108 FORSTER : INFRACAMPHOLENIC ACID, AN ISOMERIDE OF X.-Infracampholenic Acid, an Isomeride of Cam- pholytic and isoLauronolic Acids. By MARTIN ONSLOW FORSTER. EIGHTEEN months ago I described the unsaturated nitrile, C9H13N, produced on eliminating hydrogen bromide and carbon monoxide from the anhydride of bromonitrocamphane (Trans., 1899, 75, 1141). At that time it seemed highly probable that the nitrile, and the amideCAMPHOLYTIC AND ISOLAURONOLIC ACIDS. 109 obtained from it on hydrolysis, were derivatives of Walker's cam- pholytic acid, because the amide, although distinct from isolauronol- amide, was converted into that substance by dilute mineral acids. The investigation of the acid derived from the amide is still incom- plete, but the recent appearance of a posthumous paper by Tiemann, in association with Kerschbaum and Tigges, on the two campholytic acids (Ber., 1900, 33, 2935), closely following a communication on the same subject by G.Blanc (Bull. Soc. Chim., 1900, [ iii 3, 23, 695), obliges me to describe briefly the progress which has been made i n the examination of the substance. The nitrile has to be heated with alcoholic potash continuously for several weeks before ammonia ceases to be evolved; there is then obtained the potassium salt of a liquid acid, C,H,,O,, which closely resembles Walker's campholytic acid, forming a viscous oil which boils a t 145' and 239' under pressures of 24 mm. and 758 mm. respectively. &loreover, the substance is optically inactive, and treatment with dilute mineral acids transforms it into isolauronolic acid, differing in no respect from the acid, obtained by the action of aluminium chloride on camphoric anhydride.Here, however, the resemblance to campholytic acid ceases. According t o Walker (Trans., 1893, 63, 498), that substance absorbs a molecular proportion of bromine, yielding the dibromide C,H,,O,Br,, which melts and blackens a t 106-107'. When, however, the new acid is treated with bromine under the conditiofis specified by Walker, two molecular proportions of the halogen are engaged, hydrogen bromide is elimi- nated, and the solid product consists of a tribromocarboxylic acid, C,Hl,0,Br3, which melts to a colourless liquid, and evolves gas, a t 182'. Moreover, the dibromide of the new acid, which can be obtained when bromine is slowly added in quantity scarcely sufficient t o con- vert all the substance into the compound C,H,,O,Br,, is quite distinct from the isomeric dibromide of campholytic acid, because it melts at 125' without blackening.Furthermore, whilst campholytic acid is converted by hydrobromic acid into the hydrobromide, C,Hl,OBr, several attempts, under varying conditions, to obtain a corresponding derivative from the new acid have resulted i n the production of isolauronolic acid. It has now been shown that the new substance is the lower homo- logue of a-campholenic acid, and I propose therefore to call it infracampholenic acid, the prefix '' infra " representing in this sense the converse of '' homo.'' Some months after the discovery of tribromodih y droinfracampholenic acid, and the consequent recognition of the fact that infracampholenic and campholytic acids are distinct, the paper by G.Blanc (Zoc. cit.) was published without any previous intimation that he proposed to110 FORSTER : INFRACAMPHOLENIC ACID, AN ISOMERIDE OF investigate the nitrile with which I was working. On reducing that substance with sodium i n absolute alcohol, Blanc obtained the amine which a-campholenamide yields when oxidised with sodium hypobromite, namely, a-aminocampholene, first described by Blaise and Blanc (BUZZ. Soc. Chim., 1899, [ iii], 21, 976) ; assuming that the nitrile is indeed the nitrile of campholytic acid, this result appeared to confirm the view that campholytic acid is the lower homologue of a-campholenic acid, and Blanc would have expressed its constitution by the formula C1H2* $JH*CO,H CH,* C : CH, I p e 2 7 but for the appearance oT Walker's latest paper on the subject (Trans., 1900, "7, 374).In consequence of this publication, Blanc agreed