i68 



terpenylic acid. These reactions show the body to be an 8 - hydroxy - 

 carvotanacetone (zl 6 -8-hydroxymenthenone-2), which had al- 

 ready been prepared previously by Rupe and Schlochoff x ). 



CH 3 



I CH 3 



c \ c 



: i i -±: f . I 



H 2 Cv •CH 2 H 2 C \ / CH 2 



CH CH 



HC X>H CH-OH 



I CH Q -C-CH Q 



HX 



CH 2 



CH 

 Pinol hydrate 



CH 8 



I 



C-OH 



CH 3 CH 3 

 8 -Hy droxy-carvotanacetone 



C 



/\ 



CH 3 CH 2 



Carvone 



HO,C 



co- 



-o 



H C — CH — CH, 



(CH 3 \C 



Terpenylic acid 



/?-Pinene. According to Wallach 2 ) the preparation of /?-pinene 

 free from a-pinene is carried out by distilling nopinol-acetic acid with 

 acetic anhydride. In this process there remains in the residue an 

 acid C 13 H 22 5 (m. p. 58 to 59 ) which crystallises out in needles. 

 This acid, of which the gross composition agrees with C u H 18 3 (no- 

 pinol acetic acid) -|- C 2 H 4 2 (acetic acid) was split up, by heating 

 for two hours with caustic soda liquor, into acetic acid and an isomeric 

 nopinol-acetic acid, m. p. 85 to 86°. The latter acid is also differ- 

 entiated from nopinol-acetic acid by the fact that when distilled in a 

 hydrogen current it only yields very few volatile products of decompo- 

 sition. Wallach declines to attempt an explanation of this interesting 

 process of isomerism until further experimental facts are available. 



As it is, therefore, now possible, by treating nopinol-acetic acid 

 with acetic anhydride, to obtain an a-pinene free from /5-pinene, Wallach 

 has also examined a few conversions of this hydrocarbon which had not 

 been more closely investigated up to the present. 



By shaking /?-pinene with 3°/ sulphuric acid for several days a 

 small quantity of terpin hydrate is obtained, the larger part, however, 

 being converted into a hydrocarbon boiling between 170 and 175 . 

 But if, on the other hand, /?-pinene is left to stand for some time 



*) Berl. Berichte 38 (1Q05), 17 19; Report October 1905, 112. 

 2 ) Liebig's Annalen 368 (1909), 6. 



