« 7 
iting the alkaline eShitior, one obtains, on acidulation, an Bee qiticn, through 
Ilation with lead peroxide and sulphuric acid, yields a ketone, fairly soluble in 
"water. Tf active methylcyclohexanone from pulegone is used to start from, the 1,3-methyl- 
Reestzopentaaone is dextrorotatory; dibenzylidene compound, m.p. 149 to 151°, The a 
id dibenzylidene compound of the inactive ketone melts between 155 and 156°. 
= Wallach then describes the transformation of 1,4-methylcyclohexanone into 1 ,3-methyl-_ 
-cyclopentanone. . On brominating the former, a liquid dibromide was obtained, which — 
% teadily dissolved when being shaken with potash lye. Neutral substances, which have 7 
a 
4 
ba med oy 
i £ PO eA ls Sen 
ae" hone ene 
i Ade ie f ah (GS 
Me a +B ws 
at \s — bg ve ae 
Hi) 4 1% 9 By ms ee oa 
odie ht Oe STS Fe aN 
ae AER Cp gan Ua CS 
Bese 
WA 
not been investigated so far, formed as by-products, m. ps. 201 to 203° and 149 to 157°, i a 
respectively. A liquid compound, colouring with ferric chloride, has not been observed. = 
On boiling down the alkaline solution, an acid was obtained which could easily be S % 
s isolated but proved not to be uniform. If heated with lead peroxide and sulphuric — es 
acid, it is converted into i-1,3-methylcyclopentanone; semicarbazone, m. p. = to 186°, . z ee 
_ dibenzylidene compound, m.p. 156 to 157°. : gS 2 
Dimethy]- 1,3-cyclohexanone-5 in glacial acetic acid yields on being Groniiniaedt Ros 
mixture of two dibromides. The «-dibromide melts at 163 to 164°, the 8-dibromide at — 
z : 60 to 61°. The former is sparingly attacked by potash and is formed ‘only in small — 
= quantity. On decomposing the §-dibromide with potash lye and distilling the liquid 
-- with steam, a readily congealing body, CsHi2O2, passes over, m. p. 71 to 72°. i 
= _ aqueous solution colours intensely dark with ferric chloride. It yields with boiling alkali — 
' an acid, CsHi,Os, m. p. 92 to 93°, which is converted into 1 ,3-dimethyleyclopentanone-4 
t by treatment with lead peroxide and sulphuric acid, when carbon dioxide is ever off. ee s 
_Semicarbazone, m.p. 165 to 166°. ee 
i. As primary material for the conversion of trimethyl 1, 3,3- cyclohexanone-5 (dihydro-— 
isophorone) into trimethyl-1,3, 3- cyclopentanone-5, ophistine was used, which was reduced 
to dihydroisophorone wordnet Skita’s method. It easily affords a beautifully crystal- 
lizing dibromide, m. p. 90°. Potassium hydroxide converts it into a compound, CpsHuO., 
readily volatile with steam, m.p. 89 to 90°, which colours violet black with ferric — a 
_ chloride. and acts strongly reducing. On being heated with potash lye, it forms an 
acid, C41... 0), 1m: p. 88 to 89°, which is characterized by an almost insoluble ferric _ a. 
salt. Heating with lead peroxide and sulphuric acid leads to trimethylcyclopentanone, ioe 
db. p. 159.5 to 161°; diso 0.8785; mp 1.4330; semicarbazone, m.p. 171 to 173.59. The 
ai They pd 
shilek ae Fa Se 
‘ketone has a penetrating smell of peppermint. On being oxidized with chromic acid, — 
it yields a keto acid, CsHi,Os, with the same carbon content and the semicarbazone — " “3g 
of which melts between 168 and 169°. a 
E Menthone (methyl-1-isopropyl-4-cyclohexanone-3) can be converted into dihydro- Be 
_camphorphorone (methyl- 1-isopropyl- 3-cyclopentanone-2). Bromination in glacial acetic — ee 
acid leads to a dibromide, m.p. 79 to 80°, which according to Beckmann represents 
al ,4-dibromomenthone. Wallach thinks it more probable that the bromine atoms are 
in 2, 4-position. When the dibromide is shaken with potash lye, a mixture of products, > 
— CroHreO:, forms, which is free from bromine and may be isolated by steam distil- Se 
lation of the mixture. The components (a- and 8-) are separable through fractionated — “Ss 
__ crystallization. The «compound melts between 82 and 83°, b. p. 233 to 234°. The . a 
=e _6-compound melts between 36 and 38° and seems to transform itself into the a-variety — 
_on- ane Ping Both Somgounds colour bluish black with ferric chloride. If heated — 
<a 2 9 
giveth 
