OPTICAL ACTIVITY OF DERIVATIVES OF RORNTLAMINE. 1149 CXiTIII.--hhj21e?2Ci? Of C!I% UI2SCtt?l,lY6tCd OPb the Optical Act i d y of Certain Derivcc.t iws of Bo ~r~ylccnzirze. Ey MARTIN ONBLOW FORSTER, Ph.D., D.Sc. As a result of investigating certain alkyl derivatives of bornylamine (Forster, this vol., p. 334), it was found that, although the specific rotatory power of the monslkyl derivatives considerably exceeds t h a t of the original base, the optical activity of symmetrical clialkyl deriva- tives npproxiniates very closely to that of bornylamine itself. Ethyl- bornylnmine, for instance, has the specific rotatory power [ a ] , + 90.3O in benzene, but dimethylbornylniniue has [a]1, + 59*Go, the specific rotation of bornylnmine being [.ID + 57.1'. It appears, therefore, that the symmetrical replacement of both atoms of miinic hydrogen, in- volving comparatively slight change i n the disposition of nitrogen with regard t o asymmetric carbon, produces a correspondingly small increase in rotatory power, and i t became of interest to ascertain whether bornylamine derivatives of the type C,,H,,*N:CHR would exhibit the optical properties of didkylbornylarnines, or whether a vor,.1,x xv. 4 H1150 FORSTER : INFLUENCE OF AN UNSATURATED LINKING ON THE disturbing influence would be exerted by the presence of an unsatur- ated linking. Attempts mere niade to obtain subst.ances of the nature indicated by condensing bornylarnine with acetaldehyde and propaldehyde, but nlthough combination occurs very readily in each case, the products are ill-defined oils which boil over a range of several degrees.Atten- tion was therefore devoted to the condensation products of bornyl- amino with various aromatic aldehydes, and in the following table a corn parigon is made between the optical activity of each derivative and that of the original base : Dorny lmiiiic ............................ Heiizy lidencbnl.iiylnnliiit! ............. O r t l ~ o ~ ~ i t r o b c n z y l i ~ ~ c ~ i ~ l ~ ~ ~ ~ ~ ~ I n n ~ i ~ ~ ~ . 1'iLranit r o b e ~ ~ z ~ l i d e ~ ~ e l ~ o r ~ i ~ l a ~ l ~ i ~ i t ~ . . Ortlioliydrosyl bcnzyliileneloriiy1- niii in e .............................. Pnra'ty tl m x y lhcn zylit 1 eiirborn y 1 - aiiiiiie .................................. [ ulo in a1 coli 01. [ AllD in a1co1101. It is evident from these resnlts that no relation, similar t o that connecting bOrJlSlmhe with its dinlkyl cornpoiinds, exists between the primary base and its aromatic aldehyde deyivntives. That the difference between the types C,,I€,~*N:CRR and C,,H,:*NX, must be ascribed to the presence of an ethylenic linking, appears from the following comparison of benzylidene compounds with the corresponding benzyl derivatives : Henzylborn ylnnline .....................Bciizylidenebornyl:,~~iine ............. OrthonitrobenzylL~onlylan~ine ....... Parmlitrobenzylborn ylnnline ......... Orthoiii trobenzylidcneborliylnniinc. l'arsnitrobciizylidencbo~nylnmine . [ aID in bcnzciie. Difference. [ a ] D in nlcohol. Difference. -- 13'1" - 52 '6 - 15.1 According t o these data, a noticeable diminution in rotatory powei attends the transition from a benzyl derivative of this.series t o the corresponding benzylidene compound, and it seems highly probable that an ethylenic linking in the neighbourhood of an asymmetric carbonOPTICAL ACTIVITY OF DERIVATIVES OF BORNYLAMINE. 1151 atom is capable of exerting a perceptible influence on the optical activity t o which the asymmetry of that carbon atom gives rise (compare Haller and Muller, Coitjpt. rend., 1899, 128, 1370). It is also noteworthy that the difference in rotatory power between paranitrobenzylbornylarnine and paranitrobenzylidenebornylamine approaches closely to the corresponding difference bet ween benzyl- bornylamine and benzylidenebornylarine, but is quite unlike that between the ortho-derivatives.This is a fresh instance of closer re- semblance to the parent compound on the part of a para- than of an ortho-derivative (compare this vol., p. 930), and another case is furnished by the nitrobenzylidenebornylamines, of which the para- compound has a molecular rotation almost identical with that of benzylidenebornylarine, but differing most widely from the molecular rotation of the ortho-derivative. There is one point of chemical interest in connection with benzyl- idenebornylamine of which brief mention has been already made (Zoc. cit.). When this base is heated with