl-146 SMITH AND ORTON : TRANSFORMATIONS O F lisation, the latter again changes, owing to further acyl migration, into an ab-disubstituted thiocarbamide. When melted, the above additive compounds lose hydrogen chloride, thereby changing directly inbo ah-disubstitutecl thiocsrbamides, AcNH*CS*NHAr. (iii) Acetyl chloride or benzoyl chloride unites additively with aryl- disubstituted thiocarbamides ; the products have not yet been examined in sufficient detail to justify a definite statement as t o how the acyl radicle is attached. (iv) Disubstituted cmbamic chlorides unite with thiourea, forming haloid salts of basic forms, XYN*CO*S.C(NH)*NH, ; the nitrates and picrates of such bases are sparingly soluble in water. Caustic alkali destroys the hydrochlorides without liberating a corresponding base, the group XYN*CO* undergoing ready hydrolysis into secondary amine and carbon dioxide. (v) If benzyl chlorocarbonate, PhCH,*O*COCI, is warmed with thiourea or with phenylthiourea, carbon dioxide escapes, and a com- pound is formed such as NH,*C(NH)*S*CH,Ph, in which the benzyl group is attached t o the sulphur atom. Aliphatic chlorocarbonates behave similarly. (vi) Organic acyl chlorides do not appear to be capable of uniting with a thiourea or thiocarbamide containing a distinctly acid radicle. The organic group of such a chloricle, however, sometimes expels from an acid-substituted thiocarbamide, and replaces, a radicle more highly electronegative than itself. CHEMICAL DEPARTMENT, QUEEN’S COLLEGE, CORK.

ISSN:0368-1645    

DOI:10.1039/CT9079100122

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

146 SMITH AND ORTON : TRANSFORMATIONS O F XIV.-T?.ansfor~~at.iolls of Highly Substituted Nitro- aminobenzenes. IL s- Tribromo- 1-nitroamino- benzene. By ALICE EMILY SMITH and KENNEDY JOSEPH PREVITE OSTON. IN earlier Fpapers (Trans., 1902, 81, 806 ; 1905, 87, 389) we described certain reactions which are exhibited by s-trichloro-1-nitro- aminobenzene when treated with sulphuric acid in acetic acid solution. It was shown that within certain limits of temperature and concentra- tion of the sulphuric acid, the nitroamine yielded some 30-35 per cent. of a s-trichlorophenyliminotrichlorobenzoquinone (hexachloro- quinoneanil). It was found possible, in bringing about this change, to avoid any displacement of chlorine by the nitro-group, a.nd consequentHIGHLY SUBSTITUTED NITROANINOBENZENES.11. 147 formation of a dichloronitroaniline. I n the case of the corresponding s-tribromo- 1 -nitroaminobenzene, on the other hand, it was observed that there was a far greatm tendency for the brbmine atom to leave the benzene nucleus, and in preliminary experiments such treatment as that described led mainly to the production of 2 : 6-dibromo-4-nitro- aniline. A number of experiments have, however, led to the discovery that 8-tribromonitroaminobenzene will under narrowly-defined conditions yield phenyliminobenzoquinones analogous t o those obtained from s-tri- chloronitroaminobenzene. This change is effected by solutions of sul- phuric acid in acetic acid containing a certain small percentage of water. The concentration of sulphuric acid, which has been found most suitable, is 0.6 of sulphuric acid to 1 of acetic acid; with such a solution the reaction is brought t o completion in one to two hours; higher concentrations of acid hasten the decomposition, but then the dibromonitroaniline is the main product.A t lower concentrations the decomposition is so slow that secondary reactions greatly decrease the yield of the quinoneanil. Using the most favonrable concentra- tions of sulphuric acid, it is only possible to obtain the quinoneanils if the temperature is kept, as low as possible, that is, at the freezing point of the solution ; atl higher temperatures, the formation of nitro- aniline again predominates. Addition of small quantities of water to the reacting mixture decreases the rate of the decomposition, but, a t the same time, there is a falling off in the formation of the nitro- aniline. About 4 per cent.of water is the most favourable concen- tration for the formation of the quinoneanil. Although it is possible to prevent the formation of the dibromo- nitroaniline, the elimination of a certain proportion of bromine could not be avoided. As a result, a mixture of quinoneanils is obtained, in which the s-tribromophenyliininodibromobenzoquinone largely pre- dominates over the s-tribromophenyliminotribromobenzoquinone. This elimination of bromine and consequent formation of penta- bromoquinoneanil is of considerable interest and throws some light on the mechanism of the formation of the quinoneanil from the nitro- arnine. The conversion of s- trichloronitroaminobenzene into a s-tri- c1 c 1 c1 chlorophenyliminotrichlorobenzoquinone, Cl/-\*N:/=\:O or \-/ \=/ c1 c1 c 1 c1 c1 Cl/-\*N:/=\: 0, necessitates the transference of a chlorine atom from one carbon atom to the neighbouring carbon atom in the benzene ring.The like holds for the formation of a hexabromo- \-/ \=/ c1 C1148 SMITH AND ORTON : TKANSFORiUA'L'lONS OF quinoneanil from the tribromonitroaminobenzene. But in the trans- formation of the bromo-compound, although the bromine is set free from its original point of attachment, only a certain proportion, and that the smaller, re-enters the benzene nucleus. I n the case of the trichloronitroamine, a complete re-entrance of the chlorine may take place ; nevertheless, since a t higher temperatures the presence of chlorine in small quantity can be detected among the products of the reaction, the difference between the tribromo- and trichloro-nitro- amines is rather one of degree.The other characters of the decomposition of the tribromonitro- aminobenzene generally resemble those of the trichloro-compound (Zoc. cit.) ; the quinoneanil represents some 30-35 per cent. of the nitro- amine, and a n equivalent amount of ammonia is produced. The remainder of the nitroamine is represented by s- tri bromobenzene- diazonium salts. The 'proportion of penta- and hexa-bromoquinone- anil appears t o vary considerably in different experiments, but the latter never exceeds a small percentage of the solid product of the reaction. The constitution of the pentabromoquinoneanil partly follows from the cleavage with sulphuric acid, when it yields s-tribromo- aniline and 2 : 6-dibromobenzoquinone. It is accordingly represented Br Rr by one of the formulze : Br/-\*N:/=\:O or \-/ \=/ Br Br Br BY 13r/-\.N:/e\:o, \-/ \=/ Br Br The halogen derivatives of 4-hydroxydiphenylamine are, with the exception of a tetrachlorohydroxydiphenylamine (prepared indirectly by Jacobson, Chew.Centy., 1898, ii, 36), unknown. Notwithstanding that hydroxydiphenylamine itself is prepared very easily by Calm's method from aniline and quinol, there is no record of attempts at chlorination and bromination. We hoped to obtain the bromohydroxy- diphenylamines, which are produced from the nitroamine, by direct bromination; to that end many experiments have been made, but it has been found that the bromination is no simple matter; such results as have been achieved will be shortly recorded.The study of the transformations of the nitroamines is being con- tinued.HIGHLY SUBSTITUTED NITROAMINOBENZENES. 11. 149 E XPER I MENTAL. Decomposition of s-Tribromo92itroumi~obense9ze. The products of the decomposition of s-tribromonitroaminobenzene (which mas prepared by the method previously recorded, Trans., 1902, 81, 805) in acetic acid solution by sulphuric acid are very dependent on the conditions, namely, temperature, and the amounts of water and sulphuric acid present, Generally speaking, the higher the temperature, and the larger the amount of sulphuric acid, the larger is the proportion of 2 : 6-dibromo- nitroaniline produced, and consequently of bromine eliminated, When the proportion (by weight) of the sulphuric acid to the acetic acid is above 1 : 1, the aniline is the main product ; with lower proportions of sulphuric acid, but at slightly elevated temperatures, 20' to 30°, a similar result follows.The 2 : 6-dibromo-4-nit~oaniZine mas obtained in characteristic yellow crystals melting a t 203O, and sparingly soluble in alcohol. 0.1654 gave 0.2092 AgEr. Br = 53.85. C,H,0,N,Br2 requires Br = 54.06 per cent. As the proportion of sulphuric acid is decreased to 0.6 : 1, and rising of the temperature above freezing point of the solution prevented, the rate of the decomposition becomes slower ; a t the same time the yield of the nitroaniline decreases, and, with the concentration of the sul- phuric acid just mentioned, is very small, a red sub;;tance (a mixture of bromoquinoneanils) being now the main solid product.Further lower- ing of the proportion of sulphuric acid is followed by such a decrease in the speed of the decomposition, that tbe nitroamine only disappears entirely after many hours' standing. The effect of addition of water to the mixture is mainly to decrease the rate of the decomposition, but at the same time with a given con- centration of sulphuric acid the production of dibromonitroaniline is less. A mixture of 30 grams of acetic acid and 18 grams of sulphuric acid, in which 1 gram of nitroamine was dissolved, contained no nitroamine after forty minutes, when so much water mas present as to produce a 2 per cent. solution. If, however, the concentration of the water was 4 per cent., the time required for complete decomposition was one hour and twenty minutes.I n the latter case, only a trace of dibromonitroaniline mas formed, whilct in the solution containing 2 per cent. of water some 5 per cent. of the nitroamine is converted into the nitroaniline. Prepamtion of the Red Solid (Mixture of Bromoquinoneanils).-In order to prepare the mixtiire of bromoquinoneanils as free from di-150 SMITH AND ORTON : TRANSFORMATIONS OF bromonitroaniline as possible, the following procedure was finally adopted. A solution of 50 C.C. of concentrated sulphuric acid (95 per cent.) in 50 C.C. acetic acid was slowly added to a solution of 5 grams of the nitroamine in 100 C.C. of acetic acid, the liquid being well stirred and cooled until a slight separation of ths solid solvent occurred.The first addition of the sulphuric acid led t o the development of a bluish-green colour, which finally changed to a deep olive-green. The liberation of bromine during the addition mas very obvious. The mixture was allowed to stand, generally for about one hour, and then poured on to ice, when a red solid separated ; this was collected and washed free from acid with water. Any unchanged nitroamine was removed by digestion with cold aqueous sodium carbonate ; the red solid was then dried over sulphuric acid in an evacuated desiccator. Examination of the Filtrate from the Bed Solid.-The acid filtrate was of a yellow coloiir and had a strong odour of bromine, The esti- mation of the amount of bromine showed that some 26 per cent.of one atomic preparation of the bromine in the nitroamine had been eliminated, The presence of s-tribromobenzenediazonium salt in the filtrate could be demonstrated by coupling, but was most clearly shown by conversion of the diazo-compound into s-tribromobenzene. To this end, an aliquot part of the filtrate was heated with one-third of its volume of alcohol. On cooling, s-tribromobenzene crystallised in long needles melting at 119-1 20°. Separation of the BromopuinonenniZs.-Although it is not difficult to obtain the pure pentabromoquinoneanil, albeit with considerable loss, from the red solid, the separation of both the penta- and hexa-bromo- quinoneanils is a matter of great difficulty, Repeated crystallisation from alcohol, acetic acid, or light petroleum, finally yielded a small quantity of the pentabromo-derivative of the correct melting point, 171".The mother liquors deposited a substance, melting indefinitely between 135' and 150°, which could not be further dealt with by simple crystallisation. The following method of treating the red solid has proved the most successful. The solid was extracted four or five times with small quantities of boiling light petroleum (b. p. 95'). The melting point of the undissolved residue gradually rose from 135-1 40", the original melting point, to 160". This residue mas then dissolved in a mixture of equal volumes of benzene and petroleum, from which solution the pentabromoquinoneanil separated in the pure state, melting a t 1 7 1 O .(Pentccbronto- 2 : 4 : 6 - T r i b r o m o ~ ~ ~ e n y l ~ a i ~ i o ~ i ~ ~ o ~ ~ a o b e ~ ~ ~ o p u i n o n eHIGHLY SUBSTITUTED NITROARlI~OnENZENES, 11. 151 Br Br quinoneccnil), Br/---\*N:/-z\:O (?)? crystallises in very dark red \-/ \=/ Br. Br needles with a bronze lustre ; these needles are sometimes aggregated in stellate clusters, a t other times they develop into well-formed prisms. It is readily soluble in chloroform, acetone, or benzene, and very sparingly so in acetic acid, alcohol, or petroleum. It is best crystal- lised from petroleum (b. p. 120') or from a mixture of benzene and petroleum. On analysis : 0.1509 gave 0.1390 GO, and 0.0150 H20, 0.2107 ,, 0.3442 AgBr. Br = 69.35. 0,3096 ?, 6.8 C.C. moist nitrogen at 8.8' and 748 mm. N = 3,625. CI2H,ONBr, requires C = 24.92 ; H = 0.7 ; N = 2.43 ; Br = 69.18 per Pentabromoquinoneanil can be hydrolysed by dissolving in excess of concentrated sulphuric acid or by boiling with a 30 per cent.solution of sulphuric acid in acetic acid. I n the latter case, a few minutes' boiling is necessary, On cautious addition of water, s-tribromo- aniline separates i n a nearly pure condition ; the 2 : 6-dibromobenzo- quinone can be extracted from the diluted mother liquor by means of chloroform or ether, and purified by crystallisation from dilute alcohol ; it crystallised in golden-yellow plates melting at 122*, and did not lower the melting point of a specimen of 2 : 6-dibromo- quinone. C=25.12; H=1*101. cent. 2 1 4 : 6 -Tribromophenyl-2' : 6'-dibronto-4-k.~drocc?/pheizylarnine, Br Br --To a solution of the pure pentabromoquinoneanil (m.p. 171') in acetone an equal weight of zinc dust was added, and glacial acetic acid was dropped in until the solution becanie colourless. After filtering, water was added, when a white solid, melting at 154", separated; from its hot solution in petroleum it crystallised in clusters of long, silky needles melting a t 155-156' : 0.1931 gave 0.3130 AgBr. Br = 68-96. C,,H,ONBr, requires Br == 68.94 per cent. The pentabromohydroxydiphenylamine is readily soluble in chloro- form, benzene, or alcohol, arid moderately so in glacial acetic acid; in petroleum it is but sparingly soluble, Dilute aqueous sodium hydroxide dissolves it freely. The hydroxydiphenylamiiie can be readily reconverted into the152 TRANSFORMATIONS OF NITROAMINOBENZENES. quinoneanil by oxidation with mercuric oxide in benzene solution, or by chromic acid in acetic acid solution.(Hexcchromo- quinoneanil) and 2 : 4 : 6- Tribrornop~enyZ~ribronzo-4-~~~~~0~?/;~- 2 : 4 : 6-~~ibromop~~en~lirnirzotribronzo~enxoq~inone Br Br hexabromoquinoneanil was contained in the petroleum extracts of the original red solid. On recrystnllising the material, which was ob- tained on evaporating this solution from petroleum, a substance was ohtained melting at 143-1 44'. Further recrystallisation failed to change the melting point. Analysis showed that it was a mixture of the penta- and hexa-bromoquinoneanils ; thus, bromine was found $0.6 1 and 70.74 per cent., whilst the pentabromo-derivative requires 69.18 and the hexabromo-derivative 73.04.A separation was only effected by reducing the qiiinoneanils to the corresponding Iiyclroxy- diyhen ylamines. This reduction WRS carried out in the manner above described, by zinc dust in acetone solution. The hydroxydiphenylsmincs were pre- cipitated 'by water from the acetone solution, and then extracted with small quantities of hot alcohol. A residue was left which melted a t 195' ; recrystallisation from chloroform or glacial acetic acid raised the melting point t o 207'. Analysis showed that this was the pure hexabromohydroxydiphenylamine : 0.184 gave 0.1491 CO, and 0.0163 H20. 0.1935 gave 0.3304 AgBr. Br = 72.66. C,,H,ONBr, requires C = 2 1 *86 ; H = 0.77 ; Br = 72.82 per cent, This hexabromohydroxydiphenylamine is sparingly soluble in all solvents ; it crystallises extremely well from chloroform in long, white, silky needles, and from glacial acetic acid in prisms.It dissolves freely in dilute aqueous sodium hydroxide. The alcoholic extracts of the mixture of It ydroxycliphenglamines yielded on evaporation a somewhat impure pentabromohyclroxy- diphenylamine ; it was oxidised to the corresponding quinoneanil which, after one recrystallisation from petroleum, melted a t 17 lo, the melting point of the pentabromoquinonesnil. HexabromoquinoneaniZ.-The hexabromohydroxydiphenylamine was converted into the corresponding quinoneanil in the following manner. 0.75 gram of the hydroxy-compound was suspended i n 25 C.C. of pure benzene and a slight excess of yellow mercuric oxide added. On warming the mixture, the hydroxydiphenylamine slowly dissolved.For complete oxidation several hours warming is required, On the other hand it is inadvisable to use excess of mercuric oxide, as c'= 22-1; I€=O-98.AFFINITP. CONSTANTS OF AMINO-ACIDS. 153 other changes are thereby induced. After filtering the solution, the quinoneanil is obtained in deep red, six-sided prisms on evaporation. This oxidation can also be conveniently carried out with chromic acid in acetic acid solution, Owing to the insolubility of the hydroxy- diphenylamine a large volume of solvent must be used. A slight excess of chromic acid dissolved in acetic acid is added to the solution of the hydroxydiphenylamine, the temperature being maintained at 20-30° ; a higher temperature is to be avoided. adding water, the quinoneanil crystallises in scarlet needles. Hexabromoquinoneanil is more readily soluble in all solvents than the pentabromo-derivative. It crystallises in prisms when its solution in cold benzene is slowly evaporated, and in small aggregates of needles from its solution in hot petroleum. It is remarkable that the latter crystals are pale red, whilst the prisms are a -deep port-wine colour. On The compound melts at 134-135O : 0.15 gave 0.256 AgBr. Br = 72.61. C,,H,ONBr, requires Br = 73.04 per cent. The authors wish to take this opportunity of expressing their thanks t o the British Association and to the Chemical Society for grants which have partly defrayed the cost of this research. UNIVERSITY COLLEGE OF NORTH WALES, BANGOR.