that campholytic acid is a stereoisomeride of isolauronolic acid, CH,* g*CO,H CH,*CMe2 I yMe 7 and adopting Bouveault's formula for a-campholenic acid, I, repre- sented the constitution of infracampholenic acid by the expression I1 : CH,-$J'H* CH,-CO,H CH,* VH*CO,H CH,*C:CH, CH,*C:CH, Working with Noyes' active campholytic acid, that is t o say, with the acid obtained by the action of nitrous acid on dihydroamino- campholytic acid, Tiemann (Zoc. cit.) arrived a t aa-dimethyltricarb- allylic acid by oxidation with dilute nitric acid, and therefore represents the constitution of campholytic acid by the formula I11 : UH,* yH*CO,H CH =CMe I.I ?Me, - 11. I ?Me, 111. I ?Me, This view is now endorsed by Blanc (Compt. rend., 1900, 131, S03), who has oxidised inactive campholytic acid, derived on this occasion from isolauronolic acid by Walker's process, obtaining also aa-dimethyl- t ricarball y lic acid. In giving expression to this change of view, Blanc does not refer to the result of his experiment with the nitrile of infracampholenic acid, which showed that this acid is the lower homologue of a-campholenic acid ; the formula 111, which, in agreement with Tiemann, he ascribes to campholytic acid, represents the latter substance as the lowerCAMPHOLYTIC AND ISOLAUROKOLIC ACIDS. 111 homologue of a-campholenic acid, the constitution of which is best expressed by Tiemann’s formula, 1H2* QH* CH,*CO,H CH,*FH*CO,H 7% 4 I ?Me, .HXMe CHZCMe In view of the fact, established in this paper, that campholytic and infracampholenic acids are distinct, one of three things follows : Tiemann’s formula for a-campholenic acid is incorrect, Blanc’s re- duction of infracampholenonitrile to a-aminocampholene is misleading, or the expression I11 does not truly represent the structure of campho- lytic acid. Now Tiemann’s formula for a-campholenic acid is based on the production of isoketocamphoric acid, COMe*CMe,*CH(CH,*CO,H),, on oxidation, and appears therefore to be well founded. There is likewise no reason to mistake the conclusion to be drawn from Blanc’s experiment showing that a-campholenic acid is the homo-derivative of infracampholenic acid.There remains, therefore, the third possibility, namely, the invalidity of the formula for campholytic acid advocated by Tiemann and by Blanc. While discussing the constitution of that substance, the last-named investigators do not allude t o the alternative formula, CH= F C0,H CH,*CHMe IV. I ?Me, , from which, by oxidation, aa-dimethyltricarballylic acid might be obtained. Perhaps the drawback which presented itself to them was the conversion of the complex *CMe2*CHMe* into the grouping -CMe,*UH(CO,H)*, a change which is certainly unusual. In view of the present difficulty, however, this formula deserves consideration because the structure of infracampholenic acid would then be re- presented by the expression 111.The following arguments may be brought forward in support of this suggestion. 1, The formula IV, with the qualification already mentioned, accounts for the production of aa-dimethyltricarballylic acid, CH=S-CO,H CO,H vO,H I ?Me2 YMe2 . 2. It represents campholytic acid as an up-unsaturated acid, in 3. It reconciles the facts that infracampholenic acid is distinct from CH,*CHMe - ~H,--CII.CO,H accordance with the results of Walker’s experiments.1 12 FORSTER : INFRACAMPHOLENIC ACID, AN ISOMERIDE OF campholytic acid, and is nevertheless a lower homologue of a-cam- pholenic acid. 4. The representation of infracampholenic acid by the formula 111 explains the production of a tribromo-derivative by direct action of bromine, the a-carbon atom being hydrogenised, and therefore sus- ceptible to the action of bromine.5. The formula IV is more consistent with the behaviour of campho- lytic acid towards bromine than the representation which is given by Tiemann and by Blanc, because dihydroisolauronolic acid, CH,*QH*CO,H CH,*CMe, I p M e 9 can be brominated in the a-position (Perkin, Trans., 1898, 73, 838), and tetramethylenecarboxylic acid, QH,*QH*CO,H CH,*CH, ? readily undergoes the same change (Perkin and Sinclair, Trans., 1892, 61, 42); if therefore, cRmpholytic acid has the structure 111, it might be expected to behave like infracampholenic acid, and give a tribromo- derivative instead of a dibromide. 