154 Report of Schimmel § Co. April/October 1917. 



94.5 to 95.5°. When ^-J'-campholenic acid is oxidized with dilute alcoholic perman- 

 ganate solution one obtains i,i,£-trimethylciycfopentanone-3 (VIII), a liquid smelling of 

 camphor and peppermint and boiling at 167 to 169° (760 mm.). The oxime melts at 

 105 to 105.5° and smells of camphoroxime; the semicarbazone at 221.5 to 222°. 

 Noyes 1 ) had already prepared i,i ;/ 5-trimethy%cZopentanone from a-hydroxydihydro- 

 lauronolic acid and from a,/?,/?-trimethyladipic acid. 



Isoteresantalic acid.— Years ago already, a solid crystalline acid, namely teresantalic 

 acid, was discovered in the- saponification liquor of East Indian sandalwood. While 

 its qualities and reactions have been carefully studied by von Soden and Miiller, 

 Semmler 2 ) and his collaborators devoted themselves to clearing up its constitution. 

 H. Rupe and W. Tomi 3 ) were especially interested in this compound because it is so 

 easy to obtain and shows very strong rotation, so they regarded it as a most welcome 

 test material for their investigations on the correlation between constitution and rotatory 

 power. They intended to split up this acid systematically down to simple ring systems, 

 in order to study the alterations of the optical rotation which would ensue from these 

 proceedings. 



Hydrochloric acid acts on teresantalic acid in such a manner that hydrochloro- 

 teresantalic acid, an addition product, is formed which by means of alkali can be 

 converted into the lactone of the hydroxydihydroteresantalic acid. The authors then 

 intended to split off hydrochloric acid from the above-mentioned teresantalic acid 

 compound, in order to arrive at an unsaturated acid. However, the compound in 

 question proved to be an unsuitable starting material because it was too easily deprived 

 of its carboxyle group, A far more suitable raw material was found in the methyl- 

 ester of the acid which they obtained from the reaction between teresantalic acid ester 

 (produced from the acid by means of dimethylsulphate and alkali) and hydrochloric 

 acid. The next step, splitting off hydrochloric acid, was only possible by heating with 

 aniline; they thus obtained the ester of a perfectly saturated acid, an isomeride of 

 teresantalic acid. A double bond had not been formed, but rather out of the bicyclical 

 system of hydrochloroteresantalic acid, the tricyclical one of teresantalic acid had 

 been rebuilt. The new acid to which the authors apply the term "isoteresantalic acid", 

 differs from the old w-teresentalic acid by reason of its very much greater optical 

 rotation and besides by its solubility, the crystal water content of its salts, §c, as the 

 following table demonstrates: — 



n-teresantalic acid iso-teresantalic acid 



melting point 155° melting point 141.5° 



Mdmo (in benzene) — 76.60° [«] D 2oo (in benzene) — 127.58° 



calcium-salt contains Ca-salt contains V 2 m °l- 



l 1 /* mol. of water. of water. 



It is quite impossible that both acids should be structural isomerides; on the 

 contrary, it seems more likely that the isomerism depends on an alteration in the 

 position in space of the carboxyle group. 



When teresantalic acid methylester is treated with hydrochloric acid, two isomeric 

 hydrochloric esters are formed, a solid, well-crystallizing a-compound (melting point 68°), 

 and a liquid ^-compound. 



!) Berl. BericJde 33 (1900), 54. — 2 ) Comp. Report Oktober 1907, 87; April 1908, 93; October 1910, 129; 

 April 1911, 105. — 3 ) Berl. Berichte 49 (1916), 2563. 