ISSN:0368-1645    

DOI:10.1039/CT9079100146

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

AFFINITP. CONSTANTS OF AMINO-ACIDS. 153 XV.-The Afinity Constants o f AminocarboxyZic and Aminosulphonic Acids as cletem-nined By the aid oj’ Met hy 1 - orange. By VICTOR HERBERT VELEY. Introductory. IN a former paper (Zeit. physikal. Chem., 1906, 57, 147) on the above subject it was established that the affinity factors of organic acids experimentally found by a tintometer method were in complete accordance with those deduced by Ostwnld and his co-workers by the electric conductivity method, in accordance with the well-known general equation : +(k) = u2/(1 - a) V a = p/p (1) The acids formerly investigated, namely the carboxylic, and certain VOL. XCI. M154 VELEP : THE AFFINITY CONSTANTS OF hydroxy-, nitro-, and chloro-derivatives of the aliphatic and aromatic series, conformed to two general types, expressible by the equations : 1.j Y = k X ( y = k x - b (ib) 11. logy=logk+x loga (ii) namely those of straight lines and logarithmic curves. I n the above equations y is the variable height of a column of a methyl-orange solution, x unit masses or volumes of acids added to a fixed similar column of the same methyl-orange solution, k the affinity factor. The constant b in equation (ib) depends on the conditions of each set of observations, and the constant x in equation (ii) is the number of unit masses of acid added less one. I n the present communication this simple line of investigation is extended more particularly to the aminocarboxylic acids, generally regarded as true amphoteric electro- lytes, and the aminosulphonic acids, a class of substances s0mewha.t neglected from the physico-chemical standpoint, although herein of more importance, as the indicator methyl-orange belongs to them.Method of Experiment .-This was precisely similar to that previously described, and consisted in adding successive portions of 0.1 C.C. of the several acid solutions to 20 c,c. of a N/40,000 methyl-orange solution contained in one tube of a tintometer, and varying the height of a column of the same solution contained in the other tube of the tinto- meter until the colour tints were equally matched. Improvements in the method of working might doubtless have been introduced, but as the investigation had been commenced somewhat hurriedly for the Sixth International Congress of Applied Chemistry a t Rome, it was thought best t o continue the work on the previous simple lines.Greater accuracy might have resulted from such improvements, such as a reduction of error from 5 to 3 per cent. or even less. However that may be, the results herein detailed conform in every way to t,hose obtained in the past work, and even though the experimental error may be regarded as excessive, yet it is not greater than those deduced from electric conductivity experiments, wherein observational errors of a first power magnitude become, by the process of calculation, of a second power magnitude. It will be understood that if 0.1 C.C. of a x/!N-solution of an acid is added to 20 C.C. of the standard methyl- orange solution, the concentration a t the first observation is xIZc)ON, and at the nth observation is x / - X The reciprocals of these numbers, designated V, are expressed in eqiiivalent acidic and not in molecular concentrations.Samples of Acids.-Some of the samples were purchased from well- known firms specially for the investigation; others were kindly supplied 200 7%AMINOCARBOXYLIC AND AMINOSuLPHONIC ACIDS, 155 from the laboratory collections of the University of Oxford and of Mag- dalen College, and by individual friends. I have to express my obliga- tions for kindness shown, and herein especially to the Directors of the Badieche Anilin- und Soda-Fabrik, who kindly presented me with a collection of aniline- and naphthylamine-sulphonic acids ; my only regret is that some of the acids were found, owing to their sparing solubility, to be not very suitable for the purpose of the investigation.Aminocccrboxylic Acids-Amphoteric Electrolytes. Within the last few years especial attention has been paid t o this class of substances; it is only necessary to refer to the work of Winkelblech (Zeit. plqsikal. Cli,ern., 1901, 36, 546), Bredig (Zeit. ElAtrochem., 1899, 6, 34), and Walker (Proc. Roy. Xoc., 1904,73, 155, and 1904,74, 271) on the amino-acids (aliphatic and aromatic), and of Johnson (Yroc. Roy. Soc., 1906, 78, 82 et sep.) and others on the methyl derivatives of the latter. (The special case of cacodylic acid, classed with the amphoteric electrolytes, will be considered separately.) I n the above-mentioned investigations both the acidic and basic con- stants have been determined by various methods ; in the present work only the former are studied, either as regards the acids themselves or their hydrochlorides.Aliphatic Aminocadoxylic Acids.-A rninoacotic acid (glycine), a sample of which was originally purchased from Kahlbauni and re- crystallised subsequently, gave no acid reaction, even with a solution of original concentration N/10 (compare Imbert and Astruc, Compt. rend9 1900, 130, 37) ; aminopropionic acid (alanine), originally purchased from Schuchardt, gave under the same conditions an acidity change too faint for accurate measurement ; hydroxyphenylaminopropionic acid (tyrosine) also gave no reaction with a concentration approximately iV/50, namely, at about the limit of its solubility in warm water, Thus, as regards their reaction with methyl-orange, the acidic and basic constants compensate one another.Hydrochlorides of the above Acids.-As preliminary experiments showed that these substances reacted with methyl-orange, mainly a3 hydrochloric acid, the aminocarboxylic acid only producing a slight positive or negative effect according t o its specific nature, results were obtained with hydrochloric acid itself for the purpose of comparison. Hydrochloyic Acid.-A standard solution, N/10, of this acid was prepared and its value ascertained by standard alkali ; this solution was diluted to concentrations N/400, N/300, and iV/200 respectively. The results obtained are given in Table I ; P is the equivalent con- centrations a t the first observation, x the units of 0.1 C.C. added (V/x being the correspondiag equivalent concentrations), and y the heights M 2156 VELEY: THE AFFINITY CONSTANTS OF of the variable tintometer column expressed in centimetres.(In successive tables the x column will be omitted and taken to be under- stood.) X. 1 2 3 4 5 6 7 8 9 10 11 12 Y= 8 x lo4. P y (found). y (calc.). - - - 3 ‘9 - 5.1 5.1 6-6 6.6 8.1 8.4 10.2 9-6 11.4 11.1 12.9 12’6 14.1 14.1 15.3 15% yi) TABLE I. Y=ci x 104. y (found). y (calc.). 8‘3 8 ‘3 10.5 10.7 12.9 13.1 15% 15 -5 18’0 17.9 20’9 20.3 - - Y= 4 x 104. ‘y (found). (y calc.). > - ;:g} - 5 -1 5-2 8 ’4 8-3 11’4 11.4 14-4 145 1 7 -7 17% 21 ’0 20.7 24’0 23 ‘8 26.7 26.9 - - - - If the results are set out graphically it appears that the first few observations (as bracketed) lie on a logarithmic curve, which does not pass through the origin of co-ordinates, but has the x axis as an asymptote (see I, Fig.1, for series 111). The remaining observa- tions lie on straight lines of general equation y = kx - b (cf. supra), the constants of which are for series I k= 1 5 , 6 = 2.4, for series I1 k = 2-4, 6 = 1.3, for series I11 k= 3.1, b = 4.1. The constants k are thus in the ratios 1.5 : 2.4 : 3.1, whereas if referred to their original concentrations and expressed in terms of the first of them, taken as correct the ratios are 1.5 : 2.25 : 3.0. On comparing the found values of y with those calculated from the general equation, substituting the second constants, it is evident that, with one or two exceptions, the differences are well within the 5 per cent. admitted limit.I n no case was the reaction pushed to its extreme limit, as it has been found previously that the red ion of methyl-orange formed by addition of excess of mineral acid could not be matched by a variable column of methyl-orange solution, which contains only the orange or orange-red ion. As regards the curved portion the equations to the logarithmic curves are, so far as they can be determined by obser- vations, few in number; for series I y=(O.23)2%, for series I1 y = (0.525)2~, for series 111 y = (0*65)2”. The curved portion corresponds to some induction period j it may be idle to speculate on the matter, but a possible cause is the presence of ammoniacal compounds in the water used which set up an opposing reaction to the methyl-orange. I n a former paper (Proc.Roy. Xoc., 1901, 69, 87) attention has been drawn to the persistent retention of some ammoniacal compound or compounds in distilled water, and more recently Burgess and Chapman (Trans., 1906, 89, 1414 e t sep.) have found the well-known induction period ofAMINOCARBOXYLIC AND AMINOSULPHONIC ACIDS. 157 hydrogen and chlorine to be caused, iizter alia, by the presence of ammonia or more probably complex ammoniacal compounds, albumin- oses or the like. However t h i s may be, since this induction period appeared in so many series of observations herein recorded, it is prob- ably due to some common cause. Glycine Hydrochloride.-A beautiful crystallinc specimen of this substance was presented to me by Mr. J. E. Marsh, F.R.S. ; some of Fro. 1. . 0 2 4 6 8 10 12 14 16 I6 Note as .to Plates.-The ordinates represent the heights in centimetres of the variable methyl-orange colnmn, the abscisase the unit masses, or volumes of the acids added ; the origin is shifted for the Graphs I1 and 111 (Fig. I), and for I1 (Fig.11), for the better comparison and to avoid overlapping. the crystals being of dimensions 14 x 8 mm. Mr. T. V. Barker, B.A., B.Sc., of the Mineralogical Department, Oxford, was kind enough to ascertain that the crystallographic axes and forms of the specimen, namely, orthorhomic, 1 : 1.1108 : 0.0309 ; forms, E P, oc p,, cc Poc , @ cfs , $P oc ; P ; hemihedral ; cleavage perfect, 1 leipa , were identical with those given by Schw:tbus in a somewhat obscure publication (Vienna, 1855), partly reproduced in Jahresber., 1854, 676.I58 VELEY: THE AFFINITY CONSTANTS OF Two solutions of N/150 and iV/200 coneentration respectively were made UP, which gave the results set out in Table 11.TABLE 11. y (found). y (calc.). y (found). y (calc.). Y= 4 x I 04. Y= 3 x 104. c L ,4 Y r 1 - 2 '8 6'3 4.1 4.0 10.3 9 9 6.3 6.8 13.5 15.5 9 '3 0 '6 16.8 17.1 12.3 12'4 19.8 20.7 15 '2 16.2 - - 18.0 18.0 - - 20 '4 20 *8 - - E} - - 6-3 2'6 E} - The results obtained are similar to those obtained from hydrochloric acid, the first few observations being upon a logarithmic curve, the remainder on a straight line ?=kx - b (compare I, Fig. 2, for series I). The values in the second and fourth columns are calculated by introducing constants 1%=3.6, b - 4 . 5 , and k=2*8, b = 7 * 2 . The constants i% are in the ratio 2.5 : 3.6, whereas if referred to original concentrations the ratio is 2.8 : 3.7, a difference within experimental error, The equations to the logarithmic curves are y=(O-3)P and y= (0.75)2%, so far as it is possible to ascertain them.Alumhe Hydrochloride.-This substance was prepared by dissolving aminopropionic acid in such a volume of concentrated hydrochloric acid that the latter contained a slight excess of that required for equimolecular combination. The solution was spontaneously evaporated, the crystalline residue washed with absolute alcohol, redissolved in water, and the solution spontaneously evaporated over sulphuric acid. The crystalline magma was dried on a porous tile, and the minute crystals, owing to their deliquescent nature, dissolved as quickly as possible in the required quantity of water.Only one set of experiments was conducted with this substance, as unfortunately within twenty-four hours of the preparation of an original solution a hypomycete had made a considerable growth therein.* * Though wholly foreign to the present inquiiy, yet it may be worthy of mention that these hydrochlorides of the amino-acids were found, from sad experience, to be most convenient media for the growth of such micro-organisms, doubtless as sup- plying carbon, amino-nitrogen, a i d chlorine ; so far as I m i aware the introductioq of tlrese snbstaiiccs in culture media has not been tried.ARIINOCARBOXYLIC AND AMINOSULPHONIC ACIDS. 159 TABLE 111. v= 4 x 104. I Y=4 x 104. h r- \ y (cnlc. ). - y (found).- 4.2 4.1 7.5 7‘4 y (found). y (cnlc.). 10-8 10.7 14’1 14.0 17’3 17’3 20’4 20.6 The figures in the second column are calculated from the equation y =kx - b, k- 3.3, b = 5.8 ; the results on the curved portion can be expressed by an equation 9 = (0*5)x2. FIG. 2. 14 12 10 8 6 4 2 0 0 2 4 6 8 I0 The behaviour of alanine hydrochloride is thus precisely similar to glycine hydrochloride. .Betchine Ifydmc?doyide.-A samplo of this substance was pur- chased from the Aktien-Gesellschaft f iir Anilin Fabrikation, Berlin, under the name of “Acidol,” being a preparation for the internal administration of hydrochloric acid in a convenient form for certain,160 VELEY : ?'HE AFFINITY CONSTANTS OF gastric complaints. The preparation was recrystallised from cold water by spontaneous evaporation and its chlorine contents determined by the Volhard method : Found, C1= 23.09.Solutions of original concentration N/400, i'V/300, and N/200, being equimoleculsr to those of hydrochloric acid (compare supra), were made up, and gave the results set out in Table IV. Calculated, C1= 23.1 per cent. TABLE IV. v= 8 x 104. 7- y (found). y (calc.) - ;::} - 2 *7 2'7 4'2 4.2 5.6 5.7 7-2 7'2 8 *7 8.7 10'2 10.2 V= 6 x lo4. - y (found). y (ca!c.). 0.6) - 1'2/ - 3.0 2 '9 4 '9 4.7 7.2 7.1 9.0 9.2 11.1 11 '3 13.2 13.4 Y= 4 x 104. y (found). y (calc.). 0 '6 - 3 '1 2.8 5.9 5.8 9.0 8.8 12.0 11.8 14'7 14.8 17.4 17.8 20'4 20.8 1.5) - The numbers in the second, fourth, and sixth columns are calculated from the straight line equation, the valws of k being taken as 1.5, 2.1, and 3, and those of b as 1*8,3*4, and 6.2 respectively (compare I, Fig.1, for series 111). T'yyosine Hydrochloride.-This substance was prepared according to the directions of Erlenmeyer and Lipp, and obtained in tufts of hard, glistening prisms, As it was further found, in accordance with the observations of these authors, that when excess of water is added to such crystals, tyrosine separates out, leaving a small portion, if any, of the salt dissolved in water, it was not possible to conduct any observa- tions with methyl-orange solution. General Conclusions.-In the following table the values of k for solutions of the same equivalent concentration are put together for the purpose of better comparison. TABLE V. V=8 x 104. V=6 x 10 V=4 x 10'. Y=3 x lo? - Hydrochloric acid .. . . . . 1 *5 2 '4 3 *1 Alanine hydrochloride . - - 3'3 - Betaine hydrochloride.. . 1 -5 2.1 3'0 - Glycine hydrochloride.. . - - 2.8 3 '6 Neglecting the result of alanine hydrochloride as possibly too high owing to the di6culty of obtaining this substance in a state of purity, the results of the remaining hydrochlorides of the amino-acids are very approximately equal to those of hydrochloric acid.ARIINOCARBOXFLI(T AND AMINOSULPHONIC ACIDS. 