6. On the lines of Lapworth’s proposal, according to which the production of isolauronolic acid from camphoric acid involves the migration of a methyl group (Trans., 1900, 77, 1057), the conversion of campholytic acid into isolauronolic acid can be explained as follows : CH=C*CO,H Me CH,*CHl!de this scheme is no less plausible than that adopted by Blanc (Compt.rend., 1900, 131, 805 ; Abstr., 2901, 80, i, 11) for the same purpose. Against the propositions made in this paper will be urged the fact that aminodihydrocampholytic acid, CH,*v H-CO,H CH,*CMe*NH, I ?Me2 9 under the influence OF nitrous acid, is more likely to yield a substance having the formula I11 than the alternative compound, IV. This is, prim$ facie, true, but it must be borne in mind that the substituentsCAMPHOLYTIC AND TSOLAURONOLIC ACIDS. 113 in this complex display great mobility, which is shared by the hydrogen atoms.I n the hope of settling definitely the constitution of infracam- pholenic acid, a study of its products of oxidation is being made, and I expect to gain evidence of its structure also by examining the alcohol obtained from aminoinfracampholene, C8H13*NH2, by the action of nitrous acid; the base itself is described in this paper, being readily furnished by inf racampholenamide when treated with sodium hypo- bromite. Before proceeding to the experimental details, I think it is desirable to draw attention to the nomenclature for campholytic and isolauronolic acids adopted by Tiemann’s collaborators in the paper first mentioned (Ber., 1900, 33, 2935). They distinguish these substances, which are perfectly well recognised under the original names, as a- and /3-campho- lytic acids respectively.This distinction seems to be somewhat unfor- tunate. I n the first place, the substance which they propose to call a-campholytic acid, is derived from P-camphoramic acid, whilst a-camphor- amic acid yields, not /3-campholytic acid, but. lauronolic acid. Secondly, it is claimed that the use of these letters illustrates the relationship of the acids to a- and P-campholenic acids ; no evidence is adduced in the paper, however, to shorn that such a relation holds good, and although Blanc’s investigations suggest that /3-campholenic acid is the homo- derivative of isolauronolic acid, the same author has shown that a-campholenic acid is not connected with campholytic acid in a similar manner. I n these circumstances, confusion will be avoided by adher- ence to the original names for campholytic and isolauronolic acids.EXPERINENTAL. Infracmpholenic Acid, C,H,,O,. The readiness with which the amide, C,Hl,* 00 *NH,, is converted into isolauronolamide under the influence of dilute hydrochloric acid renders this agent useless for the purpose of hydrolysis. Attempts have been made under varied conditions to transform the amide into the acid by means of nitrous acid, but on each occasion the unchanged substance was recovered. The only alternative was to use alcoholio potash, and although the action is extremely slow, and involves heating the liquid during several weeks, this method was ultimately adopted. Twenty grams of the purified amide were dissolved in 100 C.C. of alcohol, and heated with 25 grams (3; mols.) of potassium hydroxide dissolved in the minimum quantity of water, until no further evolution of ammonia took place.Hydrolysis was complete after 200 hours, The liquid was then evaporated on the water-bath, and the viscous residue washed two or three times with ether, dissolved in water, and VOL. LXXIX. I114 FORSTER : INFRACAMPHOLENIC ACID, AN ISOMERIDE OF just acidified with cold, dilute, hydrochloric acid, which precipitated a pale brown, viscous oil. This was dissolved at once in ether, washed with water, redissolved in sodium carbonate, and then extracted with ether in order to remove any non-carboxylic impurities. The solution of the sodium salt was exactly neutralised with dilute sulphuric acid, and on removing the precipitated oil with ether, drying the extract with fused sodium sulphate, and afterwards evaporating the solvent on a water-bath, 19 grams of the acid were obtained.The product, which was pale brown and very viscous, mas then distilled under reduced pressure ; various specimens boiled a t 145q 170°, 180°, and 239' under pressures of 24 mm., 60 mm., 105 mm., and 758 mm. respectively, yielding a colourless, or very pale yellow, viscous oil, having a faint, somewhat disagreeable odour. 