84 REPORT OF SCHIMMEL & Co. OCTOBER 1915. 
as is the case with y-methylheptenone. The following derivatives were orepavaaes per 4 
methyl:sopropylbutenylcarbinol (b. p. 174 to 177°), ethylisopropylbutenylcarbinol (b. p. 188 — 
to 191°), and ethyl/sopropylbutylcarbinol (b. p. 191 to 195°), As pointed out before, — 
these compounds have an unpleasent smell. 
Trimethylcyclopentenone. When splitting methyl amylenenitrolacetoacetate with 
alkali, Wallach, some years ago, obtained an unsaturated ketone, CsHi20, which had 
to be considered as trimethylcyclopentenone’*). Wallach’) recently repeated this reaction. 
The trimethylcyclopentenone, CgHi,0, forms a ketone of peppermint-like odour and the q 
semicarbazone of which (according to the way of heating) melts at 200 or 210°. It 
was reduced after Skita’s method, when it yielded trimethylcyclopentanone, CsH,,.0O, 
boiling between 164 and 167°; dio. 0.8829; np 1.4336; semicarbazone, m. p. 209°; 
Oxinie,=mi-p.. 105°. 
If treated with sodium ethoxide, instead of aqueous potassa, methyl amylenenitrol- 
acetoacetate shows an entirely different behaviour. It passes over into a yellowish- 
brown body, CyoHisNO;, which is stable in contact with air and almost insoluble in 
organic liquids. 
Isopropylcyclohexanone. A.W. Crossley and W. R. Pratt®) report on the preparation 
of zsopropylcyclohexan-3-one, which might serve as raw material for such terpenes as 
are derived from m-cymene. They treated isopropyldihydroresorcin with phosphorus 
trichloride, when 5-chloro-1-7sopropyl-4*-cyclohexen-3-one resulted, the constitution of 
which was proved by its oxidation to 8-isopropylglutaric acid. The chlorozsopropyl- 
cyclohexenone can, with the aid of sodium, be reduced in moist ethereal solution to 
1-isopropylcyclohexan-3-ol, of which a trans- and a cis-isomeride seem to exist. On 
oxidation with potassium dichromate and sulphuric acid, the alcohol passes into the 
ketone 1-¢sopropylcyclohexan-3-one, a colourless liquid of pungent camphoraceous odour: 
b. p. 119° (62 mm.), 208° at ordinary pressure. The semicarbazone melts at 186 to 
187°, the oxime boils at 155° (37 mm.), and the benzoyl derivative melts at 91 to 92°. 
[sopropylcyclohexanone is but slowly attacked by potassium permanganate, when acetic 
and @-isopropyladipic acids are formed. 
a and 2-Thujamenthone. On reduction of isothujone according to Paal or Skita, 
a saturated body, thujamenthone, is obtained*). A closer investigation of this ketone 
lead Wallach”) to the unexpected result that it is not identical with the thujamenthone 
which had previously been prepared in another way. The two compounds differ con- 
siderably in their behaviour, on account of which Wallach named them e¢- and -thuja- 
menthone. 
‘The long-known «-thujamenthone is obtained by reducing isothujone in alcoholic 
solution with sodium to thujamenthol, which is then oxidized with chromic acid®). In 
order to obtain a reliably pure body, Wallach first oximated the ketone and repeatedly 
recrystallized the oxime. The ketone, regenerated from the oxime (m. p. 97°), was 
treated with semicarbazide; the semicarbazone melted at 185°. The ketone recovered 
from the semicarbazone boiled at 209 to 209,5° (diso 0.8915; np 1.4474). o-Thujamenthol, 
1) J. Rechenberg, /nauguraldissertation, Gottingen 1902, p. 30. — 7) Liebigs Annalen 408 (1915), 202. — 
8) Journ. chem. Soc. 107 (1915), 171. — +4) Comp. Report April 1911, 165. — 5) Liebigs Annalen 408 (1915), 
163. — ®) Comp. Report October 1902, 99. 