161 It would therefore appear that either (i) these hydrochlorides are hydrolysed completely, or nearly so, into the amino-acids and hydro- chloric acid, or (ii) the methyl-orange, as a disturbing factor, nearly completely displaces the former from the latter. The first hypothesis would seem a t first sight t o be in opposition to the experimental evidence of Bredig (Zoc.cit.) and Walker (Zoc. cit.), who found such hydrolysis to be partial and not complete. But the concentrations in the different methods of inquiry were widely different ; the most dilute solution used by the above observers equals V= 1024 (approximately lo”), whereas the most concentrated solution in my experiments equals V= 3 x lo4, or thirty times more dilute. Thus the discrepancy may only be apparent and not real; further electric conductivity measurements with such dilute solutions could only solve the question. The second hypothesis would involve the complete displacement of an aminosulphonic by an aminocarboxylic acid, although all results show that the former are more acidic and not more basic than the latter.Aspartic Acid.-A sample of this acid was purchased from Kahlbaurn and purified by recrystallisation. The following results were obtained : TABLE VI. Y= 3 x 104. Y= 4 x 104. Y=2 x 104. 1.05 2‘4 5 *1 2 -25 4‘2 7.8 3.9 6.3 11.1 5 5 5 8.1 14.7 The above results, though few in number as the reaction is soon complete, are similar in type to those of hydrochloric acid, in that the first few observations are in accordance with the logarithmic expression logy = k + xloga, the remainder with the straight line expression y = kx - b, the values for k being 1.6, 2-0, and 3.1 respectively. It appears remarkable that, firstly, aspartic acid, an amino- carboxylic acid, should behave as a strong mineral acid, and secondly, though the values of the initial period are less than those of succinic acid for the same concentration, yet in the corresponding straight line periods the value k = 1-7 of the former should be approximately three times greater than that of the latter, k = 0.6.Aspartic acid has been studied by P. Walden (Zeit. physikal. Chem., 1891, 8, 481) by the electric conductivity method, who found that as the values of V were increased in geometrical proportion, the values of162 VELEY: THE AFFINITY CONSTANTS OF k, instead of being constant, increased approximately in arithmetical proportion, and also that the value of k for solutions of the same con- centration were greater than those of succinic acid. This author obtained the following results. v. 32 6 1 128 258 512 1024 A?== rc ;, 102. Di flwcnc es.0-0067 - 0.00’79 1 2 0’0094 15 0.010D 15 0’0122 13 0’0137 15 The above results are expressible by a general formula, k = cc + blog V, or actually k = 0.0067 f (O.O014/log2) log;. Although it seems hardly possible to accept the hypothesis of Walden that this result is conditioned by the formation of an N H inner anhydride, CO,H*CH,*CH</,O , as this would, from the analogy of betaines, increase the basic function ; although also the abnormality of this acid might be due to the presence of an asymmetrical carbon atom associated with groupings which could not oompensate one another, yet it is a matter of special interest that the results obtained by the methyl-orange tintometer method proceed on parallel lines to those obtained by the electric conductivity telephone method.Cacodyli’c Acid, (CH,),AsO(OH).-This acid is here introduced as intermediate as regards its acidic function between the amino- carboxylio acids of the aliphatic and those of the aromatic series. During the past few years considerable discussion has taken place as to whether this acid can be truly classed among amphoteric electrolytes ; the literature h : ~ been collated by Johnson (Be?.., 1903, 37, 3625). It was shown by Imbert (Conzpt. TemZ., 1899, 129, 1244) that this acid is neutral towards alkalis with methyl-orange as an indicator, but it behaves as a monobasic acid with phenolphthalein a s indicator, an observation confirmed by Zawidski (Bey., 1904, 36, 3325). On the other hand, the valnes of k by the electric conductivity method obtained by different observers, although not concordant among themselves, nor even concordant with the same observer for different concentrations, yet so far agree in showing that the value is of an order corresponding to that of a true amphoteric electrolyte; this result is also confirmed by independent observations by the hydrolysis met hod.It seemed, therefore, of interest to study the behaviour of this acid by the methyl-orange method notwithstanding the above state- ment of Imbert, who, apparently, used the indicator according to the Usual practice of volumetric analysis,AMINOCARBOXYLIC AND AMINOSULPHOKIC ACIDS. 163 As the sample, purchased from Kahlbaum, was in the form of well- developed crystals, it was considered unnecessary t o purify it further. The following series of observations were made, of which two were conducted a t - one time with solutions from one stock, and the third after the interval of some weeks from another stock, TABLE VII.v = 2 x 103. Y=l x 103. Y= 5 x 103. 0.75 1.5 3 1-5 3 '3 6 2.25 4.8 9 -1 3.0 6 *3 11.9 3 * i 5 7'5 - 4 -5 - - It will be readily apparent that the results are all in accordance with the straight line formula y=kx, the values of k being 3, 1.55, and 0.75 respectively, namely, in the same ratio as their concentra- tions 4 : 2 : 1, and also by this method of experiment cacodylic acid has a higher acidity value than the aminocarboxylic acids of the aliphatic series, which gave no appreciable reaction with dilution v= 2 x lo3, but a lower value than the corresponding acids of the aromatic series (see below).Cacodylic acid would therefore be rightly classed among true amphoteric electrolytes. Amiiaocurhoxylic Acids (Aromatic). Aminobenxoic Acids.-As regards the reactions of these acids with methyl-orange, Imbert and Astruc (Zoc. cit.) observed that the 1 ; 2- and 1 : 3-acids are scarcely neutral, but the 1 : 4-acid is sensibly acid. All three isomerides were investigated; two of them the 1 : 3- and 1 : 4-acids were laboratory preparations, the third or 1 : 2-acid was purchased from Kahlbaum ; all were purified by recrystallisation. It was found that-these acids differed from the aminoacetic acids in possessing a distinct acid function, although the reaction soon came to a n end. The following results were obtained : TABLE Acid. Y= 1 x 104.3-1 1 : 2 6.2 c -- 1 : 3 J ;:; -- _- 1:4 I -- -.. VIII. Y= 2 x 104. 1.65 3'30 1'8 3 '6 5.4 2.2 4'6 6.5 - Y= 4 x 104. 0.85 1.7 2.53 0 '9 1'8 2'7 1 ' 2 2'4 3.6164 VELEY: THE AFFINITY CONSTANTS OF The above results, though few in number on account of the nature of the case, are all in accordance with the straight line formula y = kx, the values being the highest for the 1 : 4- and lowest for the 1 : 2-acid. The results are in general accordance, not only with the qualit'ative observations of Imbert and Astruc, but also with the conductivity measurements of Ostmald and Winkelblech, which have recently been discussed by Walker in connexion with his theory of amphoteric electrolytes. I t may be of interest t o compare the conductivity results of Winkelblech as set forth by Walker, and my results at the greatest dilutions only in each case : TABLE IX.Winkelblech. Vcley. Acid. KO x lo5 (Y=1024). K( V = 4 x lo4). 1:2 0.96 0.85 1:3 1 -07 0 '90 1 :4 1-17 1'2 The magnitudes are of a precisely similar order, the variations from a strict arithmetical ratio being such as might be expected by the application of methods so widely different. Oxanilk Acid.-This acid may conveniently be considered here ; the sample used was a laboratory preparation, which was purified by re- crystallisation. The folIowing results were obtained, and in the table the top figures in the third and fourth columns follow on from the bottom figure in the first and second columns respectively: I. Found. 1-5 2 -9 4.5 6'0 7.4 9'0 TABLE X. 11. Calc. 1.6 3-0 4.5 6.0 7 -5 9'0 v=4 x 104.111. Found. 10.8 12.3 18.8 15.6 17.7 19'8 IV. Calc. 10.5 12.0 13.5 15.0 16.5 18.0 The values given i n the second and fourth column are calculated from the straight line formula y = kx (k = 1.5) ; it will be observed that although at first the difference 9'- y is constant, namely, 1.5, yet towards the end there is a marked tendency for this difference to increase. Its behaviour is quite analogous to that of other acids, which likewise show an increase of electric conductivity factor (+)k with increase of dilution. Saccharin (BenzoicsuZphinimide).-Although this substance is notAMINOCARBOXYLIC: AND AMINOXULPHON~C ACIDS. 165 strictly an acid, but an imide, yet as it has been shown that it resembles acids in accelerating the decomposition of ammonium nitrite (Trans., 1903,83,747), being probably converted into the corresponding acid, SO,H*C,H;CO*NH,, on hydrolysis (a reaction which takes place on the digestive tract), it was thought worthy of interest to study its behaviour as containing a sulphonic and carboxylic grouping.The sample, originally purchased from Merck, was purified by recrystallisation, and the results obtained were as follows : TABLE XI. Y= 8 x lo-'. v=4 x 104. A A r \ /- 3 y (found). y (calc). y (found). y (calc.). 1.2 1.7 2.6 2.7 2.7 4.0 5'4 7% 10'8 2.7 4.1 5.4 7.6 10 -8 5.4 10 9 Y > I > Y > 5 '4 10'8 Y Y > > > * I n both cases the values of y a r e calculated from the logarithmic equation logy=logk+sloga, in which the values of k are 1.9 and 2.7, and of a are 1-41 and 2.0 respectively.It would appear from tho above results that saccharin on hydrolysis gives an acid with a sulphonic and not a carboxylic grouping, since towards methyl-orange it behaves when in solubion as an acid of high acidic function, resembling formic and oxalic acids. Aminoswlp?honic Acids. Hitherto the affinity constants of these substances has been deter- mined mainly by the electric conductivity method, partly by Ostwald (Zeit. physikal. Chevn., 1889, 3 , 406 et seq.), and more fully by Ebersbach (ibid., 1893, 11, 608), and it has been shown generally that the magnitudes of these constants are of a higher order than the aminocarboxylic acids ; the aminosulphonic acids are not therefore usually classed among the true amphoteric electrolytes, from which they differ in other important respects.Anilinemonosul~honic A cids.-Two out of the three isomeric modi- fications were investigated, namely, the 1 : 4 or sulphanilic acici (two specimens, one a laboratory sample, and the other purchased from Kahlbaum), both of which were purified by recrystallisation, and the 1 : 3 or metanilic acid, supplied by the Badische Anilin- und Soda- Fabrik, also recrystallised. Metanilic Acid.-The following results were obtained :166 VELEP: THE AFFINITY ONSTANTS OF v= 4 x 104. Y= 2 x l O J * 1.95 3.8 3.8 8.0 5 . i 12.0 TABLE XII. y=4 x 104. Y=2 x 10.' 7'4 16'3 9 .o 20 '8 10.8 I The results in both cases are in accordance with the straight line expression y = k x , the values of Ic being 1.85 and 4 respectively, the ratio of the numbers being that of their concentrations within the 5 per cent.error. SuZpha?dic Acid. obtained from one only of them are given : As the two samples, alluded to above, gave identical results, those TABLE XIII. Y= s 104, y (foluld). y (cnlc.). / A 7 0% 1 -05 1.6 1.6 2.3 2.2 3.3 3.2 4 '9 4'6 6.7 6.7 9'3 9.6 13.8 13.9 Y= 4 x 104. y (foLll~d). ?J (calc.). A f 7 1.2 1-65 3.2 3.3 6.6 6'6 13.2 13'2 > 7 7 ) The results given in the second and fourth columns are calculated from the logarithmic expression logy = logk + xloga, the values for k being taken as 1.05 and 1.65 and of a 1.45 and 2.0 respectively. It appears remarkable that of these isomerides one should conform to the straight line and the other to the logarithmic expression; the results for t h s same concentration are set out graphically in curve I1 (figs.1 and 2). Ostwald (Zoc. cit.) found that both the 1 : 3- and 1 : 4-acids gave regular residts, although the value of Ic for the former was about three times greater than for the latter (actually 0.0581 : 0.0181). However this may be, it mill bs shown in the sequel that such a difference in behaviour of isomeric aminosulphouic acids is not unique. Anilinedisulphonic Acids.-Only one of the possible isomeric modifi- cations was investigated, namely, the 1 : 2 : 4-acid) supplied by the Badische Anilin- und Suda-Fabrik. The sample was purified by dissolving in hot water, filtering through animal charcoal, crystallising, and drying the crystals on a porous tile; in this way a white specimen was obtained.As a sufficiently marked reaction was not produced with N/100 original solution (V being thereby 1 x l O 4 ) , a solution which gave Y= 0.75 x lo4 was used, and the following results mere obtained :AMINOCARR OXTLIC AND AMINOSULPHONIC ACIDS. 167 TABLE XIV. y (fOlUl~1). ?J (calc.). 1.5 1 -5 3'2 3.0 6.5 6.0 11.9 12'0 The values given in the second column are calculated from the formula logy=logr%+xlogtc (r%=1-5, a=2). It is evident that the introduction of a second S(13H grouping into the 1 : 4-anilinesulphonic acid decreases rather than increases the affinity constant or acidic function. As the same conclusion is arrived at, not only by electric conductivity results, but also by my results to be described in the sequel, it will not be necessary to consider further a matter so contrary to previously formed conceptions.T h e Ncq&hyZaminesulpA onic Acids.--I was advised by Prof. Bernthsen, the Director of the Laboratory of the Badische Anilin- imd Soda-Fabrik, that although the preparations mere moderately pure, yet for the purpose of physico-chernic-il investigations they should be purified by recrystallisation. Unless otherwise stated these preparations mere purified by one or more recrystallisations from water. a - 21rc~pJ~tl~yZanzir~e~~o~ao,~u Iphonic A cicls. The 1 : Z-Acid.-As it was found that this sample contained some of its sodium salt, being doubtless derived from the corresponding salt of the 1 :$-acid from which it was prepared, and did not give homogeneous crystals by the process above described, the original material was digested with dilute hydrochloric acid for two days, the coloured liquid drained off, and the residue washed with cold water until the washings gave no precipitate of silver chloride on addition of solution of the nitrate.The residue was then treated by the usual process, and, after a considerable but unavoidable waste of material, pale pink crystals were obtained, which appeared quite homogeneous when examined under the microscope. The following results were obtained :168 VELEY: THE AFFTNITY CONSTANTS OF TABLE XV. Y= 8 x lo4. v= 4 x 104. ------7 ?J (found). y (talc.). y (found). y (calc.). 