0*2000 gave 05122 GO, and 0.1630 H,O. C,H,,O, requires C = 70.13 ; H = 9.09 per cent. A 20 per cent. solution in ether is optically inactive, and a 10 per cent. solution of the amide in absolute alcohol is also devoid of activity. The acid has a sp. gr. 1.0146 a t 1 6 O , and a refractive index pNa 1.4660 at 1 9 O .When infracampholenic acid is warmed with dilute sulphuric acid it soon solidifies, yielding isolauronolic acid, which was compared with a specimen obtained from camphoric anhydride; it melts a t the same temperature, and like the acid from this source, is optically inactive. A neutral solution of the ammonium salt gives no precipitate with magnesium sulphate, calcium chloride, or barium chloride, but the mercuric salt forms minute white needles, sparingly soluble in cold water. The copper salt separates immediately as a dark green, crystalline pre- cipitate, whicb dissolves readily in hot alcohol, forming a deep green solution j this deposits nodular aggregates of minute green needles. The lead salt forms a white, flocculent precipitate, soluble in boiling water, from which it crystallises in small, transparent, six-sided plates.The silver salt is soluble in hot water, separating in colour- less crystals which are affected only slowly by light. C = 69.85 ; H = 9-05, Certain salts of infracsmpholenic acid are well defined. Tri6romodihydroinfraca~p~o~~nic Acid, CgH1,O,Br,. I n the first attempts to prepare a dibromide, the conditions pre- scribed by Walker (Zoc. cit.) were observed. Seven grams of bromine dissolved in 20 C.C. of dried carbon disulphide were placed in a wide- mouthed bottle through the stopper of which passed a tap-funnel and a tube containing calcium chloride ; the bottle mas immersed in melt- ing ice in a large, blackened beaker. Five grams of infracampholenicCAMPHOLYTIC AND ISOLAURONOLIC ACIDS.115 acid dissolved in 20 C.C. of dried carbon disulphide were then added slowly through the tap-funnel, the solut?ion of bromine being shaken continuously during the process, and the operation being carried out in a darkened room. Colourless crystals were soon deposited in the bottle, and hydrogen bromide escaped through the calcium chloride tube. After remaining 12 hours in the dark, the solution was de- canted, and the crystals washed with light petroleum; the crude material obtained in this may amounted to 4.5 grams, a further quan- tity being obtained from the mother liquor. The freshly precipitated substance melted a t 178'. It was recrystalIised from hot ethyl acet- ate, in which it dissolves readily, being deposited in aggregates of small, hard needles, which melt to a colourless liquid, evolving gas, a t 182'; the melting point is dependent on the rate a t which the tem- perature rises, and has been observed as high as 187".0.2164 gave 0.2174 CO, and 0,0649 H,O. 0,1725 ,, 0-2465 AgBr. Br=60*80. The operation just described has been repeated many times, and the same result mas obtained in each case. Even when the halogen solution was cooled by a freezing mixture, and the acid added as slowly as possible, in a dark room, hydrogen bromide was evolved after a very short interval, and crystals wore deposited in the bottle when only a small proportion of the material had been added. Increasing the quantity of bromine does not improve the yield of the substance, which rarely exceeded 65 per cent, of the theoretical amount.The tribromide of infracampholenic acid dissolves readily in alcohol, and the cold solution immediately