— 97 — 
In connection with the foregoing, menthone, tetrahydrocarvone and 
pentanone, were also submitted to condensation, and the compounds 
then formed were examined in detail. 
Methyl hexanone. For a long time it had been accepted as 
a fact that the acid H^g formed on oxidation of both menthone 
and pulegone, and also of the latter's product of decomposition, 
/?-methyl hexanone, was /5-methyl adipic acid, until Markownikow^) 
expressed a doubt on this point, and stated that he had obtained 
a-methyl adipic acid from ^-methyl hexanone, using nitric acid as 
oxidizing-agent. This statement has since been checked by Bouveault 
and Tetry^), but they found that Markownikow had fallen into 
an error, and that, even when the oxidation is carried out with nitric 
acid, only yS-methyl adipic acid is formed from /?-methyl hexanone. 
This result has recently been confirmed by N. Speranski's^) 
work, w^ho compared the acids C^HjgO^ from menthone, pulegone, 
and ^-methyl hexanone, produced from these bodies by means of 
the calcium salt, the corresponding methyl pentanones, and condensed 
the latter with benzaldehyde. In every case the same dibenzylidene 
methyl pentanone of the melting point 150^ was obtained. a-Methyl 
pentanone, on the contrary, yields a monobenzylidene compound 
melting at 123 — 124°. This shows that on oxidation of menthone, 
pulegone, and /?-methyl hexanone, the same acid, ^-methyl adipic acid, 
is formed. 
Condensation of ^-methyl hexanone with bezaldehyde in the presence 
of sodium ethylate, yields not only benzylidene- and dibenzylidene 
methyl hexanones, but, as L. Tetry^) has established, also a further 
body, which is formed by fixation of one molecule water to the double 
linkage of benzylidene methyl hexanone, and reducing the carbonyl- 
group; it must therefore be designated as oxybenzyl methyl cyclohexanol : 
HgC CHOH 
H3 C . HC< ^ ^ CH . CH(OH) . Cg H5 
C C H2 
^) Berliner Berichte 33 (1900), 1908. 
2) Bull. Soc. chim. III. 25 (1901), 441. 
^) Journ. der russ. phys.-chem. Ges. 34 (1902), 
I, 1 22 1. 
^) Bull. Soc. chim. III. 27 (1902), 302. 
10; after Chem. Centralbl. 1902. 