methylic iodide in a sealed tube, a crystalline additive compound is produced, which, under the influence of water, is resolved into beuzaldehy do and methylbornylamine hydriodide according to the equation C'I,H,~~N(CH3)I~OH~C~H,+H,O=C1,H5*CHO+Cl,Hl~~NH*CH3,I~I. *The usual dificulty of preparing in quantity the monomethyl de- rivative of a primary base has been overcoiiie by this means in the case of bornylamine, but the reaction does not seem to be general, and is probably confined to saturated bases.Benzylidene-P-naphthylamine, for instance, when heated with methylic iodide at 130° and then extracted with ethylic .acetate, yields trimethylnaphthylammonium iodide ; benzylidenephenylhydrazone gives rise to dimethylaniline and a malachite-green. The behaviour of benzylidenebornylamine towards methylic iodide is very similar to that of benzylideneaniline towards acetic chloride, the additive compound froin which yields acetanilide, benzaldehyde, and hydrochloric acid on hydrolysis ; the description of this change (Garzarolli-Thurnlackh, Ber., 1893,32, 2277) appeared simultaneously with the brief notice of benzylidenebornylamine methiodide (this Ex P ERINENT AL.VOI., p. 936). The compound obtained by the union of boriiylamine with benz- aldehyde was described by Griepenkerl as a colourless oil (AnnuZen, 1S93, 269, 353). It has been shown, however, that the method at that time employed for preparing bornylamine gives rise to a mixture 4 ~ 21152 FORSTER : INFLUENCE OF AN UNSATURATED LINKING ON THE of two isomerides (Forster, Trans., 1898, 73, 386); i f thew are separated from one another before treatment with benzaldehyde, the benzylidene derivative of the dextrorotatory base is found to be cryst 11 line.25 grams of bornylsmine were treated with 17 grams of benz- aldehyde, which dissolved the base aid became warm, yielding ,z turbid, oily liquid ; this was heated on the water-bath during some minutes, and aftermnrds cooled with ice, when it rapidly solidified t o a hard, crystalline cake. The product was then fnsed beneath a sinall quantity of hot alcohol, and rapidly cooled, the colourless crjstnls thus obtained being collected with the aid of a piimp and finally recrystallised from alcohol, which deposits bellzylidenebornylamine iu rosettes of long, lustrous needles. It melts a t 58-59'. 0.1709 gave 0.5279 CO, and 0.1509 H,O. 0.303s ,, 16.2 C.C. moist nitrogen a t 17" and $71 mm. N = 6.28. C: = 84.34 ; H = 9.81. C17H2,N requires C = 84.64 ; H = 9.54 ; N = 5.S1 per cent.A solution containing 0.5013 gram in 25 C.C. of benzene at 30' gave a, + 1' 6' in a 2-clcm. tube, whence the specific rotatory power [ aID + 27.4'; 05127 gram dissolved in 25 C.C. of absolute alcohol at 19O, gave a, + 2' 34', corresponding to [a],, + 68.6'. Benzylidenebornylamine does not combine with hydrogon cyanide. It forms a clear solution in cold, concentmted liydrochloric acid, and is precipitated from the liquid by alkalis, but if the acid solution is boiled during a few minutes, benzaldehyde is regeneratecl, and then alkalis precipitate bornylamine. The platinochlo~itle separates almost immediately when platinic chloride, dissolved in alcohol, is added to an alcoholic solution of the base ; i t forms lustrous, transparent, six-sided plates, and decomposes at 245'.0.2029 gave 0.0446 Pt. Pt = 31.SS. (C17H2,N),,H,PtCl, requires Pt = 2 1 *SO per cent. The nLethiocZicle was prepared by heating 4.3 grams of benzylidene- bornylamine with 15 grams of methylic .iodide in a sealed tube at 120-150' during 2 hours. The contents of the tube remain liquid at 30°, below which temperature crystals slowly separate ; the product is t4reated with ether, filtered, and washed with ether, 5.7 grams of the salt being obtained in this way. The methiodide crystallises in pale yellow plates, and melts a t about 2 1 5 O , forming a, deep red liquid which evolves gas. 0.1698 gave 0.1049 AgT. I= 33.36. C,7H,3X,CH31 requires I = 33.16 per cent.OPTICAL ACTIVITY OF DERIVATIVE8 OF BORNYLAMINE. 