0.75 1.8 j - 1 -5 1 - 1.2 1 5 4 5 .j 5.1 4 3 8‘4 8.0 9.3 9 ‘4 - - 14.4 14.0 - - 18.0 18.6 3 .O 3-0 2.7 J The above results are less satisfactory than those obtained in any other set of observations, and it is thought possible that some secondary change might intervene at the outset as the tint produced, on addition of the successive portions of the acid t o the methyl-orange solution, only assumed its final shade after standing for some minutes, and not immediately as in other cases.But notwithstanding the imperEections, from whatever cause they may arise, the results are sufficient to show that this acid behaves as a strong acid (hydrochloric acid, for example), in that the first few results conform approximately to the logarithmic expression and the remainder t o the straight line expression y = kx - b. (The results given in the second and fourth columns are calculated from constants k = 2.5 and 4.6, b = 4.5 and 13.6.) The results are in accordance with those obtained by Ebersbach by the conductivity method, who found values for k varying from 2.23 (V= 64) to 1.09 ( Y = 2045) ; whether the former or the latter of these numbers or the mean thereof be taken, yet the value is five to fifty times greater than that found for any other naphthylaminesulphonic acid, and is of the order of magnitude corresponding to that of a nitro- aromatic acid, 1’he 1 : 4-acid was not sufficiently soluble in water for the purpose of this investigation.Z’?t,e 1 : 5-acid gave a pale pink solution with slight ++ blue fluorescence when dissolved in water, but owing to its sparing solubility i t was difficult to work with, and only one set of observations was made : The point will be further discussed in the sequel.* Wherever here, or i n the sequel, the word “slight” is applied to the fluorescence, it will be taken t o mean the appFcarmce of the solutions under the conditions of ordinary daylight; when the beam of an electric arc is projected through such solutions the eflect produced is quite magnificent.AMINOCARBOXYLIC AND AMINOSULPHONIC ACIDS. 169 TABLE XVI. V= 4 x lo4. Y= 104. I y (foulld). y (cslc.). 1 . 0 1.12 3 '4 2-25 4.5 4.5 The results in the second column are calculated from the expression The 1 : 6-mid dissolved in water to give a pale pink solution ; the log y = log 1.12 + x log 2. following results were obtained : TABLE XVII. Y= 8 s lo4. ~ = 4 x 104. v=2 x 104. v- /-- 7- y (found). y (calc.). y (found). y (calc.). y (foiiiid).y (calc.). 0.63 0.7 1.2 1.42 2 *8 2.8 1 '27 1 *4 2.8 2.85 6.0 5.6 2-65 2 *a 5'7 5 *7 11.1 11.2 5 *1 5.6 11 '4 11.4 19 -2 22 -4 The values in the second, fourth, and sixth columns are calculated from the expression logy = logk + xlog2 (k = 0.7, 1.42, and 2.8) ; the last observation in the 2 x lo4 series is rather low, but it was evident on repetition that the possible reaction was nearly complete. The 1 :7-acid dissolved in water to give a pale pink solution with a faint blue fluorescence ; the following results were obtained : TABLE XVIII. Y=8 x lo4. Y=4 x 104. --\ 7- y (found). y (calc.). y (foullcl). y (calc.). 0.6 0.6 0 ' 9 1.25 1 2 1.2 2.4 2.5 2-4 2.4 4 -95 5.0 - 9.9 10.0 - The values in the second and fourth columns are calculated as above (k = 0.6 and 1-25 respectively), and it is evident from the figures given that the 1 : 7-acid is slightly weaker than the 1 : 6-acid.Ebersbach's results showed that the 1 : 7-acid was slightly stronger than the 1 : 6-acid (k= 0.0227 and 0,0195 respectively), The 1 : &acid, although obtained in a perfectly homogeneous crystal, showed no acid function whatever, even when added in very consider- able excess to the methyl-orange solution. This result will be further discussed, but it is in accordance with Ebersbach's result, who obtained VOL. XCI. N130 VELEY: THE AFFlNITY COKSTANTS OF a value of k = 0.001 in round figures, one-twentieth of the values of the 1 : 6- or 1 : 7-acids. P-i~TccpiithyZamineszr Zphonic Acids, The 2 : I-mid was obtained in pale pink prismatic needles; its solutions gave the following results : TABLE iT= s x 1 0 4 .y (found). y (calc.). 0.3 0.5 0.9 1.0 2'25 2.0 4'2 4.0 8 -1 8.0 /-'-- XIX. Y= 4 x 104. -- 1.05 1 *15 2 *1 2 -3 4.8 4'6 9'6 9.2 18% 18.4 y (found). y (calc.). The values in the second and fourth columns are calculated as above ( k = 0.5 and' 1 *15, a = 2 respectively) ; the K constants are not widely different from those of the 1 : ?'-acid, although the reaction proceeds further. The electric conductivity constant has apparently not been determined. The 2 : 5-acid was obtained as a fine crystalline powder ; its solutions gave the following results : TABLE XX. y (foniid). 7J (calc.). y (found). y (cdc.). Y=S x 104. v= 4 x 104. ---- /-- 0.9 O*i5 1 *5 1.45 1.5 1 *5 3.0 2.9 2-85 3.0 6.0 5.8 - - 11'4 11'6 The values for k are taken as 0.75 and 1.45 respectively ; it mill be observed that though they are both higher than those of the 2 : 1-acid, yet the possible reaction sooner came to an end.The 2 : 6-acid was not sufficiently soluble for the purpose of investi- gation. The 2 :'l-cccid was obtained in pale pink needles; owing to its sparing solubility only one set of observations was made and the solu- tion kept warm for the purpose. The results are given below : TABLE XXI. i/-= 4 x 104. y (fouacl). y (calc.). 1 *2 1 - 1 6 2'4 2.3 4.5 4-6AMINOCARROXPLZC AND AhftNOSULPHONIC ACIDS. 171 The value of k=1*15 is identical with that of the 2 :l-acid at the same concentration, but all reaction sooner comes to a n end. Y'he 2 : Y-chcid was not sufliciently soluble for quantitative determina- tions, but it was proved that even on addition of a considerable quantity of a supersaturated solution to the niethyl-orange no change mag produced; the acid therefore resembles the 1 : 8-acid in showing no acidic function whatever.Dimeth~Z-2-na~l~thyZc~naine-8-su~~~o~ic Acid.--I am greatly indebted to Dr. C. Smith for a sample (about 1 gram) of the above acid pre- pared and described by him (Trans., 1906, 89, 1508); as sent it was in the form of crystalline (ncicular needles) powder. When dissolved in water at 25", so as to give a X / l O solution, the liquid was of a pale yellow colour, but more dilute solutions displayed a beautiful pale blue fluorewence, so that their appearance somewhat resembled a very dilute solution of copper sulphate.A8 the iVjl0 solution gave a n immediate acid reaction with t h e met'hyl-orange solution it mas further diluted, and the following results obtained : TABLE XXII. V= 8 x lo4. V S G x 104. Y= 4 x 104. v-2 x l o ? - 7- -7 - y (found). y (enlc.). y (found). y (cnle). y(founcl). y (calc.). y(fmiid). y (calc.,, 0 -7 0 -65 0.9 0.9 1 *2 1-35 2.7 2.75 1 '2 1 *3 1 '8 1'8 2.7 2.7 6'0 5-5 - - 3 -7 3.6 5'4 5 '4 10'8 11.0 Although the above acid differs from the other naphthylarnine- mono- and di-sulphonic acids (see below), mhich contain a n S0,H grouping in the 8-position, i n that it shows a n acid reaction with methyl-orange, and although also the values of k in the expression logy = logk + dog2 ( k = 0.65, 0.9, 1.35, 2.75) are between the values found for the 2 : 1- and 2 : 5-naphthylaminesulphonic acids, yet all possible reaction sooner comes to an end.The results for the most dilute solution (8 x lo4) are almost too small for accurate measure- ment; they have been quoted, not as of much import, but as of concordant arithmetical ratio with the remaining series. However, the results are in perfect concordance with those obtained by the electric conductivity method in the case of the benzenoid aminosulphonic acids, which have shown that the substitution of hydrogen by methyl in the NH, grouping increases the value of k. The following illustrative examples are taken from the papers of Ostwald and Ebersbach (Zoc. cit.) ; NH,*C6H,*S0,H (1 : 4) 0.0586 NHz4CC,;H',-SO3H (1 : 3) 0.0186 NHMe*C,H,*SO,H ,t 0'0666 NMe,*U,H,*SO,H ,, 0.037 k. k, N 2172 VELEY : THE AFFINITY CONSTANTS OF Opportunity was taken to determine certain other physical data of the 2 : 8-dimethylaminosulphonic acid, namely the density of the N/10 solution, the solubility in water, and the degree of fluorescence.The following results were obtained: D;; (solution a t or about its maximum saturation) = 1.0073 ; DZ = 1,0058 ; the weighings were corrected to a vacuum, and the thermometer corrected according to the Reichsanstalt methods, Solubility S (grams in 100 grams water at 25") =3*47. The blue fluorescence described by Dr. C. Smith is very remark- able ; in ordinary daylight, under certain conditions, it is visible with a solution of concentration of the order of N / 2 x 105, or nearly one part in a million.When a solution of the acid is allowed to evaporate spontaneously, well-formed transparent crystals separate, but at present they have not been obtained of sufficient dimensions for accurate crystallographic measurement. a-iVcqAtJbg Zaminedisu Zphonic Acids. Acids derived from tJLe 1 : 4-monosu~phonk Acid.-TAe 1 : 4 : 2-acid, obtained as a white, crystalline powder, dissolved in water giving a pale pink solution with a purple-blue fluorescence. Two series of observations were made : TAELE XXIII, v=i x 104. Y=O.G Y 104. 0.9 2.1 1.8 4.2 2 -7 6.1 3% 8.4 4.5 10.5 y Z 1 104. v=065 x 104. 5.4 12.6 6'3 14'7 7-2 16.5 8-1 - This disulphonic acid is remarkable in that, firstly, it was necessary to use more concentrated solutions to obtain observations, and, secondly, of all the mono - and di-naphthylaminesulphonic acids examined this is distinguished from the rest in giving results which conform to the straight line expression y =kx (k=0.9 and 2.1) ; in this respect it resembles metanilic acid.The introduction of a second sulphonic grouping in this as in other cases diminishes rather t)han increases the acidic function. The 1 : 4 : 6-acid was a white, crystalline powder, giving a nearly colourless solution with a pale blue fluorescence. The following results were obtained :ANINOCBRBOYY LIC AND AMINOSULPHONXC ACIDS. 17 3 TABLE XXIV. Y= 4 x 104. Y= 2 x 104. v=i.5 x 104. A - c > - y (found). y (calc.). y (found). y (calc.). y (found). y (calc.). 0.6 0% 1.2 1 *35 1.9 3 '9 1.5 1 *2 2'7 2.7 4.2 3.8 2.4 2'4 5 -4 5.4 7.5 7.6 4.8 4 *3 10.9 10.8 - - The results are in accordance with the logarithmic expression ?'he 1 : 4 : 7-acid, obtained as a slightly deliquescent white powder, The results were as follows : (k = 0.6, 1.35, 1.9, C& = 2).became slightly discoloured when dried at SO". v=4 x 104. v=2 x 104. A c A 7 .-- \ y (found). y (calc.). y (found). y (calo.). 0.6 0-6 1 -2 1 *3 1.2 1 -2 2 -7 2.6 2 *1 2 4 5.4 5.2 The values found are practically identical with those of the 1 : 4 : 6- acid, although the reaction sooner comes to an end. The 1 : 4 : 8-acid was obtained in yellowish-pink tabular crystals giving a yellow solution with faint fluorescence. The acid reaction, even with original solution N/10, was almost inappreciable, and thus in terms of the other acids its effect may be considered nil.The 1 : 5 : 7(?)-acid (Badische Anilin- und Soda- Fabrik, D.R.-P. 69555) is prepared by sulphonating aceto-a-naphthalide or its 1 : 5 - sulphonic acid and hydrolysing the acetyl compound with dilute sulphuric acid. The 7-position of the sulphonic-grouping appears t o be doubtful. The sample sent was purified by allowing a cold- water solution to evaporate spontaneously ; pale yellow needles separated, which rapidly effloresced. A solution of original concentration Nj25 gave no acid reaction with methyl-orange even on addition of excess. Therefore this acid behaves as acids which contain a sulphonic grouping in the 8-position. But so long as the constitution of the acid remains a mcitter of doubt, it does not appear desirable t o draw any conclusion.174 VELEY : THE AFYINITY CONSTANTS OF The P-hTap11t11yZami32edisu123joonic Acids.T h e 2 : 3 : 6-acid was obtained partly as colourless, glassy plates, which rapidly effloresced, partly as a pale pink amorphous powder ; by a process of rapid evaporation it was obtained in the latter form only. The acid probably, therefore, occurs in n labile crystalline and a stable, amorphous modification, but the conditions under which one or the other is formed have not as yet been accurately ascertained. The solutions showed a purple-blue A uorescence. Two series of observa- tions were made with the following results : TABLE XXVI. y (foluld). y (calc.). 2/ (foluld). y (calc. ). 0.6 0.65 1.2 1 ‘25 1-5 1.3 2‘6 2 ’5 2’4 2% 5.1 5.0 - 9-9 10.0 v=4 x 104. v=2 x 104. A r- , .I The values for k are not widely different from those obtained for the 1 : 4 : 7-acid. The 2 : 6 : &-mid gave no reaction with an original solution N/50, even when added in excess ; hence relatively its effect may be regarded as nil. General Conclusions regarding the Nap~~tl~ylanaiiiesul~honic Acids. On reviewing the results obtained with these acids, two general facts come into prominence : namely (1) the positions 2 and to a less extent 7 afford cases of steric “furtherance,”” and (2) the position 8 affords a case of steric ‘‘ hindrance.” As regards the steric hindrance effected by the 8-position, my observations are quite in accordance with those of Hewitt and Mitchell, as also of C. Smith (Zoc. cit.), in their studies on the reaction of various naphthalene derivatives with diazonium salts.On the other hand, as regards the steric furtherance of the 2-position my observations are in accordance with the results of Ebersbach. A t present there do not appear to be many data as to the effect produced by the 7-position, relative to the positions 1 and 2. * As the phrase ‘< steric hiiidiance” has now come iiito chemical literature, I have ventured t o use the oltl Saxon word “ furtlierance ” as its opposite. It appears that the iionn has been user1 in this sense sirice 1440 ( I‘o7.k M y s t c ~ y Plny), ant1 thc verb so fa1 back as 888 (BZfrerE C‘hrm.). 1’eilial)s I iiiny raise n p l c : ~ for the use of Saxon ~vorc~s, rather than those derived from Grcc.1~ or Latin, sepafirtely, or even worse, con j oi 11 t 1 y.AMINOCABUOXYLIC: AND AMINOSULPIIOKIC ACIDS. 175 (i) The method of determining the affinity constants of acids by means of a dilute methyl-oiaange solution and a tintometer, formerly applied to the carboxylic acids and certain chloro- and hydroxy- derivatives, has been extended to the amino-carboxylic and sulphonic acids. It is shown that the same general mathematical expressions hold good, namely, those of straight lines, or logarithmic curves. (ii) Acids which show irregularities in the Ostwald electric con- ductivity expression +(k) = az/(l - a)V show similar irregularities in the methyl-orange method. (iii) The aliphatic aminocarboxylic acids act as neutral substances, but their hydrochlorides as hydrochloric acid only, hydrolysis being nearly complete a t the degree of dilution used. (iv) The special cases of aspartic and cacodylic acids have been investigated, (v) The aminobenzoic acids show a distinct acid function, and the factors obtained are in a similar arit.hmetica1 ratio to those deduced by Winkelblech a t a different degree of dilution of t h e electric condnc- tivity method. (vi) The two aminobenzenemonosulphonic acids studied, namely, sulphanilic (1 : 4) and metniiilic (1 : 3) acids, are remarkable in that the latter conforms to the straight line, but the former to the logarithmic expression. The introduction of a second sulphonic- grouping reduces rather than increases the acid function, (vii) The study of the naphthylaminemono- and di-sulphonic acids affords examples of steric furtherance as regards the positions 2 and 7 and of steric hindrance as regards the position 8. Lastly, I desire to express my thanks to Prof. Win. Esson for assistance in the mathematical portion, and again to my colleagues a t home and abroad for having kindly supplied me with such a wealth of material, without which this investigation could not have been completed.

