— 191 — 



form of beautiful yellow needles, and which may be readily split up into 



^ its constituents by alkalies. He has also observed that coumaric acid 



readily reacts with cineole under heat, forming a double compound from 



which cineole can be immediately regenerated by treatment with soda liquor. 



Acids. 



Camphocarboxylic acid. Camphocarboxylic acid, which is not 

 reducible by the usual methods, may, as discovered by Bredt in colla- 

 boration with Burkheiser and Sandkuhl 1 ), be reduced to borneol carboxylic 

 acid by the electrolytic method. According to Bredt 2 ), camphononic acid 

 behaves similarly, being electrically reducible to camphonolic acid (di- 

 hydrocamphononic acid). The camphononic acid was prepared by the 

 modified Lapworth-and-Lenton method, by preparing free hydroxycamphor- 

 aminic acid from camphanic acid amide, and submitting the sodium salt 

 of this acid to Hofmann's reaction with exactly determined quantities of 

 bromine and alkali. The actual yield averaged from 67 to 69% of the 

 theoretical. 10 grams camphononic acid electrically reduced yielded 

 9 grams reduction -product, containing 4,5 grams camphonololactone, 

 the remainder consisting of cis-trans-camphono\ic acid and of unattacked 

 camphononic acid. The camphonololactone boils at 239,2° and melts bet- 

 ween 160 and 161°. Boiling of the lactone with aqueous baryta solution 

 afforded cis-camphonolate of barium, from which the free hydroxy acid 

 was separated with hydrochloric acid by cooling in ice. This body has 

 no true melting-point, being partly converted, when heated, into the lactone, 

 owing to elimination of water. The cis-£raws-camphonolic acid which was 

 isolated from the reduction-mixture by extraction with soda solution formed 

 bunches of crystals, m. p. 249 to 250°. 



Camphononic acid can be reduced with sodium amalgam without the 

 aid of the electric current, but in this case the reaction is exceedingly 

 slow. With 30 grams acid it required over 50 hours, the amalgam 

 having to be renewed no fewer than seven times, 1000 grams being 

 taken up each time. When the camphonololactone is shaken with saturated 

 hydrobromic acid, /-bromo camphonanic acid (m. p. 146 to 147°) is formed. 

 When the camphonololactone and the cis-trans- camphonolic acid are oxi- 

 dised with nitric acid camphoronic acid is generated. 



^ Bornylene carboxylic acid. A few years ago, Bredt and Sand- 

 Jrahl 3 ) had made the remarkable discovery that hydrobromic acid reacts 

 with bornylene carboxylic acid, giving rise to various bodies according 

 to whether the reaction is carried out in an aqueous or in an anhydrous 



*) Comp. Report October 1906, 135; Report October 1909, 192. 



2 ) Journ. f. prakt. Chem. II. 84 (1911), 786. 



8 ) Liebigs Annalen 366 (1909), 39; Report October 1909, 194. 



