Bante 
ee N 
pat. “113 to 114°, Oe ere ete ae differences in the 
"preparations ‘taken first for identical bodies, in those Or: the acti 
inactive preparations. . . anes 
In order to: elucidate these relations Wallach undertdod some 
} : 
> LJ 
unsaturated monovalent alcohol results which passes over ae the aula 
valent alcohol by reduction. 
demonstrated anew that not ‘always unsaturated glycols may be redieod ‘evenly. 
saturated glycols in presence of a colloidal metal. At any rate, the formation 
tetrahydrocarveol is a new proof for the fact that in pinol hydrate one hydroxyl 
linked in position 2. Another fact observed by Wallach in the behaviour of pi 
hydrate was apt to raise doubts as to the correct position in pinol hydrate of b 
the hydroxyl groups. When, namely, i-dihydropinol hydrate, m.p. 139°, was tre 
with acetic acid saturated with hydrobromic acid, there is formed, either at once 
after some standing, terpinene dihydrobromide, m.p. 58°. The same dinydrobrom 
results from active dihydropinol hydrate. The course of both reactions is illustrated 
by the following formula: — a eae 
‘o OH ee ah | 
ae CHs- ae fo. 
H oh KOH SF FL cf OS HC 
iOS NR Kee - 4 cm 
Pinol hydrate. Intermediate product. — Tetrahydrocarveol. 5 : 
OH 
| CH ; he vat , 
| ey : pad | CH; , “Sanaa 
HC eek OR > — —> HsC- a We Brides 
‘CH; CHsg | ie ec 
Dihydropinol hydrate. Terpinolene. Tonia cierto 
Menthane- diol-2,8 from ‘pitiedeacaneent does not show this reaction, “neither 
it observed when dihydropinol hydrate was treated with acetic acid + yataetl ae 
by the formation of a mixture of dihydrochlorides which generally show. 2 a very 
melting point. TA. 
Wallach found furthermore that from the last mother signs f from ay crysta 
from dihydrocarveol. Since menthane-2, &- diol contains ceva as 
atoms and hence must be able to exist in several stereoisomeric forms, 
1) Liebig’s Annalen 892 (1912), 60; Report October 1912, 114.5 