ISSN:0368-1645    

DOI:10.1039/CT9079100153

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

176 DE MOUILPIED AND RULE : TETRAKETOPIPERAZINE. XVL- T~traketop~~erazi,2e. By ALFRED THEOPHILUS DE MOUILPIED AND ALEXANDER RULE. THE formation of ring compounds by the action of sodium alkyloxides on various phenylglycinoacetic esters has been investigated by one of us (Ber., 1900, 33, 2467; Trans., 1905, 87, 435). The ease with which alcohol is eliminated in these cases has led us to apply the reaction to esters of the type of ethyl oxamate, in the hope that by the elimination of a molecule of alcohol between an *OR group and an *NH, group, ring compounds containing an imino-group might be produced. I n general, the reaction might be expected to be as follows : ...___._... . Ethyl oxamate would by such a reaction give rise to the three- membered cyclic compound, oxalimide, Yo>NH, the existence of which lias not yet been clearly established. The only reference to this compound is in a paper by Ost and Mente (Bey., 1886, 19, 3228).The authors describe the preparation of oxalimide from oxamic acid by the action of phosphorus pentachloride, the yield being very small. It is described as crystallising in colourless, well developed monoclinic prisms. No reference is made to the melting point, and the results of analysis given apply equally well to a substance with twice the molecular weight, such as tetraketopiperazine. On boiling with water, the substance decomposed into oxarnide and oxalic acid, and Ost and Mente thought it might be dioxaldiamide, co (?o”H*?o but they rejected this hypothesis on the ground that such CO*NH*CO’ a compound ought on hydrolysis to yield equal molecules of oxamide and oxalic acid, which thoy found not to be the case.This, however, is not to be expected, as any oxamide formed by the hydrolysis of the parent substance would, in its turn, be equally liable to saponification t o oxamic and oxalic acids. We found that during hydrolysis of t jtraketopiperaxine, ammonia WAS evolved, and that the relative proportions of the products depended on the time of reaction and on the concentration of the hydrolyser. Ost and Mente supposed that the simple oxalimide was obtained by them and that this reacted with water t o form oxalic acid andDE MOUILPIED AND RULE : TETRAKETOPIPERAZINE. 177 ammonia ; the latter then reacted with more oxalimide to form oxamide. It seems improbable that a compound of the configuration of oxalimide would have the stability ascribed to it by these authors.The present paper contains an account of the preparation and properties of tetraketopiperazine, and there seems to be but little doubt that this is the substance which they obtained and which is described in text- books as oxalimide. Further, their work has recently been re- peated," and no trace of either oxalimide or tetraketopiperazine could be detected. We firstlapplied our method to methyl succinamate ; this, on trent- ment with sodium alkyloxide in benzene solution, lost a molecule of nlqohol and gave succinimide, although in no great quantity. I n the case of ethyl malonamate, no ring forination took place as far as the main reaction is concerned, but the preferential saponifica- tion of the carboxyalkyl group in regard to the amino-group was brought about, Malonsmic acid was not, however, isolated, but a n acid resulting from the loss of one molecule of water fyoni two molecules of the mnlonamic acid : 7 O.CH,*CO-NH, Co*NH2 - H,O -+ 2CH2<C0,H NH*CO*CH,*CO,H ' The use of theoretical amounts of sodium alkyloxides in dry benzene solutions seems to be a method of general application €or the preferential saponification of carboxyalkyl groups occurring in the same compound with acid amide groups. I n the ordinary way, a *CO*NH, group is readily saponified by alkali and always more easily than an accompanying *CO,R group.Thus, in the case of ethyl oxamate, treatment with caustic soda causes an evolution of ainnionia in the cold.Using the theoretical amount of sodium ethoxide in benzene solution, a good yield of sodium oxamate is obtained. We believe this method mill be found to be of general application. I n addition to oxamic acid, the latter reaction yields, after treatment with water, filtration and acidification with hydrochloric acid, a substance which analysis showed to have the formula C,H,O,N, and a molecular weight of 142. This is the dioxaldiamide of Ost and Nente, or tetra- ketopiperazine. A better jield is obtained if ethyl oxamate is treated directly with the theoretical amount of sodium ethoxide in absence of * The work has been carried out in these laboratories by Dr. A. W. Titherley and Dr. A. A. Hall in connexion with the attempted synthesis of oxalimide, and they inform us that their results were entirely negative.178 DE MOUILPIED AND RULE : TETllAI(ETOP1I'ERAZINE.benzene. of oxamide with ethyl oxalato in presence of sodium ethoxide : We have also obtained the substance by the condensation co*co PO.NH~-H-.---C,H~o-~OF! CO*NH:!H C,H,O~OC --f NH<Co.CO>NH. Light is thrown on the configuration of this compound by the fact that it forms a monohydrazone, mono- and di-sodium salts, and a di-silver salt ; we were not able t.0 prepare a pure mono-silver salt. Cold sodium hydrogen carbonate acts on the substance with effervescence to form a white mono-salt ; the di-salt is obtained by the use of sodium hydroxide, but the action in this case is complicated by the fact that hydrolysis is concurrent, and we could only obtain the pure salt by using the alkali in the form of the theoretical amount of sodium alkyloxide, all moisture being carefully excluded.These re- actions point to the probability of the existence of one hyclroxyl group in the molecule reacting directly with sodium hydrogen carbonate t o form a mono-sodium salt, and to-the possible presence of a second hydroxyl group by tautoineric rearrangement between the COO and NH* groups under the influence of stronger alkali. The substance has thus probably the following constitution : This formula shows one of the ketonic groups to be different in nature from the others, and this may account for the- formation of a monohydrazone. Tho yield of sodiuin salt obtained in the preparation of the substance shows the salt to be dibasic.We purpose investigat- ing the reduction products of this substance, the action of alkyl iodides on the sodium and silver salts, and the products of the interaction which takes place with aniline. E x PE R IRI E N T A L. Xucciitimicle from Nethyl Xucci?zni,zccte.-U.6a gram of sodium wire (I atom) was placed in 100 C.C. of dry benzene, and dissolved in rather more than 1.1 gram (1 inol.) of methyl alcohol by warming on the water-bath. 0.4 gram of methyl succinaniste (1 mol.) was added, and the mixture heated on the water-bath for two hours and allowed to cool. Water was then added and the aqueous part separated from the benzene, which was extiacted several times with water. The aqueous solution was shaken with a litt,le ctlker to rcniove lienzene, nn(l air was bubbled through to remove bcnzeiic and ether.Tlic soliition, which mas slightly alkaline, was acidified with hydrochloric acid and evaporated on the water-bath. The crystalline residue mas dried over sulphuric The benzene portion left no residue on evaporation.DE MOUILPIED AND RULE : TETl~AKETOPIPEl~XZINE. 179 acid, ground, and extracted three times with alcohol quickly raised to the boiling point, The alcoholic solution -gave, on evaporation, a white crystalline solid, which after recrystallisation from absolute alcohol melted a t 124' (succinimide m. p. 135'). The yield was small, but the following reaction had evidently taken place to some extent : Action of Sodium Ethoxide on Ethyl Halonamate.--Ethyl mnlonamate was prepared (Ber., 1895, 28, 479) by the action of ft slow stream of hydrochloric acid gas on a well-cooled mixture of ethyl alcohol ancl ethyl cynnoacetate, and subsequent decomposition by heat of the hydro- chloride of iminomalonic ester which is produced.A certain amount of ammonium chloride was formed, and the pure ester was obtained by extracting the product with acetone and allowing the solution to evaporate slowly. The resulting oil crystallised readily 011 cooling and stirring, and the ester melted at 49-50', Thirteen grams were obtained from 25 grams of ethyl cyanoacetate. (a) Xodium EtiLoxide and Ethy? Malonumate i71 Benzene Solution.- 2.3 grams (1 atom) of sodium wire were suspended in 100 C.C. of dry benzene and dissolved in 4.6 grams of ethyl alcohol by the aid of heat.After cooling, 13.1 grams (1 mol.) of ethyl malonamate in benzene solution were added, and the whole allowed to stand overnight, The mixture was then heated on the water-bath for two hours, cooled, and the solid which had separated was filtered and dried. Yield about 16.2 grams. In this and all other similar reactions a deep indigo-blue colour developed, which only disappeared on the addition of water. The benzene portion was added to iced water, but no precipitation took place and the water remained neutral and colourless. The benzene left no residue on evaporation. The solid product was white ancl almost completely soluble in water, from which a buff -colourecl snbstance was precipitated by dilute hydro- chloric, though not by acetic acid. The bulk was treated with water, the residue separated, and on adding dilute hydrochloric acid t o the filtrate a pale brown amorphous precipitate was obtained ; the product burnt without melting on platinum foil, leaving a very slight residue. The yield was 7.2 grams.This substance dissolves readily in warm methyl alcohol, from which it separates as a crystalline powder on cooling; there is some slight decomposition as the mother liquor assumes a reddish tint. It is insoluble in ether, benzene or water, but dissolves readily in aqneous sodiuin hydrogen carbonate with eff er- vescence. Amnionin was evolved on heating the substance. A neutral solution gave a yellow precipitate with silver nitrate, reduction taking180 DE MOUILPLED AND RULE : TETRL4KE'l'OPLPERAZINE.place on warming; salts of copper, lead, and mercury were also obtained, but barium chloride only gave a precipitate on boiling. The crude product was crystallised from aqueous methyl alcohol. 0.1825 gave 23.2 C.C. moist nitrogen at 16" and 739 mm. N = 14.40. C,H,O,N requires N = 13.58 per cent. 2C,H50,N - H,O requires N = 14.89 per cent. 0.1065 required 6 C.C. Equivalent = 185.07. 0.1016 ,, 5.6 C.C. ,, = 189.6. 0.1021 required 5.3 C.C. Titration with baryta solution [l C.C. = 0.00822 Ba(OH),]. Titration with sodium hydroxide solution (1 C.C. = 0.0040 NaOH). Mean of three results = 188.49. C,H50,N (Malonamic acid) requires equivalent = 206. ZC,H,O,N - H,O requires equivalent = 188. Equivalent = 190.8. It has been found impossible t o hydrolyse ethyl malonaniate to malonamic acid by any of the usual methods.Malonic acid is the chief substance obtained together with some decomposition products. (b) Action of Xodium Ethoxide on Ethyl Maloiaamate i i ~ Absence of Benxene.-0*72 gram of sodium (I atom) was treated with just sufficient alcohol to convert the metal into sodium ethoxide, and while the latter was still molten 3.9 grams (I mol.) of ethyl malonamate were added. Reaction appeared t o take place immediately. The mixture was heated on the water-bath for half an hour and afterwards in a paraffin bath at 150" for one hour. After cooling it was treated with water,in which i t dissolved to a yellow solution, leaving only a trace of insoluble residue. The solution was filtered and acidified with hydrochloric acid, when a buff -coloured precipitate was obtained ; this was filtered, washed with cold water until free from chloride, and dried in a vacuum, Yield 0.75 gram.The product burnt completely on platinum foil, leaving no residue. It dissolved with effervescence in cold aqueous sodium hydrogen carbonate and was reprecipitated on adding hydrochloric acid to the solution. I n all its properties it resembled the substmce obtained by method (a) in benzene solution. The acid filtrate was neutralised with sodium carbonate solution, evaporated to a small bulk, and then allowed to stand over concentrated sulphuric acid in a vacuum. A red substance separated, which appeared to be similar t o the product obtained from the methyl alcoholic solution after recrgstallising the acid. This substance is being further investigated.DE MOUILPIED AND RULE : TETRAKETOPIPERAZINE.181 Action of Sodium Ethoxide on Oxamethccne. (a) In Benzene #olzction.--fJ*93 grams of sodium wire (1 atom) were suspended in 100 C.C. of dry benzene and just sufficient absolute alcohol added t o convert the metal completely into sodium ethoxide. Twenty grams of oxamethane (1 mol.) were then added, and the mixture was boiled for two hours on the water-bath. Some solid separated which was filtered off. The benzene gave on evaporation a small amount of unchanged oxamethane. The solid product was treated several times with cold water, when most of it dissolved ; the residue consisted of the sodium salt of tetra- ketopiperazine as described under method (b). The solution was neutralised with aqueous sodium hydrogen carbonate and concentrated on the water-bath.On adding absolute alcohol to the cold solution a voluminous white precipitate was obtained, which was filtered and dried in a vacuum. This sodium salt evolved ammonia when treated with caustic soda in the cold, thus pointing to the probability of its being sodium oxamate. 0.1993 gave 0.1251 Na2S0,. 0,1149 gave 12.7 C.C. moist nitrogen a t 23" and 761 mm. N = 12.47. Thus the reaction in benzene solution yields principally sodium oxamate. (b) Direct Action in Absence o$ Beizxene.-3.9 grams of sodium (1 atom) were dissolved in just sufficient absolute alcohol to convert the metal into sodium ethoxide. After cooling, 20 grams of oxamethane (1 mol.) were added and the mixture heated in the paraffin bath, At 125-130" a violent reaction took place ; the mixture became pale brown and alcohol was evolved. This was allowed to escape in order to prevent any hydrolysing action taking place.After heating at 140' for about one hour, the mass was cooled and treated several times with hot benzene in order to extract oxamethane, of which a small quantity remained unchanged. The product was then treated with cold water, in which it was only very slightly soluble, filtered, washed with water and alcohol, and dried. The weight of dry sodium salt obtained was 29 grams. It is a pale yellow powder, only sparingly soluble in cold water, and is decomposed when treated with hydrochloric acid, sodium chloride being formed, together with :t substance which on analysis gave figures corresponding to tetraketopiperazine. The latter substance burnt on platinum foil without melting and left a slight ash which gave an alkaline reaction towards litmus.It did not melt in a capillary tube, but slowly blackened above 250". Na= 20.32. C,H,O,NNa requires Na = 20.72 ; N = 12.61 per cent, (Theory for disodium tetraketopipernzine = 33.4 grams.)182 DE MOUILPIED AND RULE : TETRAKETOPIPERAZINE. It was insoluble in most organic solvents, but dissolved fairly readily in boiling glacial acetic acid, from which it crystdlisod in small, almost colourless monoclinic prisms. 1 t dissolved with eff ervescence in warm aqueous sodium hydrogen carbonate, the sodium salt being precipitated. The latter appears to be more insoluble than the free tetraketone; the potassium salt is more soluble.For analysis the recrystallised product mas heated for three hours at l l O o in a n air oven, in order t o remove any traces of acetic acid. 0 1855 gave 0 2312 CO, and 0.0421 H,O. 0.1819 ,, 32 C.C. moist nitrogen at 21' and 767 mm. N=20*22. 0.1828 ,, 32.1 C.C. ,, ,, ,, 22' ,, 774 mm. N=20*26. The numbers obtained indicate t h a t the substance was not quite pure, but recrystallisation was difficult owing to its insolubility. It is possible that boiling with acetic acid brings about decomposition to some extent. The substance was dissolved in a large excess of cold water, and titrated with baryta solution, using phenolphthalein as indicator (1 C.C. baryta = 0.0082 Ba(OH)2). C=33.99 ; H=2*52. C,H,O,N, requires c1= 33.80 ; H = 1.40 ; N 5 19.71 per cent, 0.1005 required 7*35 C.C.for neutralisation. This corresponds t o the formation of a monosodiiim salt, but the tendency to form a disodium salt was shown by the fact that on standing the red colour disappeared and further baryta was required before it reappeared. The point of complete neutralisation corresponding t o a disodium salt cannot, however, be reached in this way owing t o hydrolysis (see sodium salts). Sodium Xalts of ~eetrccketopi~eiiccxine. The mono-salt was obtained by treating the tetraketopiperazine with excess OF sodium -hydrogen carbonate solution in the cold. Partial solution took place with effervescence and reprecipitation on standing. On isolation the substance was obtained in long, white, silky needles, and proved t o be free from carbonate.It dissolved in water with the exception of a small yellow residue which was in every respect like the disodium salt, and the presence of this accounts for the slightly high number obtained on analysis : Equivalent found = 142.2. C,H,O,N, requires 142. 0.2130 dried at 110' gave 0.0977 Na280,. Na= 14.SCi. C,H0,N2Nn requires Na = 14.02 per cent. C,0,N,Na2 ,, Na=24*70 ,, ,,DE MODZLPIET) AND RIYLE : TETBAIiETOPIPERAZINE. 183 The disodium salt cannot be prepared in a pure state by the action of aqueous sodium hydroxide on the parent substance or on the mono- salt owing to the fact that a partial hydiiolysis takes place as already described. It is best prepared by the method given for the prepara- tion of tetraketopiperazine itself, that is, by treating oxamethane with the theoretical amount of sodiuixi ethoxide.Even in this case a certain amount of hydrolysis is caused by the necessary purification as shown by the figures obtained : 0.1936 dried a t 110" gave 0.1368 Na,SO,. Na = 22.S8. C,0,N2Na, requires Na = 24.70 per cent, C,HO,N,Na ,, Na=14*02 ,, ,, Silver SuZt.--This was obtained from the more soluble potassium salt 0.1042 gave 0.0632 Ag. as a voluminous white precipitate. After drying, Ag = 60.65. C,O,N,Ag, requires Ag = 60.67 per cent. C4H0,N,Ag ), Ag=43*37 ), ,, Hydrazone.-The tetraketopiperazine was dissolved in warm acetic acid and a solution of phenylhydrazine in acetic acid was added. The liquid became yellow and was warmed on the water-bath for five minutes, when fine needles separdted. The product was re- crystallised from acetic acid and'a buB- coloured crystalline substance obtained, which on heating began to sinter a t 250" and decomposed without melting completely below 300'. 0,1071 gave 22.4 C.C. moist nitrogen a t 20' and 767.5 mm. N = 24.15. C1,H80,N4 (monohydrazone) requires N = 24.1 3 per cent. C,6H,,0,K-, (dihydrazone) requires N = 26-08 per cent. Tetraketopiperazine dissolves sparingly in water, forming a solution which has an acid reaction ; on addition of ammonium hydroxide an ccmrnonizcnz salt is precipitated which dissolves on dilut,ion. This salt is decomposed by hydrochloric acid mitlh the formation of the parent substance. A mercz~ry salt was also obtained. On boiling with aniline a white crystalline compound is formed which sublimes with great readiness to a voluminous white product, melting between 210--215°. It is decomposed on treatment with boiling aqueous caustic potash, aniline being evolved, This product mill be further investigated. Tim ORGAXIC LABORATORIES, u N IVE 1:SIT Y O F L I V E I: 1'0 0 L .

