132 REPORT OF SCHIMMEL & Co. APRIL 1914. 
Sylvestrene. On p.179 of our Report of October 1910, we described a synthesis _ 
of d-sylvestrene carried out by H. W. Perkin. The same author, in conjunction with | 
W.N. Haworth’), has recently also been successful in synthethising 7-sylvestrene. 
The authors took as their starting-point cyclohexanone-3-carboxylic acid, which by 
treating with magnesium methyl iodide they converted into 1-methylcyclohexane-1-ol-3- 
carboxylic acid. By acting upon the last named body with hydrobromic acid they 
obtained 1-bromo-1-methylcyclohexane-3-carboxylic acid and this, when heated with 
pyridine, afforded a mixture of 1-methyl-4'- and 1-methyl-4°-cyclohexene-3-carboxylic 
acid, hydrobromic acid being split off. With the assistance. of the brucine- and 
I-menthylamine salts, d- and /-1-methyl-4°-cyclohexene-3-carboxylic acids were isolated 
from the acid mixture. The dextrorotatory modification (2)-+ 108°) was converted into 
the ethylester which, with magnesium methyliodide, afforded d-4°-m-menthenol-8 (b. p.106 ~ 
to 107° at 20mm.; [«]p — 2,73°). With concentrated hydrochloric acid this alcohol formed 
d-sylvestrene dihydrochloride (m. p. 72°; @p -++- 22,5°), a body which suffered no depression 
of m. p. when mixed with a preparation from Swedish turpentine oil. The sylvestrene 
which was recovered from the dihydrochloride boiled at 175 to 178°; ap + 67,5°. 
The lzvorotatory acid was not yet quite optically pure. It gave 4p — 98,6° and 
afforded /-A°-m-menthenol-8 (b. p. 106 to 108° at 21 mm; «)-+ 1°) from which resulted 
I-sylvestrene dihydrochloride: m.p. 70 to 72°; @p) — 21,8°. J-Sylvestrene boiled between 
176 and 178°; a) — 68,2°. A mixture of equal parts of the two dihydrochlorides had 
m. p. 52°, which is the m.p. of carvestrene (i-sylvestrene)-dihydrochloride. 
l-1-Methyl-4'-cyclohexene-3-carboxylic acid was also prepared in an approximately 
optically pure state (~) —49,7°). It was readily convertible into /-4'-m-menthenol-8 (b. p. 
106 to 108° at 20 mm.; ¢) — 45,9°) which also afforded /-sylvestrene dihydrochloridé 
(although not quite so readily as 4°-menthenol) from which pure /-sylvestrene was obtained. 
On p. 50 of the present Report we describe the properties of a /-sylvestrene 
prepared by us. 
Cadinene. At the meeting of the Moscow Society of Natural Science of 
23 November /6 December 1913, N. Lepeshkin?) stated that cadinene recovered from 
the dihydrochloride by the ordinary methods is not a uniform substance, but con- 
tains, in the form of a by-product, an inactive product of isomerism, which he calls 
isocadinene. Isomerism takes place when the dihydrochloride is heated with glacial 
acetic acid in a sealed tube, and in part also when cadinene is prepared from the 
dihydrochloride with sodium acetate in glacial acetic acid. By treating cadinene 
dihydrochloride with sodium ethylate*), however, Lepeshkin obtained a uniform cadinene. 
On a sesquiterpene related to cadinene, see Oil of Copaiba Balsam, p. 48. 
Alcohols. 28 § 
by 
Ethylamylcarbinol. R.H. Pickard and J. Kenyon‘), in a paper announcing the 
results of their investigations into the dependence of rotation upon chemical con- 
stitution, describe among other things the synthesis of d-ethyl-n-amylcarbinol, which 
was discovered by us at the time in Japanese peppermint oil, and which we have also 
prepared synthetically*). Pickard and Kenyon passed the vapour of a. mixture of 
145 grams n-caproic acid and 180 grams propionic acid through a tube charged with 
1) Journ. chem. Soc. 108 (1913), 2225. — 2) Chem. Ztg. 38 (1914), 276. — *%) Comp. Report October q 
1909, 47. — +*) Journ. chem. Soc. 103 (1913), 1923. — 5) Report Apri) 1912, 102; April 1918, 82. a 