develops with silver nitrate a turbidity which rapidly intensifies to a copious precipitate. It dissolves in aqueous sodium carbonate with liberation of carbon dioxide, form- ing a bromohydrocarbon and an unsaturated acid; if the alkali is added in small quantities amounting in all to one molecular proportion only, nearly two-thirds of the substance remains unchanged. The following experiment was therefore performed. Twenty grams of the finely powdered tribromide were suspended in water, and treated with a cold solution of 21 grams (4 mols.) OF anhydrous sodium carbonate. The substance dissolved almost imme- diately without liberating carbon dioxide, as this was absorbed by the excess of alkali.The turbid solution, after 24 hours, had deposited a heavy, colourless oil, which was removed by means of ether, washed twice with water, and freed from ether on the water-bath; on passing a current of steam through the residue, a bromohydrocarbon was obtained having an agreeable odour. C= 27-40 ; H=3*33. C9H1,0,Br, requires C = 27.48 ; H = 3.33 ; Br = 61.07 per cent. 1 211 6 FORSTER : INFRACAMPHOLENIC ACID, AN ISOMERIDE OF 0.1908 gave 0.1781 AgBr. Br = 39.71. 0.1818 ,, 0.1702 AgBr. Br = 39.83. C,H,,Br requires Br = 42.78 per cent, It is probable that this substance does not represent the initial pro- duct arising from the tribromide by the elimination of carbon dioxide and hydrogen bromide according to the equation : C,H,,O,Br,Na L= C,H,,Br + NaBr + HBr + GO,.Most likely the.hydrocarbon dibromide, C8HI2Br2, is first produced, and undergoes resolution into the bromo-derivative, C,HllBr, and hydrogen bromide during the process of isolation, because the sub- stance extracted by ether is colourless, becoming pale yellow when distilled in steam ; the aqueous residue in the distilling flask contains a considerable amount of hydrobromic acid, and holds some dark brown, non-volatile, tarry matter in suspension. It will be interesting to ascertain the nature of the acid produced along with the hydrocarbon, and steps are being taken in this direc- tion, but unfortunately the substance is resinous, and the only infor- mation concerning it which has been gained so far is the fact that it is unsaturated and contains bromine. Four grams of infracampholenic acid were dissolved in 100 C.C.of dry chloroform, and to the solution, immersed in a good freezing mix- ture, rather less than 4 grams of bromine, dissolved in 50 C.C. of cold chloroform, were slowly added. Owing to the readiness with . which one atom of hydrogen in infracampholenic acid is replaced by bromine, great care was taken to keep the solution in a state of agitation, and the solution of bromine was admitted drop by drop; liberation of hydrogen bromide was thus reduced to a minimum, and only towards the end of the operation did the gas make its appear- ance. Without removing the vessel from the freezing mixture, a current of dry air was aspirated through the pale yellow liquid during one hour, after which interval the solution was allowed to acquire the temperature of the atmosphere.When the chloroform had com- pletely evaporated, a white, butter-like mass remained ; this was drained on porous earthenware, and washed several times with cold petroleum, The snow-white, micro-crystalline powder obtained in this way melts at 117" to a colourless liquid evolving gas ; it dissolves very readily in alcohol and in cold ethyl acetate, but is rather sparingly soluble in boiling petroleum, which deposits it in minute rectangular plates; these melt and evolve gas at 125'.CAMPHOLYTIC AND ISOLAURONOLIC ACIDS. 117 0.2152 gave 0.2653 CO, and 0.0853 H,O. 0*1599 ,, 0,1940 AgBr. Br = 51-62. C = 33-62 ; H = 4.40. C,H,,O,Br, requires C = 34.14 ; H = 4-46 ; Br = 50.95 per cent.The dibromide dissolves immediately in aqueous sodium carbonate, and the turbid solution deposits a bromohydrocarbon on standing. The Arnide of Infraaampholenic Acid. When the extraordinary indifference of inf racampholenamide towards alkaline hydrolytic agents was first observed, an attempt was made to st'udy the oxidation products of the acid by oxidising the amide and hydrolysing the product. Oxidation of Infracampholenamide.