ISSN:0368-1645    

DOI:10.1039/CT9079100176

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

184 SIMONSEN : SYNTHESIS OF TEREBIC, XVIL-Synthesis of Terebic, Terpen ylic, arid Honaoter- pen y lic Acids. BY JOHN LIONEL SIMONSEN (Schunck Research Fellow in the University of Manchester). CMe,* yH*CO,K 0 - COO CH, Terebic acid Tcrperiylic acid FMe,*$JH*CH,* CH,* C0,H O*CO* CH, Hoinoterpenylic acid are all produced by the action of oxidising agents on pinene and have always been considered of great importance, since the determination of their constitution has done much to solve the difficult problem of the constitution of pinene. The constitution of terebic acid has been very carefully investigated by Fittig and his pupils (Annalen, 1876, 180, 45 ; 1881,208, 37 ; 1883, 220, 254; 1884, 226, 365; 1899, 304, 320),and the acid has also been obtained synthetically by several methods (Bey., 1893, 26, 2047, 2315 ; Trans., 1899, 75, 531 ; Compt.reitd., 1906, 142, 1477), perhaps the most important being that carried out by Blaise (Compt. rend., l89S, 126, 349), who obtained it by the action of acetone on ethyl bromosuccinate in the presence of the zinc-copper couple. The formula given above for terpenylic acid was first suggested by Wallach (Annalen, 1830, 259, 322) and subsequently shown to be cor- rect by the careful investigations of Fittig (Annalen, 1896, 288, 176), Mahla and Tiemann (Ber., 1896, 29, 928), and Schryver (Trans., 1893, 63, 133s). Lawrence (Trans., 1899, 75, 531) succeeded in obtaining this acid synthetically by oxidising P-isopropylglutaric acid by means of chromic acid solution, and thus there can be no doubt as to its constitution.Homoterpenylic acid was first obtained by Btteyer (Ber., 1896, 29, 19 19) by the oxidation of homoterpenoylformic acid (an oxidation p o - duct of pinene) with nitric acid or l e d oxide. $! Me,*CH*CH, C0,H ’ O*CO*CH, The three acids, I ? 9 $‘Me,-F)H*CH2*CH,*C0.C0,TI $JMe,-$X*CH,* CH,*CO,H O*CO*CH, O-CO*CH, -+ I n conjunction with Villiger (Be?.., 1896, 29, 1923) he also obtained it by the oxidation of nopinone : 7 Xe,-yH*CH,* CH,*CO,H -+ O*CO*CH, CH, /cH--yo ?Me, C;‘H2 ‘CH--CH,TERPENYLIC, AND HOMOTERPENYLIC ACIDS. 185 Its constitution was deduced by Baeyer (Ber., 1896, 29, 2775) from the fact that on oxidation it yielded a mixture of terebic and terpenylic acids. In considering the formu1:e of these acids i t seemed probable that a convenient method of synthesis mould be to act on the corresponding keto-ester with magnesium methyl iodide, especially since it is known that in such cases the keto-group reacts with the reagent before the carbethoxy-group is attacked (compare W, H. Perkin, jun., Trans., 1902, 85, 654).It has already been noticed (Grignard, Contpt. rend., 1902, 135, 629; Jones and Tattersall, Trans., 1904, 85, 1691) thttt keto- esters containing the keto-group in the y-position react with magnesium methyl iodide with the direct formation of lactones. This process was first applied to ethyl acetosuccinate, which, when treated with magnesium methyl iodide, is directly converted into ethyl terebate : COXe*CH(CO,Et).CH,*CO,Et -+ Cilte,(OMgI)*CH(C0,Et)*CH2*C02Et -+ vNe2-$7H. CO,Et O*CO*CH, The yield of this ester is good, and, since simply boiling with hydro- cliloric acid converts i t readily into terebic acid, it is probable that this synthesis constitutes the most convenient method for the preparation of this acid.Under similar conditions ethyl P-acetylglutnrate is found to react readily with magnesiuni methyl iodide with formation of ethyl terpenylate : CO.$t*C'H,*CH( COMe) CH,*CO,E t -+ ~O,Et~CfH,~~H(~IZIe,~OMgI)CH~*CO,%t -+ 7 Me,-~H-CH,*CO,Et 0 CO CH, This ester is again obtained in a good yield and, when digested with hydrochloric acid, is at once converted into terpenylic acid. In order to synthesiee homoterpenylic acid it was necessary in the first place to prepare P-acetyladipic acid. This was readily done by treating the sodiuni compound of ethyl acetosuccinate with ethyl /3-iodopropionate, when ethyl P-acetylbutaue-ap8-tricarboxylate is formed : COMe*CNa(C0,Et)*CH;C02Et -t CH,I*CH,*CO,Et -+ VOL.XCI. + NaI. COMe*$!(CO,Et)*Cfl,*CO,Et CH,*CH,*CO,Et 0186 SIMONSEN : YY NTHESIS OF TEREBIC, When this ester is digested with hydrochloric acid it is hydrolysed, carbon dioxide is eliminated, and P-acetylndipic acid, a crystalline snbstance melting at 102", is produced. with forination of elhyl homoterpenylztte : COMe*CH(CH,*CO,Et) *CH,* CH,*CO,Et -+ CONc.C~I(CH,*CO,I)*CH,~CH,*CO,H, The ester of this acid reacts readily with magnesiuiii methyl iodide C~~e,(ORlgLj~CH(CHI,.CO,Et)*CH,*CHz=COzEt -+ ~Rle,-C1H*CI~2.CH,*C0,Et O*CO-CH, This ester on hydrolysis yielded hornoteibpenylic acid which melted a t 100-101" and hLtd all the properties ascribed to it by Baeyer.&ntiLesis of TeTebic Acid, 0,C0.CH,7 qMe,-yH*CO,H .-In preparing this acid, ethyl acetosuccinate (2 1 granis), mixed with about four times its volume of dry ether, was slowly added to a well-cooled ethereal solution of magnesium methyl iodide (prepared from 2 1 grains of methyl iodide and 4 grains of magnesiuni). The reaction is extremely vigorous and the white inagnesiuni compound soon separates. A fter standing over- night the niagneviuiu compound was carcEull y decomposed by the slow addition of water and dilute hydrochloric acid; the ethereal layer was then sepiwatcd and the acid solution extracted twice with small quanti- ties of ether. The mixed ethereal extrwts were washed with a little sodium hydrogen sulphite solution, to remove iodine, and afterwards dried and evnporiited.The residual yellow oil was fractionated under reduced pressure (1 8 mm.), when it all passed over at 140-150°, and, on refractionating, almost the whole quantity disrilled constantly at 145-147' (15 mm.), and evidently contained some unchanged ethyl acetosuccinate, since it still gave a violet coloration with ferric chloride. I n order to obtain terebic acid the crude product (17 grams) was hydrolysed by boiling in a reflux apparatus with concentrated hydro- chloric acid (50 c.c.). Owing to the presence of the ethyl acetosuccin- ate some carbon dioxide was evolved at first and after heating for eight hours the oil had completely dissolved. The hydrochloric acid was eyaporated, when a semi-solid brown mass remained, whiah was dissolved in hot water and boiled for a few minutes with animal charcoal. The solution was filtered :md concentrated, when, on cooling, colour- l c ss needles were deposited.After collecting and recrystallising from water, the following results, agreeing with those required by terebic acid were obtained on analysis : 0.1534 gave 0.2978 CO, and 0.0850 H20. C = 53.2 ; H = 6.2. C7Hlo0, requires C = 53.2 ; H = 6.3 per cent.TERPENYLIC, AND HONOTERPENYLIC ACIDS. 187 The acid melted at 1 7 4 O , which is the melting point given by Fittig and Melck (AnmcZeu, 1876, 180,45) to terebic acid. The characteristic barium salt of the diaterebic acid wus also prepsred by boiling the solu- tion of terebic acicl with excess of bnrytsL, removing the excess with carbon dioxide, and precipitating the barium diaterebate wibli alcohol.C7H1,0,Ba + 3H,O requires Ba = 37.5 per cent, 0,4589 gave 0,2940 BaSO,. Ba= 37.6. ~A%e,-QH-(_1H,*C02H O*CO*CH', I'erpen y I ic Acid, .---Ethyl P-acetglglutarate, C0,Et*CH,-CH(COIVle)~CH2~~~02Et, was found to be most readily obtained from the dilactone of /3-acetylglutaric acid, I CH, I ,bythe metliocl described by Fittig (Annden, 1900, 314, 2 l), who obtained this dilactone from the sodium salt of tricnrbnllylic acid by heating with acetic anhydride. I K ~ preparing terpenylic acid, ethyl P-acetylglutnr:xte (20 grams), dissolved in about four times its volume of dry ether, was slowly added to a well-cooled ethereal solution of magnesium methyl iodide (prepared froin 5 grams of magnesium and 25 grams of methyl iodide). After standing overnight the magnesium couipouiid was cautiously decom- posed with water and dilute hydrocliloric acid ; the ethereal layer was then separated and the acid solution extracted twice with a little ether.The coinbiirlecl etliored extracts were wadled with a little sodium hydrogen sulphite solution, to remove iodine, and afterwards dried and evaporated. The oil thus obtained when fractioned under reduced pressure (1 5 ruin.) passed over almost completely between 140-175", a small quantity only of a substance of higher boiling point remaining in the distilling flask. On refractionating, the distillate was readily separated into two por- tions boiling at 155-161Oand 169-171' (15 mix.), and the high boil- ing fraction, when cooled in a freezing mixture, ci-ystallised.The mass was left in contact with porous porcelain until free from oil and then purified by recryst allisation from ether, when colowless crystals were obtained which inelted a t 37"; this is the melting point given to ethyl terpenylate by Pittig and Levy (Anncclen, 1899, 258, 112), and the identity was confirmed by analysis aud subsequent hydrolysis. O-?I e-0 co.t5r-I*co 0.1599 gave 0,3506 CO, and 0.1122 H,O. C1,t-Tl,O, requires CI = 60.0 ; H = 8.0 per cent. The ethyl terpenylate (6 grams) was hydrolysed by boiling with con- centrated hydrochloric acid (50 c:c.) when, after eight hours, the oil had completely dissolved. 'rhe hydrochloric acid was removed by evapora- C = 59.8 ; H = 7.8.0 2188 SIMONSEN : SYNTHESIS OF TEREBIC, tion on the water-bath and the residual crystalline miss purified by recrystallising from water with the aid of animal charcoal. I n this way colourless prisms were obtained which showed the characteristic properties of terpenylic acid ; namely, when left in the air until dry, the melting point was 56", but after exposure over sulphuric acid for some days the melting point was found to be 89" (compare Lawrence, loc. cit.). The acid melting a t 89" gave the following results on analysis : 0,1611 gave 0.3301 CO, and 0.1006 H,O. C = 55.9 ; H = 6.9. C,HI2O, requires C = 55.8 ; H = 7.0 per cent. P-Acetyladipic Acid, COMe*CH(CH,*CO,H)*CH,*CH,*CO,III. C0,Et *CH2*CH,*CAc(C0,Et) CH,-CO,Et. This substance, which has not previously been described, was readily obtained as follows.Sodium (5.7 grams) was dissolved in alcohol (100 c.c.), and, after cooling, ethyl acetosnccinate (54 grams) was added. The sodium compound was then mixed with ethyl /3-iodopropionate (60 grams) in small quantities at a time, any rise of temperature being carefully avoided by cooling with water. After standing overnight the mixture was heated on the water-bath for half an hour and the liquid, which should be quite neutral, was cooled and diluted with water. A heavy oil separated which was extracted three times with ether ; the ethereal solution was well washed with water to remove alcohol, dried, and evaporated. The oil thus obtained was fractionated under reduced pressure (16 mm.), when almost the whole quantity (70 grams) passed over between 195-205", and after refractionation at 200-201° (14 mil?.).Cl,H,,07 requires C = 56.9 ; H = 7.6 per cent. Preparation of ethyl P-acetylbutane-ap8-t&ar6oxylate7 0.1643 gave 0.3418 CO, and 0.1120 H,O. Ethyl p-acetylbuta?ze-a/36-lrical.boxyEate is EL viscid colourless oil having a pleasant ethereal odour. It gives 110 coloration with ferric chloride. I n order to prepare P-acetyladipic acid this ester (70 grams) was hydrolysed by boiling with concentrated hydrochloric acid (1.10 c.c.) in a flask provided with a reflux condenser. At first there was much frothing owing to the evolution of carbon dioxide, and after eight hours water (100 c.c.) was added and the solution boiled for a further period of eight hours. The hydrochloric acid was then removed on the water- bath, when a very viscous yellow syrup was obtained which, on vigorous rubbing, solidified t o a crystalline mass.The P-acetyladipic acid (40 grams) mas crystallised from dry ether, from which it separated in plates, melting at 102". That this was the C - 5 6 . 7 ; H=7.6.TERPENYLIC, AND HOMOTERPENYLIC ACIDS, 189 acid, and not either the dilactone or the semilactone of P-acetyladipic acid, as might be expected from analogy with /3-acetylglutaric acid, is shown by the following analysis : 0,1423 gave 0,2653 CO, and 0.0824 H,O. C1,H1,O, requires C = 5 1.1 ; H = 6.4 per cent. P-dcetyladipic acid is readily soluble in water, alcohol, acetone, acetic acid, formic acid, or ethyl acetate in the cold; sparingly SO in ether, benzene, or chloroform, even on boiling ; and almost insoluble in light petroleum.The basicity of the acid was determined in the first place by titration with standard aqueous caustic potash. 0.1349 neutralised 0.0793 KOH, whereas this amount of a dibasic acid, CsHI20,, should neutralise 0.0797 KOH. The silver salt of P-acetyladipic acid was prepared by adding silver nitrate to a slightly alkaline solution of the ammonium salt, when it separated a s a flocculent precipitate readily soluble in hot water from which it was crgstallised. C=50.8; H=6*4. 0.1 117 gave 0.0598 Ag. C,H1,0,Ag2 requires Ag = 53.7 per cent. P-Acetyladipic acid sernicarbaxone. -When an aqueous solution of P-acetyladipic acid was mixed with semicarbazide, hydrochloride, and sodium acetate nothing separated, but after some time the semi' carbazone was slowly deposited in warty masses.After crystallising from hot water in which the substance is readily soluble, the following results were obtained : Ag = 53.5. 0,2071 gave 0.3109 GO, and 0,1175 H,O. C = 40.9 ; H = 6.3. 0,1654 ,, 22.3 C.C. nitrogen a t 19O and 767 mm. N = 15.7. C,H,,O,N,,H,O requires C = 41.1 ; H = 6.5 ; N = 15.9 per cent. This substance, which melts at 89-90' and is sparingly soluble in cold water, is probably the semicarbazone of P-acetyladipic acid, crystallising with one molecule of water of crystallisation. That it is not simply the semicarbazide salt of the acid is shown by the fact that it dissolves instantly in sodium hydrogen carbonate solution. Ethyl P-acetyZadipccte.-Zn order to prepare this ester P-acetyladipic acid (35 grams) was dissolved in a mixture of alcohol (175 c.c.) and sulphuric acid (17 c.c.) and boiled for two days on the water-bath.After cooling, the mixture was poured into water, when a heavy oil separated which was extracted twice with ether, The ethereal extract was well washed with dilute aqueous sodium carbonate, dried, evapor- ated, and the yellow oil fractioned under reduced pressure (1 8 mm.), when it distilled constantly a t 179'. 0.1501 gave 0.3237 CO, and 0*1108 H20. C: = 58.8 ; H = 8.2. Cl,H2,0, requires C = 59.0 ; H = 8.2 per cent.190 TERERIC, 'I'ERPENY LIC, AND HOMOTERPENPIJC ACIDS. Ethyl P-acetyladipate is a colourless oil with a slight but rather It is insoluble in water but readily miscible with unpleasant odour.most organic solvents. ~Rle,-C;EI.CII,*CH,*CO,TI 0-CO CH, Preparcc t i o n of Homoteypen ylic Acid, I n the preparation of homoterpenylic ester, P-acetyladipic ester (29 grams), dissolved in about four times its voluine of dry ether, mas slowly added t o a well-cooled ethereal solution of magnesium methyl iodide (prepared from 4 grams of magnesium and 25 grams of methyl iodide). After standing overnight the iiiagnesinm compound was cautiously decomposed with water and dilute hydrochloric acid, the ethereal layer separated, and the acid solution extracted twice with small quantities of ether. The combined ethereal extract was washed with sodium hydrogen sulphite solution, dried and evaporated , when a viscid oil was obtained which after several fractionations dis- tilled constantly at 1 (1 8 mm.). 0.1329 gave 0.3140 CO, and 0.1041 H,O.C = 61.5 ; H=S*3. C,,H,,O, requires C = 61.7 ; H = 8.4 per cent. Ethyl Imnioterpenylate, which has not been previously described, is a viscous colourless oil with a pleasant ethereal odour. It does not solidify even when cooled to - 15'. Ethyl homoterpenylate was readily hydrolysed by digestion with concentrated hydrochloric acid, and, after evaporating, a viscid colour- less syrup was obtained which solidified on cooling. The substance was purified by crystallising from hot water with the aid of animal charcoal and separated in colourless plates melting a t 1OO-10lo. Baeyer (Rer., 1896, 29, 1919) gives the melting point as 98-101O when crybtalliscd from water and as 100-102.5° when ether is the solvent. 0.1866 gave 0.3950 C@, and 0.1266 H20. C = 57.7 ; H = 7.5. CSH,,O, requires C = 58.0 ; 13 = 7.5 per cent. By titration with standard aqueous caustic potash in the cold, the 0.1650 neutralised 0.04963 KOH, whereas this amount of a mono- There can, therefore, be 110 doubt that the synthetical acid is ident'ical acid was shown to be monobasic. basic acid of the formula C,H,,@, should neutralise 0.04967 KOH. with the hornoterpenylic acid obtained by the oxidation of pinene. I n conclusion I wish to thank Professor W. K. Perkin for the great interest he has shown i n this research and also for niuch valuable advice and assistance. THE SCHlJNCIC LABOKATOXY, THE UNIVEKSITP, MANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9079100184

