— n6 — 



Similar experiments were made with succinic acid, citric acid, 

 phthalic acid, and camphoric acid, when the same results were obtained. 

 The co-operation of the free acids in the dehydration process also 

 explains why tartaric acid does not dehydrate menthol. As tartaric 

 acid itself when heated changes considerably, it can no longer act on 

 the ester formed. 



Dry distillation of the sodium, barium, or calcium salts of the acid 

 esters yielded also menthene, in addition to a small quantity of menthol. 



M. Konowaloff 1 ) describes some nitrogen compounds of the 

 menthane-series. Men thane, produced by reduction of menthyl- 

 bromide with zinc and hydrochloric acid in alcoholic solution (boiling 

 point 169,5° to 1 70°, d^ 0,7929, n D2 io 1,43757) can be nitrated 

 with dilute nitric acid both in open vessels and in closed tubes. The 

 nitration-product examined up to the present, mononitromenthane 



(CH 3 ) 2 C(N0 2 )CH( >CH-CH 3 





(boiling point 135° to 137°, d^ 0,9871, n D22 ° 1,46241) can be 

 reduced with tin and hydrochloric acid to the corresponding menthyl- 

 amine (boiling point 199° to 200°, d 2 ^ 0,8451). 



Sesquiterpenes. Oswald Schreiner 2 ) has in two further 

 publications completed his monograph of the sesquiterpenes. It would 

 take us too long even were we only to enumerate here the numerous 

 representatives of this class of bodies. We will only mention that 

 Schreiner reports on no less than sixty different sesquiterpenes, of 

 which, as the author already points out in his introduction, no doubt 

 many are identic, or mixtures of several isomerides. 



Terpenes (as Ladenburg 3 ) and Kriewitz 4 ) have shown) combine 

 with paraformaldehyde into additional compounds of an alcoholic 

 character. According to examinations made by P. Genvresse 5 ), the 

 reaction with sesquiterpenes proceeds in the same manner, though 

 with greater difficulty and with smaller yield. By heating the com- 

 ponents to 180° under pressure, they combine into compounds of 

 the composition C 16 H 26 0. The corresponding derivative of caryo- 

 phyllene represents a liquid boiling at 177° to 178° (15 mm. pressure). 



*) Journ. russ. phys.-chem. Ges. 36 (1904), 237. According to Chem. Centralbl. 

 1904, I, 1516. 



2 ) Pharmaceut. Review 22 (1904), 101, 146. 



3 ) Berl. Berichte 31 (1898), 289. 



4 ) Berl. Berichte 32 (1899), 57, Report April 1899, 49. 

 6 ) Compt. rend. 138 (1904), 1228. 



