— 93 — 
systems. At the same time, the reaction does not always pass off 
smoothly and m:iiformly, for the more the isoxime employed is inclined 
to ring-disruption (when, as is well known, fatty amido acids are formed), 
the smaller is the yield of non-oxygenous basic products. But moreover, 
there occur on reduction also oxygenous bases, i. e. alkamines, and 
that, in the case of higher cyclic systems, in considerable quantity. 
Whether with these only the reduction of the CO -group into a CHOH- 
group has taken place, or simultaneously also ring- disruption with for- 
mation of aliphatic amido alcohols, has not yet been definitely decided 
for all cases. 
But in any case so much is certain, that this reduction supplies a 
means for obtaining the higher ring-homologues of piperidine, by which 
the doctrine of the nitrogenous ring-systems is enlarged in a welcome 
manner. For, next to the already known types tri- and tetramethyl- 
eneimine, as also the pentamethyleneimine or piperidine obtainable 
from a-pyrrolidone, there are now also hexamethyleneimine (CHglgNH 
and heptamethyleneimine (C H2)7N H, of which the former can be obtained 
from cyclohexanoneisoxime, and the latter from the isoxime of suberone. 
Just as dihydroisophorone or dihydroisophorol can be converted 
into a-cyclogeraniolene and with the help of the latter into trimethyl 
cyclohexanone there can also be obtained (as Wallach has recently 
found 2) from methyl- 1 -cyclohexanone-3 from pulegone, a cyclomethyl 
hexenone, which differs from Knoevenagel's wxll- known methyl 
either by the position of the ethylene linking, or by that of the carbonyl. 
The alcohol formed by reduction from methyl hexanone yields, 
when heated with zinc chloride, a methyl cyclohexene (tetrahydrotoluene) 
which, like a-cyclogeraniolene, forms a difficultly soluble nitrosate. On 
being heated with sodium methylate, the latter yields a liquid methyl 
cyclohexenoneoxime, which can be split up by dilute sulphuric acid. 
The cyclomethylhexenone thereby formed boils at 179° to 181°, and 
its semicarbazone melts at 207° to 208^; it therefore certainly differs 
from the ketone of the above-mentioned constitution. 
As was pointed out some few years ago by Rabe^), aceto-acetic ester, 
under the influence of sodium ethylate, is attached to a, ^-unsaturated 
^) Compare Report October 1902, 86. 
Berliner Berichte 35 (1902), 2822. — Nachrichten der Kgl. Ges. d. Wiss. 
zu Gottingen 1902, 297. 
^) Berliner Berichte 31 (1898), 1896. 
cyclohexenone 
H3C . C : CH . CO 
CH2 • CH2 • C 