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

PREPARATION OF CHROMY L DICHTAORIDE. 191 Chant y 1 Dichlo ride. By HERBERT DRAKE T,AW and FREDERICK MOLLWO PERKIN. THE method usudly given for the preparation of chromyl dichloride is t o act on a mixture of potassium clichromate and sodium chloride with concentrated sulphuric aci(1. g t a r d (Ann. China. Phys , 1881, [ v 3, 23, 218) used fuiriing snlphuric acid and noticed that clilorine was illways given off during the reaction, but he succeeded in obtaining a yield of 70 per cent. of chromyl dichloride. As n matter of fact, a certain amount of reduction of tho chromyl chloride with the excess of hydro- chloric acid, liberated in the reaction, always takes place, even when ordinary strong snlphiiric acid is used The objection t o the above method of prep,wation is the extreme frothing and fuming which occurs.I n order to lessen the frothing, it is generally recom- mended to fuse sodium chloride and potassium dichromate together in equivalent proportions, and then to break up the fused product into small pieces. Even when this is done the operation requires constant attention, and it is very difficult t o distil the chromyl chloride owing t o the frothing. Moissan (Conzpf. ?*end., 1884, 98, 582) prepared it by passing dry hydrogen chloride over chromic anhydride, but even by this method a certain amount of reduction takes place, a green substance being left behind a t the end of the reaction. We tried several methods for preparing the product, for example, that of passing dry hydrogen chloride into chromic anhydride sus- pended in concentrated sulphuric acid, the mixture being cooled by running water.This method gave practically theoretical results, but the process was tedious owing to a tendency of the chromic anhydride to cake in the sulphuric acid, when i t is only slowly acted on by the hydrochloric acid. W e found the most satisfactory method mas to dissolve chromic arihydride in concentrated hydrochloric acid and then to add an excess of strong snlphuric acid. Chromic anhydride clissolves with the greatest ease in concentrated hydrochloric acid, forming a brownish-red so1ut)ion. On adding con- centrated sulphnric acid to this solution and cooling, chromyl dichloricle separates, and, being denser than the hydrochlol.ic-sulphuric acid solu- tion, sinks to the bottom, and is readily isolated by means of a t'ap funnel.We find t h a t if 1:trge quantities of chromic anhydride are acted on at one time the reaction does not proceed as snioothlyas when smaller quantities are used, owing to the difficulty of cooling the mix- ture and thus keeping the reaction under control. When the reaction becomes too vigorous, and consequently heating results, tbe yield is192 PREPAHATION OF CHROMYL DICHLORIDE. much smaller, owing to reduction of the chromyl dichloride. The best results were obtained by proceeding as follows. Fifty grams of chromic anhydride are dissolved in rather more than the calculated quantity of concentrated hydrochloric acid (1 70 c.c.) in a 1 s litre flask and then 100 C.C. of concentrated sulphuric acid added in quantities of about 20 C.C.a t one time, the mixture being cooled between each addition. The sulpharic acid should be poured into the middle of the solution and not clown the sides of the flask, as i t then mixes bettey and very little fuming takes place. The whole of the sulphuric acid inny be added in the course of about two minutes. I n order to prepare larger quantities, about six flasks are taken, and into each flask 50 grams of chromic anhydride are placed and then the requisite quantity of hydrochloric acid. The chromic anhydride immediately dissolves. Sulphuric acid, 100 c.c., is then added to each flask, cooling between the additions of the acid, and when the reaction in the six flasks is complete, the contents are poured into a large separating funnel and allowed to stand for twenty minutes. At the end of this time the whole of the chromyl di- chloride mill have separated as an under layer, and is then drawn off from the specifically lighter layer of sulphuric and hydrochloric acids.Proceeding in this manner, there is no difficulty in preparing a kilo- gram or more in one hour. Dry air is now aspirated through the chromyl dichloride for about an hour in order to remove any dissolved hydrochloric acid. It may then be distilled, when i t will be found to boil constantly a t 115-11Ci0. For most purposes, however, it is sufficiently pure without this operation. Our own experience is that, provided i t is freed from hydrochloric acid by aspirating air through i t and is then distilled to remove any sulphuric acid, it may be preserved for a long time. It is, however, essential to have the bottles well stoppered to exclude moisture, as, owing to absorption of the latter, the stoppers often become fixed. I n using a hurette or separating funnel the taps should never be lubricated with vaseline or oil, because of the vigorous action of the chramyl di- chloride on hydrocarbons. It is often stated that chromyl dichloride does not keep well. CHEMICAL LABORATORY, BO~LOUGII POLYTECHNIC INSTITUTE, I,ONDON, S. E.