1152 The methiodide frequently melts indefinitely, and contains proportions of iodine which differ considerably from those required by theory; a specimen decomposing at about 200' contained 30.5 per cent.of iodine, the proportion of which mas increased by recrystallisation from methylic iodide. If the methiodide is rccrystallised from solvents containing water, dissociation occurs, and meth ylbornylsmine hydriodide is produced. For instance, a solution containing 0.2527 gram in 25 C.C. of alcohol gave the specific rotatory power [.IU + 21.8" ; in the case of complete dissociation, [.IL, + 32.3". I n order to prepare metl~yl~ornylamine from benzylidenebornyl- nmine, the methiodide is heated with 5 parts by weight of ethylic acetate in a reflus apparatus during half an hour ; the solvent is for the greater part removed by distillation, and the crystalline residue, when filtered from the solution of benzaldehyde in ethylic acetate, is recrystallised from water.~letliylboimylsmine hydriodide obtained in this manner melts a t %lo, itnd has [ a ] , + 26.6' in a 1 per cent. solution in absolute alcohol. Action of I~?~ei~~Z~~llclraxilze o n ne?z~~Zide?zebos.)z~~(~~}~~ne.-Benzy lidene- bornylamine was mixed with 1 mol. of phenylhydrazine, forming a stiff pqste which rapidly became hard; when heated on the water- bath, the mixture did not melt, as would have been the case if no combination had occurred, bat became red, and smelled of bornyi- amine. After digesting with cold, dilute hydrochloric acid, the undissolved portion was collected and identified with benzylidene- phenylhydrazine, whilst the filtrate, rendered alkaline with caustic soda, yielded bornylamine.When eqna 1 quantities of born y lamine and or t honi t ro benzaldeh y de are intimately mixed, a viscous, turbid oil is produced, which rapidly becomes crystalline. Orthonitrobenzylidenebomylamine separates from dcohol in lustrous, colourless plates and melts at 71"; it becomes bright yellow, and finally dark brown, on exposure to light. 0*1891 gave 0.4946 CO, and 0.1274 H,O. C17H,,0,N, requires C = 71 *32 ; I3 = 7.68 per cent. A solution containing 0*6010 gram in 25 C.C. of benzene at 2 3 O gave aD + l o 40' in a 2-dcm. tube, whence [u],, +41*63; 0*5080 gram dissolved in 25 C.C. of absolute alcohol a t 33" gave aD +21' in a 3-dcm. tube, corresponding to [.ID + 8.6'. C= 71-33 ; H= 7-49,1154 OPTICAL ACTIVITY OF DERIVATIVBS OP kORRYLAMIl?$ Pccl.anitl.obenxyZidenebornylamine, C,,Hli *N: CH C,H;NO,.Six grams of bornylamine were mixed with the same weight of paranitrobeazaldehyde, and heated at 80" until a homogeneous product was obtained ; when cold, the turbid, viscous liqiiid rapidly solidified on being stirred with a glass rod. Pnranitrobenzylidenebornylamine separates from light petroleum in large, yellow, transparent crystals ; it melts at 75'. 0.1244 gave 0.3247 CO, and 0.0876 H,O. C = 71.18 ; H = 7.S2. 0.2266 ,, 20.5 C.C. moist nitrogen at 35" and 769 mm. N = 10.21. C17€Iz20zN2 requires C = 71-32 ; H = 7.68 ; N = 9.79 per cent. A solution containing 0.4069 gram in 25 C.C. of benzene at 15" gave aD +45' in a 2-dcm.tube, whence [ u ] ~ +23.0°; 0.4487 gram, dissolved in 25 C.C. of absolute alcohol a t 3So, gave a, + 1" 51' in a 2-cicm. tube, corresponding to [ + 51.5'. Or tholq clroxg be nxg Zidene bos.?&ntine, Cloll 17 N : C H C,H, OH. When bornylamine (4 parts) is dissolved in salicylaldehyde (3 parts), considerable rise of temperature takes place, and a turbid, bright yellow oil is produced, which solidifies after several days. Ortho- hydroxybenzylidenebornylamine crystallises from light petroleum in bright yellow, transparent prisms and melts at 63"; it dissolves very readily in alcohol, light petroleum, and ethylic acetate. 0.2369 gave 0.6894 CO, and 0.1913 H,O, A solution containing 0.4577 gram in 25 C.C. of absolute rtlcohol at C=70*36 ; H=8-97. CI7H,,ON requires C = 79.37 ; H = 8.95 per cent. 23", gave uD + 4" 23' in a 2-dcm. tube, whence [.ID + 112.3'. P ~ ~ c ~ ~ ~ ? / d r o x y b e n ~ y Z ~ ~ ~ n e b o r ~ ~ ~ Z c 6 ? ~ t ~ ? ~ e , Clo~Il,*N : CH @ C,H, * 011. Bornylamine mas intimately mixed with parnhydroxybenzaldehyde in molecular proportion, the stiff paste thus produced being heated on the water-bath until it solidified. The pnrahydroxy-compound, which is colourless, crystallises from ethylic acetate in lustrous, square, transparent plates, and melts at 162"; it dissolves in hot benzene, but is very sparingly soluble in the cold medium. 0.1510 gave 0.4376 CO, and 0.1222 H,O. C = 79.04 ; H = 8-99. C17H2,N0 requires C = 79.37 j H= 8-96 per cent,INTERACTION OF SODIUM HYDROXIDE AND BENZALDEHYDE. 1155 A solution containing 0.5054 gram in 35 C.C. of absolute alcohol at The snisylideiie and cuiuinylidene derivatives are oils, and were not 15" gave uD + 4' 30' in a 3-dcm. tube, whence [u],, + 107*1'. further investigated.