134 



Report of Schimmel $ Co. 1922. 



which hitherto was not quite fully established. By condensing the ethyl ester of pinonic 

 acid with chloroacetic ester according to the method devised by Darzens 1 ) the authors 

 obtained the corresponding glycidic dicarboxylic ester and thence by saponification the 

 acid itself (II; m. p. 128° with evolution of carbon dioxide). When this acid was heated 

 to 230° it splitted off carbon dioxide and passed over into homopinocamphoraldehydic 

 acid (III; b. p. 130 to 140° [3 mm.]; semicarbazone, m. p. 193 to 194°) which on oxidation 

 with permanganate yielded homopinocamphoric acid (IV; diethyl ester, b.p. 130° [1 mm.]). 

 This acid was best transformed into pinocamphone (V) by the method of W. Dieckmann 2 ), 



CH S 



I 



HC 

 HC 2 



C(CH 3 ) 2 

 CH 



CHCOOH 



COOH 

 CH 2 



COOH 



HC 



H 2 C 



(II) Glycidic dicarboxylic acid 

 from pinonic acid. 



CH 3 

 I 

 CH 



COOH 

 COC 



C(CH 3 ) 2 



CH 3 

 I 

 CH 



CH 2 



HC 



<^ 



s-i. 





^C(CH 3 ) 2 



H 2 C 



"\^ 



'l0§ 



CH 



(III) Homopinocamphor- 

 aldehydic acid. 



CO 



CH 2 



CH 



(IV) Homopinocamphoric acid. 



CH 



(V) Pinocamphone. 



by condensation of the diethyl ester of the (IV), in xylene solution, with sodium. The 

 ketonic acid ester formed primarily was saponified, with formation of pinocamphone, 

 by boiling with a 15 per cent, hydrochloric acid. The semicarbazone and the oxime 

 of the dj-pinocamphone thus obtained were identical (as was proved by the melting- 

 point of the pure substance and of the mixture) with the corresponding preparations 

 of Wallach 3 ) resulting from a ^/-pinocamphone from nitrosopinene by treatment with 

 zinc and acetic acid. Since pinocamphone may be transformed into pinylamine and 

 «-pinene by means of the reactions described already by the authors 4 ), an uninterrupted 

 way is given for the partial synthesis of a-pinene from «-pinonic acid. 



Hitherto it has been generally taken for granted that on addition of dry hydrogen 

 chloride to pinene always pinene hydrochloride = bornyl chloride (I) is formed. 

 O. Aschan 5 ) proved this assumption to be incorrect, as the isomeric liquid, tertiary 

 pinene hydrochloride is formed in this reaction. This compound, stable only at a 

 temperature below — 10°, partly splits off hydrogen chloride on treatment with aniline 

 and yields pinene rotating in the same sense as the starting material. When the tertiary 

 pinene hydrochloride is removed from the freezing mixture, it rises in temperature up 





!) Compt. rend. 139 (1904), 1214. 

 — *) Cf. Bericht (Germ, ed.) 1921, 106. 

 Chem. Zentralbl. 1921, III. 629. 



*) Liebig's Annalen 317 (1901), 27. — J ) Ibidem 304.(1898), 287. 

 - B ) Vetenskaps Akad. Forhand. 67, part A. 1914, No. 1. As per 