ISSN:0368-1645    

DOI:10.1039/CT9079100191

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

RENZOYL DERIVATIVES OF N-METIIYLSALICYLAMIDE. 193 By JAMES MCCONNAN and MORRIS EDGAR MARPLES. IT has been shown (Titherley and Hicks, Trans., 1905, 87, 1207 and McConnan and Titherley, Trans., 1906, 89, 1318) that both 0-acyl and N-acyl derivatives of salicylamide are unstable substances in the sense that they show a tendency to rearrange, and, under suitable conditions, can be converted into each other; and the view has been expressed that these changes take place through an intermediate cyclic metoxazone form, :xcorrling to the scheme : CO*NH, --f CO-NH , R -+ ,,<CO*NH*@O.R cf$H4<o*Co*R f- C,H,. 0 >‘<OH t- 6 4 OH The berizoyl derivatives of N-methylsalicylamide have been in- vestigated with the object of throwing further light on this interest- ing change. 0-Benzoyl-LV-methylsalicylamide is easily obtained by pyridine-benzoylation of X-methylsalicylamide.I n its solubilities and its decomposition by cold sulphuric acid to benzoic acid and N-methylsalicylamide it resembles 0-benzoylsalicylamide ; it behaves abnormally, however, in all those reactions by which 0-benzoyl salicylamide is rearranged. to Gerhardt’s N-benzoy lsslicylamide. The latter rearrangement takes place, for instance, when 0-benzoyl- salicylamide is melted, when i t is boiled with water, on leaving it to stand in pyridino solution for fifteen days, or on treatment with aqueous alkali. IJnder the first three conditions 0-b:nzoyl- N-methylsalicylamide is not affected, but on treatment with alkali it dissolves slowly with development of a yellow colour.Whilst in the case of. 0-benzoylsalicylamide the yellow colour, due to the formation of the stable sodium derivative of N-benzoylsalicylamide, is persistent, with 0-benzoyl-N-methylsalicylamide the colour is transient and disappears in from thirt,y seconds to two minutes, according to the conditions of the experiment. There can be no doubt that similar rearrangement occurs, forming the sodium derivative of N- benzoyl- Z-met h ylsalicy lamide : ‘GH4<OBz CO-NIIMe -+ C,H4<ENMeBz, but the latter is almost instantly hydrolysed to benzoic acid and N-methylsalicylamide ; this assumption is necessary, both by analogy with the simpler case mentioned, and from the fact that ,!-methyl- sa licy lamide yields a colourless solution in alkalis. Numerous attempts were made t o isolate N-benzoyl-N-methylsnlicylamide from the yellow solution, using 0-benzoyl-Xmethylsalicylamide, both solid and in alcoholic solution, and varying the nature and strength194 hlcCONNAN AND MARPIJES : of the alkaline reagent, but in all cases hydrolysis appeared to be practically instantaneous, and addition of dilute acid to the yellow solution produced at most a precipitate of unchanged 0-benzoyl-iV- methyl salicylamide.The extreme instability of AT-benzoyl-iV-methylsalicylamide is con- firmed by the study of O-iV-dihenzoyl-~~~-methylsalicylamid~, obtained by pyridiiie benzoylation of 0-benzoyl-itr-methylsalicylamide. Were its behnviour normal it should be decomposed by cold concentrated sulphuric acid into benzoic acid and N-benzoyl-N-metliylsalicylamide (compare 0-N-dibenzoyls dicylamide, McConnan and Titherley, Trans., 1906, 89, 1327), since it has been found in general that this reagent eliminates 0-acyl groups, but leaves N-acyl derivatives intact.0-N- Dibenzoyl-N-methylsalicylamide dissolves in sulphuric acid and is decomposed ultimately into benzoic acid and N-methylsalicylamide, but if a relatively small quantity of acid is used 0-benzoyl-,'V-methyl- salicylamide can be isolated as an intermediate product. This behaviour is analogous to that of trihenzoylsalicylamide, and is represented by the scheme : Since iV-N-dimethylsalicylamide is a stabie substance melting a t 164", i t appears that although derivatives of the general formula C,FT,<~~NRz are stable, substances of the t y p e . CO *NRAc CGH,<OH are too unstable t o permit OF isolation.This observation is of considerable interest, since McConnan and Titherley have already shown (Zoc. cit.) that N-N-diacyl salicylamides, CO*N(CO*R), CO N (C 0.R) ( CO OR,) C,I.T,<()H Or 'GH4<OH are too unstable to exist. EXPERIMENTAL. N - M ethy Zsalic ylamide , C6H4<g Me .-T hi s compound, which has not been hitherto described, was prepared by the action of aqueous methylamine on salol. 214 grams of salol and 200 grams of 33 per cent. methylamine solution were allowed to stand for twelve hours with occasional shaking; the mixture became warm, and the reaction was completed by warming until all was in solution. The excess of methylamine- was distilled off, the residue acidified by diluteBENZOYL DERlVA’I’IVES OF N-METHPLSALICYLAh~IDE. 195 hydrochloric acid, and the phenol distilled i n steam ; the solution was filtered hot, and deposited N-methylsalicylamide on cooling ; a further crop of crystals was obtained by concentrating the mother liquor.The prodiict was i~ecrystallised from :dilute alcohol ; yield : 95 per cent, of theory : 0.1867 gave 14.8 C.C. nitrogen a t 19’ and 7’72 mm. CsH<,O2N requires N = 9-27 per cent. N-n4eth~lsalicyZccnzide me1 ts at 89’ ; it is readily soluble in alcohol, ether, benzene, or chloroform, and crystallises from dilute alcohol in colourless plates ; its behaviour with alkaline reagents and with ferric chloride is in every respect analogous t o that of salicylamide. O-Belzxo?ll-N-rnetl’Lylsal~cy~a~~~~~e, C B H 4 < ~ ~ ~ N ’!‘Ie, was prepared by adding 14 grams of benzoyl chloride to a solution of 15 grams of N-methylsalicylamide in 45 grams of pyridine at - 15’; the product was isolated i n the usual way and recrystallised from benzene.N = 9.26. 0,1785 gave 9.0 C.C. nitrogen at 21’ and 745 mm. C,,H,,O,N requires N - 5.49 per cent. 0-Benxoyl-N-metl~ylscclicylamide melts a t 122’ ; it is readily soluble in cold alcohol or chloroform, sparingly so in ether; it crystallises from benzene in transparent, prismatic needles. On stirring with aqueous alkali it dissolves slowly, with a transient yellow colour, being almost instantly hydrolysed to benzoic acid and ,!-methyl- salicylamide ; it is similarly decomposed by coid concentrated sulphuric acid. Ethyl benzoate is obtained as a decomposition product when a n alcoholic solution of 0-benzoyl-N-methylsalicylamide is treated with alkali ; with sodium ethoxide or aqueous sodium hydroxide the decomposition was complete in thirty t o sixty seconds (measured by the disappearance of the yellow colour), hut with alcoholic ammonia no colour change was observed, and the decomposition required several hours.O-N-DibenxoyZ-N-nzethylsalic~/aniic~, C , H , < ~ ~ ~ N ” e B z .--2*8 Grams of benzoyl chloride were added to a solution of 5 grams of O-benzoyl- N-methylsalicylarnide in 15 grams of pyridine ; after standing twelve hours the mass was stirred with absolute ether, the ethereal solution was decanted from the pgridine hydrochloride, washed with dilute sulphuric acid, and dried with sodium sulphate. O-N-Dibsnxoyl-N-naelhylsnEicylcclrzide separated on adding light petroleum, and was crystnllised from a mixture of ether and light petroleum, from which it was obtained in large hexagonal prisms. N = 5.63. 0.1754 gave 5.9 C.C. nitrogen at 19” and 772 mm. N=3-93. C,,H170,N requires N = 3.90 per cent.196 MCCONNAN DISALICYLAMIDE. Dibenzoyl-iV-methylsalicylamide melts at 85" ; it is readily soluble in alcohol, ether, or chloroform, moderately SO in benzene, and very sparingly so i n light petroleum. It is insoluble in cold aqueous caustic soda, but on boiling i t is hydrolysed slowly to N-methyl- snlicylamicle and loenzoic wid. The same decomposition products were obtained by dissolving i t in excess of cold concentrated sulphuric acid and allowing t o stand for f o u r days, whilst with a smaller quantity of sulphuric acid and only four hours' action 0-benzoyl-N- methylsdicylamide was obtained as decomposition product. ORGANIC LAI~OKATORY, UNIVEIMITY OF LIVERPOOL.

ISSN:0368-1645    

DOI:10.1039/CT9079100193

出版商:RSC    

年代:1907

数据来源: RSC

摘要:

196 McCONNAN : DIYALICYLAMIDE. XX. -Disalic ylamide. By JAMES 31CCONNAN. DISALICYLAblIDE (1EfO*C,,H,*CO'NHgCO*C,H4*OH) was first obtained by Schulerud (J. pi.. Chem., lSS0, [ii], 22, 289) by the action of hydrogen chloride on heated salicylamide. Subsequently G. Cohn (.I pr. Chem., 1900, [ii], 61, 552) found that disalicylamide is formed when salol and salicylamide are heated together at 215-220' ; at the same time he appears to have obtained n second compound which wa Y formulated as 0-salicylsalicylamide, C,H,(CO*NH2)*O*CO*C,jH4*OH, the properties of which were, however, practically identical with those of disalicylamide (Pntentschift, No. 11 I ,65 6). These two compounds are recorded in Beilstein's Handbuch (Erganxungsbaiad II., 892, 893), but the author, from previous work on acyl derivatives of salicylamide (Trans., 1906, 89, 1318), was led t o doubt Cohn's conclusions as t o the supposed 0-salicylsalicylamide.The properties assigned to the latter by Cohn were inconsistent with the 0-salicyl formula, as was also its mode of formation from salol and salicylamide, inasmuch as ammonia is evolved in the reaction ; it is now known that 0-acyl derivatives of salicylamide are instantly rearranged t o the corresponding N-acyl derivatives by ammonia. The reaction between salol and salicylamide has been repeated with the object of investigating this point, and it has been proved that 0-salicylsalicylamide is not formed. Two compounds are produced, namely : (1) Disalicylamide : HO*C,H,*CO*NH*CO*C,H4*OH, m. p. 203".McCONNAN : DISALICPLAMIDE. 197 (2) Polysalicylnitrile, m.11. 29 7" (Limpricht, A?male)z, 1856, 98, 261, &c.). The proportions of eash vary, and the amount of polysalicylnitrile formed increases rapidly with the proportion of salicylamide used. 0-Salicylsalicylamide has been obtained, however, by the rearrange- ment of disalicylamide by boiling with glacial acetic acid, the change taking place, according to the author's view, through an intermediate cyclic form : ,COON H* CO *C',H,*OH -+ $IO*NH C,H,*OH -+ C6H4<OK f- C,H,-O >"<OH t- GO-NH, CGH4<O*CO*C6H4*OH (compxe rearrangement of AT-benzoylsalicylamide, McConnan and Titherley,-Trans., 1906, 89, 132 1 ). 0-Salicylsalicjlamide undergoes the reverse change into disalicyl- amide on meltiug, on boiling with water, on standing in pyridine solution, or on treatment with alkaline reagents ; the two compounds are, in fact, in every respect andogous to the two benzoyl and the two acetyl salicylamides already described (106.cii., and Titherleg and Hicks, Trans., 1905, 87, 1207). The study of di:alicylamide has led t o the detection of an error in the recent work on acyl derivatives of salicylsmide (hlcconnan and Titherley, Trans., 1906, 89, 1326); it mas stated that the action of benzoyl chloride on a pyridine solution of Gerhardt's benzoyl salicyl- ainide a t - 15" led to the formation of two compounds : ( 1 ) O-A'-Dibenzoylsalicylamide : C,iH4<~~~NHGZ (m. p. 12S"). ( 2 ) 2 : '2-Phenyl-0-beiizoyl hydroxybenzometoxazone : All subsequent attempts to prepare the second compound in the same way failed, and i t has been shown that the formation of the derivative melting at 160" was due to the unsuspected presence of disalicylamide as impurity in the benzoylsalicylamide used.* It has been found t h a t the compound melting at 160' is easily obtained by pyridine benzoylation of disalicylamide, and that it is dibonzoyldi- salicylarnide : CsH,<2Bz CO-NH- BzO>CGH4.CO The view taken by lSlcConnan and Titherley of the tautomeric character of Gerhardt's benzoylsalicylamide is thus deprived of one * The con litions for the Iiroduction of disslicylainide :ire piesent in Gerhnrdt's method of preparing L~iizoylj'~licylaiiicle, siiicc the iiie thod iuvolves heating sitlicyl- aniide iu pieseiice of hycirocl~loric acid.198 McCONNAN : DISALICYLAMIDE.point of evidence previously adduced in it.s support ; this view, how- ever, has since been confirmed by new experimental evidence t o be published shortly. E s P E R I hi E N T A L. 42.8 Grams of salol (1 mol.) were heated with 41.1 granis of salicyl- amicle (18 rnols.) for two hours at 220°, the phenol forrnecl by the reaction being allowed to distil off. The product was poured into 100 C.C. of alcohol, and the resulting yellow precipitate, consisting of a mixture of disalicylamicle and polysalicylnitrile, W R S separated. The mixture was boiled for three hours with 300 C.C. of glacial acetic acid, when the disalicylainide completely dissolved, being a t the same time partly rearranged to 0-salicylsalicylamicle. The insolubie polynitrile was filtered from the Lot solution and naslied with acetic acid and water ; i t weighed 4 grams and melted a t 297".The hot acetic acid solution, on cooling and diluting with water, deposited 20 grams of a mixture of diealicylarnicle and 0-salicylsalicgl- amide ; these were separated from the clry mixture by extracting with boiling benzene, in which disnlicyla,mide is insoluble. 0-Salicylsalicyl- amide crystallised in a pure state fiom the hot benzene filtrate; it was filtered and washed with light petr oleuin. 0.2442 gave 11.7 C.C. nitrogen at 21" and 772 mm. o-X(~lic?/lsaZicylccr~~~~e melts a t 15'io, but solidifies in the course of a few seconds owing to rear1 angemenb t o disalicylarnide, which then melts at 200'. It is readily soluble in alcohol or hot benzene, moderately so in ether, sparingly so in light petroleum or cold benzene ; it crystallises from benzene iu colourless plates. I t s alcoholic solution gives with aqueous ferric chloride an intense red colour, which changes to violet on diluting with water.0-Salicy lsalicylamide is quantita- tively rearranged t o disalicylarnide on boiling p i t h water. It is readily soluble in pyridine, and the solution gradually acquires a yellvw colour owing t o the formation of disalicylamide, and the rearrangement is complete in six days. Aqueous alkalis dissolve it rapidly, yielding a yellow solution from which disalicylamide is precipitated on acidify- i n g ; in the case of sodium hydroxide, the sparingly soluble orange salt of disalicylainide is first formed and dissolves on dilution, O-Salicylsalicylaruide is rapidly decomposed by cold, strong sulphuric acid into salicylamide and salicylic acid (compare behaviour of its isomericle with strong sulphuric acid).I t s constitution follows from the close similarity between i t s properties and those of o-benzoylsalicyl- amide (Zoc. c'it.). N=5.54-. C',,H,,O,N requires K = 5.45 per cent.ABSORPTION SPECTRA AND OPTICAL ROTATORY POWER. 199 Disdicykamide, C,H,<OH CO*NH*CO>, HO 4. Disalicylamids was prepared by boiling finely-powdered 0-s Jicyl- salicylamide with fifty times its weight of water for fifteen minutes, when it was obtained as a very bulky, white, fibrous mass melting at 200' ; this crystallised from alcohol in yellow needles melting at 203', the properties of which agree in all respects with those ascribed to disalicylarnide by Schulerud and by G.Colin (Zoc. cit.). Disalicylamide is sparingly soluble in hot glacial acetic acid, but prolonged boiling converts it into the readily soluble O-salicylsalicyl- amide. One gram of disalicylamide was completely dissolved by 1 0 grams of acetic acid after thirty minutes' boiling; the mixture of the isomerides obtained by cooling and precipitating with water contained 66 per cent. of 0-salicylsalicylsmide. Disalicylamide is dissollred without change by cold, strong, sulphuric acid; it is decomposed into salicylainide and salicylic acid by heating it with strong aqueous ammonia in a sealed tribe at 115' for four hours. Dibenxoylclisa Zicylamide, <CO*NH.CO>, 4, is obtained in 4 O*Bz Bz-0 70 per cent. yield by pyritiine benzoylation of disalicylamide at - 15'. 0 2608 gave 7.0 C.C. nitrogen at 23" and 770 mm. N = 3.07. 0.3006 ,, 8.0 ,, ,, 20' ,, 771 mm. N=3.09. C,,H,,O,N requires N = 3:Ol per cent. The description of this compound already given (Zoc. cit.) must be amended in so far as it yields disalicylamide on decompositiotl by sul- phuric acid or sodium hydroxide. ORGANIC LABORATORY, UNIVEIWTY OF L r v e ~ ~ o o ~ .

ISSN:0368-1645    

DOI:10.1039/CT9079100196

出版商:RSC    

年代:1907

数据来源: RSC