POSITION OF THE DOUBLE LINKAGE IN PIPERITONE, PART II. 4] 
Experimental. 
It was found that oxidation with both alkaline and 
neutral potassium permanganate resulted in the production 
of the same acids, but in varying proportions, except that 
diosphenol was obtained only by oxidation with the neutral 
salt. On this account, the products of oxidation with 
neutral potassium permanganate only will be described. 
In Part I Communication (Vol. Lv, (1921), p. 139), about 
7 grams of diosphenol were obtained by steam distillation 
from the liquors resulting from the oxidation of 104 ces. 
piperitone. After concentration of the liquid, and acidify- 
ing with dilute sulphuric acid, it was subjected to a vigor- 
ous current of steam to remove the volatile acids, and 
allowed to cool. It was. then repeatedly extracted with 
ether, when upon removal of the solvent, a viscous yellow 
oil was obtained. It was allowed to stand for ten days 
when it became turbid, this phenomenon being assisted by 
cooling in an ice bath. Subsequently on addition of excess 
of ether, a white crystalline solid separated, which was 
removed by filtration, and carefully washed with ether 
until free froin oil. On drying on a porous plate and 
recrystallising from water, about 8 grams of crystalline 
acid were obtained, which melted at 143°5° OC. Titration 
with deci-normal alkali solution showed it to be dibasic, 
and on heating above its melting point it readily split off 
water forming a lactonic acid. 
0°1622 gram on combustion gave 0°3260 gram OO.,, and 
0°1234 gram water. 
Found. Oalculated for CyoH,sOs5 
Carbon A827, 55 °047% 
Hydrogen 8°45 8°25 
Its formula, therefore, being CyoHisO;, it is no doubt 
identical with +-hydroxy-¢-methyl-a-isopropy! adipic acid 
