136 REPORT OF SCHIMMEL & Co. APRIL 1914. 
body was exchanged for hydroxyl, while at the same time the ester was saponified, 5 
with evolution of carbonic acid gas. The p-menthanone-3-ol-2 generated during this 
manipulation had b. p. 139° (17 mm.). 
= 
Borneol. For the purpose of differentiating between borneol and isoborneol, 
G. G. Henderson and |. M. Heilbron’), recommend the preparation of the p-nitrobenzoates ~ 
of these alcohols. With this object in view they diluted the alcohol, after dissolving 
it in from 10 to 15 times its weight of pyridine, with the calculated quantity of 
p-nitrobenzoylchloride and heated the solution for some time on the water bath. The 
pyridine is removed by careful manipulation with sulphuric acid (under ice-cooling). 
The p-nitrobenzoate is washed with dilute sulphuric acid and, when dried, is recrystallised 
from alcohol. Bornyl p-nitrobenzoate melts at 137°, iso-bornyl p-nitrobenzoate at 129°. 
The borneol which is recovered from the ester melts at 208°, the csoborneol at 217°. 
Aldehydes. 
Citronellal. With the object of studying the influence of certain groups upon 
the rotation of optically active bodies from the simplest possible example, by employing 
a body with only one asymmetric carbon atom, H. Rupe’) has introduced aliphatic and 
aromatic residues into citronellal, by means of Grignard’s reaction. This method 
affords in the first place secondary alcohols, from which unsaturated hydrocarbons 
can be obtained by the elimination of one molecule of water. It is to be taken into 
account that citronellal occurs in two different modifications, a limonene- and a 
terpinolene-form. An examination of the citronellal derivatives afforded proof of the 
simultaneous presence of both forms, inasmuch as the oxidations of ozone yielded in 
One case acetone peroxide and $-methyladipic acid, and in the other also ketonic 
acids, which latter must be derived from the limonene-form. 
It would lead us too far to discuss the optical behaviour of the numerous citro- 
nellal derivatives and of their decomposition-products, and we will therefore limit 
ourselves to a tabulation of the properties of the alcohols and hydrocarbons described 
by the author: — 
se 
nn oe 
ae 2 ee 2 
| 
Citronellal and afford | B. p: Corresponding hydrocarbon Bp: 
Magnesium methyl bromide | 2, 6-DimethyInonene-) | 103 to 104° | 2,6-Dimethyl-2,7-nonadiene | 61 to 62° 
2-o1-8 (9 mm.) | (9 mm.) 
Magnesium ethyl bromide | 2, 6-Dimethyldecane- 114 to 115° | 2, 6-Dimethyl-2, 8-decadiene 81 to 82° 
2-01-84) (10 mm.) (9 mm.) 
Magnesium propyl bromide | 2, 6-Dimethylundecene- 124° 2,6-Dimethylundecadiene-2,8; 90 to 91° 
| 2-01-8 | (9 mm.) (8 mm.) 
Magnesium allyl bromide | 2,6-Dimethylundecadiene- | 123 to 124° | 2,6-Dimethylundecatriene- - | 94 to 95° 
| 2, 10-o1-8 | (10 mm.) 2,8, 10 (8 mm.) 
Magnesium cyclohexyl _2,6-Dimethyloctene-2-ol-8- | 166 to 167° | 2,6-Dimethyloctadiene-2, 8 142 to 143° 
bromide | cyclohexane-8 (10 mm.) (2, 7)-cyclohexane-8 (9 mm.) 
Magnesium phenyl bromide | 2,6-Dimethyloctene-2-ol-8- 172° 2,6-Dimethyloctadiene-2,7- | 131 to 132° 
| benzene-8 (9 mm.) benzene-8 (9 mm.) 
Magnesium benzyl chloride | 2,6-Dimethylnonene-2-ol-8- | 178 to 179° | 2,6-Dimethy!nonadiene-2,8- | 159 to 160° 
| benzene-9 (9 mm.) benzene-9 (9 mm.) 
Magnesium phenyl ethyl — 2, 6-Dimethyldecene-2-ol-8- 188 to 189° | 2,6-Dimethyldecadiene-2,8- | 163 to 164° 
bromide | benzene-10 | 2mm.) benzene-10 (9 mm.) 
1907, 156. 
1) Proceed. chem. Soc. 29 (1913), 381. — 2) Liebigs Annalen 402 (1914), 149. — 3) Comp. Report October 
4) Comp. Report October 1910, 156. ( aa 