--Ten grams of the amide were dissolved in 5000 C.C. of boiling water and rapidly cooled, the temper- ature of the solution being finally reduced to about Oo by immersion in melting ice. Three hundred C.C. of a 2 per cent. solution of potass- ium permanganate were added in small quantities, the colour of the solution being immediately destroyed.The liquid was then treated with 15 grams of potassium carbonate, boiled, filtered, and evaporated to small bulk, when a dark yellow oil separated, and solidified on cooling, After being drained on porous earthenware, washed with a small quantity of cold water, and again drained, the colourless pro duct weighed 8.5 grams. Under these conditions, the amide is oxidised to a dihydroxy-deriva- tive. The substance dissolves very readily in water, forming a solution which is neutral to litmus. Alcohol also dissolves it freely, and ethyl acetate is the most convenient solvent from which to crystallise it, depositing the derivative in prisms containing lH20. A specimen dried in the desiccator was analysed, with the following result : 0.1775 gave 0.3492 CO, and 0.1534 H,O.C =53.65 ; H= 9.60. C,H,lO,N,H,O requires C = 52.68 ; H = 9.27 per cent. In the hydrated condition the substance has no definite melting point, but liquefies at about llOo, when water is liberated. If the crystals deposited by ethyl acetate are powdered finely and dried at 90' until no further loss of water takes place, the substance melts at 170°, without evolving gas, 0.1816 gave 0.3861 CO, and 0.1500 H,O. C=57*99 ; H= 9-17. 0.2218 ,, 14.2 C.C. of nitrogen a t 16.5' and 779 mm. N = 7-63. C,H,,O,N requires C = 57-76 ; H = 9.09 ; N = 7.48 per cent. The oxidised amide is hydrolysed by alcoholic potash much more 0.2073 ,, 0.4415 CO, ,, 0.1694 H,O. C=58*08 ; H=9*08.118 FORSTER : INFRACAMPIIOLENIC ACID, AN ISOMERIDE OF readily than infracampholenamide, but the acid obtained in this way takes the form of a resin, Hydrobromide of Infracampholenamide, C,H,,ONBr.-The amide of infracampholenic acid was dissolved in 48 per cent. hydrobromic acid, and allowed to remain in the desiccator. After some days, clusters of flat, transparent, rhomboidal plates separated. Cold alcohol dis- solves the substance very readily, and it is also soluble in cold water, forming an acid solution ; when potassium permanganate is added to this liquid, the colour is destroyed and bromine set free. The hydro- bromide is insoluble in petroleum, and very sparingly soluble in cold ethyl acetate, but it dissolves readily in the boiling liquid, which deposits it in transparent plates melting a t 144', with vigorous dis- engagement of gas.0.2165 gave 0.1603 AgBr. Br= 31-50. C,HI6ONBr requires Br = 34.1 8 per cent. C9HlGONBr,H',O ,, Br = 31.74 ,, An attempt t o prepare the hydrobromide by dissolving the amide in more concentrated acid (sp. gr. 1.83) resulted in the production of bolauronolamide. The clear solution in the acid deposited lustrous, colourless crystals melting indefinitely between 70' and SO', and yielding isolauronolamide and hydrobromic acid on treatment with water, which first converts the crystals into an oil ; isolauronolamide itself yields similar crystals under the influence of the concentrated acid, the product consisting most likely of an unstable salt. Dibromide of Infrc6ccamphole~ccmicEe, C,HI,ONBr,.-Ten grams of the amide were dissolved in dried chloroform, cooled in a freezing mixture, and treated with 10 grams of bromine (1 mol.) in the same solvent, the halogen being added in small quantities at a time ; the bromine was immediately decolorised, and no hydrogen bromide was liberated.On evaporating the chloroform, colourless crystals were deposited, and the product was filtered from a small quantity of oil, washed with chloroform, and recrystallised from boiling ethyl acetate, which deposited it in white needles melting at 114'. 0.2148 gave 0.2435 AgBr. Br = 48.33. 0.2660 ,, 0.3017 AgBr. Br = 48.26. 