THE CHEMICAL HISTORY OF THE TERPENES 51 



The two following formulae present themselves of which the 

 second is found to be excluded. 



I. ch 2 — CH — CH a 



CMe 2 



CH = CMe— CH 



II. CH— CH CH 2 



I 

 CMe, 



\ 

 CH 2 -CMe=C 



Pinole is an unsaturated compound and the hydrate, sobrerol, 

 when oxidised by permanganate yields a tetrahydric alcohol 

 C 10 H 16 (OH) 4 (m.p. i55 , 5°-i56°) the production of which is in 

 harmony only with Formula I. given above. Sobrerol and the 

 tetrahydric alcohol being respectively 



CH.,— CH — CH, 

 1 

 CMe 2 



OH 

 CH=CMe — CH.OH 



CH, 



-CH- 



-CH, 



CMe 3 

 •OH 

 CH . OH— CMe . OH— CH . OH 



the successive stages of the oxidation of pinole can be easily 

 traced. The glycol Ci H 1(i O(OH) 2 first formed passes into the 

 ketol 



CH,— CH CH, 



CMe 2 



*0. 



CO — CMeOH — CH 



and this ultimately into terpenylic acid and acetic acid. 



The formula for pinole may therefore be regarded as estab- 

 lished on a firm basis, and, with remarkable insight, Wagner 

 perceived that an expression for pinene directly derived from it 

 would be found to supply a satisfactory explanation of the 

 hitherto mysterious behaviour of that hydrocarbon. 



CH 



CH 



CH 



CH, 



CH 



CMe 