0.3321 ,, 13.1 C.C. of nitrogen at 20' and 762 mm. N=447. C,H,,ONBr, requires Br = 51.12 ; N = 4.60 per cent. C9H,50NBr2,H20 ,, Br = 48-34 ; N = 4.23 ,, The dibromide is insoluble in petroleum, but dissolves readily in alcohol, and is very freely soluble in water, forming a neutral solution from which it crystallises in white prisms; the aqueous liquid pre- cipitates silver bromide from the nitrate, but does not liberate iodineCAMPHOLYTIC AND ISOLAURONOLIC ACIDS, 119 from potassium iodide, even when acidified with dilute sulphuric acid.It is indifferent towards a neutral solution of potassium perman- ganate, but in presence of dilute sulphuric acid bromine is liberated, and the permanganate decolorised. Arninoin fi.acamnphoZene, C,H1,*N H,. Ten grams of purified infracampholenamide were finely powdered and suspended in 25 C.C. of water; 10 grams of bromine were then dissolved in 100 C.C. of water containing 10 grams of caustic soda, and added to the amide.On gently warming the liquid, a basic odour became perceptible in a few minutes, and an oil rose to the surface. After about an hour, during which period the liquid was agitated, and at intervals gently heated, the base was extracted with ether, washed several times with water, and after removing the ether on a mater- bath, distilled in an atmosphere of steam. The colourless oil obtained in this manner was collected by ether, dried with solid potash, and freed from ether on the water-bath. The yield amounted to 4 grams, and might possibly be augmented by manipulating smaller quantities of the amide at one time, because an experiment in which 25 grams of material were employed yielded only 9 grams of base. Aminoinfracampholene is a colourless, limpid oil having a pungent, somewhat pleasant odour, and boils a t 158-160' under 754 mm.pressure ; it has a sp. gr. 0.8'770 a t 14", and refractive index pNn 1.4748 at 19". The base absorbs carbon dioxide readily from the air, forming a crystalline carbonate. The hydrochloride is readily soluble in cold water, and crystallises in lustrous leaflets melting a t 213'. The plutinicldoride separates immediately in pale red crystals on adding aqueous platinic chloride to a solution of the hydrochloride in water, It dissolves very freely in hot alcohol, and crystallises in beautiful, lustrous, pale red leaflets. 0.1528 gave 0*0450 Pt. Pt=29*45. (C,H,,N),, H,PtCI, requires P t = 29.48 per cent. The salt darkens at about 200°, and melts to a charred mass The picrate crystallises in clusters of sulphur-yellow needles on 0.2452 gave 33.8 C.C. of nitrogen at 18' and 752 mm. It melts at 2 1 3 O to a deep brown liquid which soon begins to The benxoyl derivative is very readily soluble in ethyl acetate at 238-240O. adding to the base a hot solution of picric acid in alcohol, N = 15.75. C,H,,N,C,H,O,N, requires N = 15-82 per cent. evolve gas.3 20 EASTERFIELD AND ASTON: TUTU. PART I. and in alcohol, crystallising from the latter in rosettes of long, slender prisms melting a t 105' ; it is sparingly soluble in boiling petroleum, from which it separates in lustrous, silky needles which melt also at 105O. 0.1672 gave 0.4631 00, and 0.1225 H,O. C1,HIQON requires C = 75.31 ; H = 7.95 per cent. The carbamide derivative is not precipitated immediately on mix- ing moderately concentrated solutions of the hydrochloride and potassium cyanate, but soon crystallises when the liqyid is heated on the water-bath; i t forms lustrous, white needles melting a t 182'. 0.1658 gave 24-5 C.C. of nitrogen at 1705~ and 756 mm. N = 17.01. C,H,,ON, requires N = 16-66 per cent, The phenykarbamide derivative separates in aggregates of flat, lustrous needles on adding a solution of phenylcarbimide in a mix- ture of ether with petroleum to a solution of the base (1 mol.) i n ether. C=75*54; H=8*14. 0.1831 gave 0-4920 CO, and 0.1357 H,O. The substance crystallises from alcohol in very long, flat, trans- C = 73.28 ; H = 8.23. Cl,H,,0N2 requires C = 73-77 ; H = 8.19 per cent. parent needles and melts a t 180O. ROYAL COLLEQE OF SCIENCE, LONDON, SOUTH KLNSINGTON, S. W.