lOI 
i-cvclohexanone-3, by means of potassium cthylale and isopropyl iodide, 
he arrived at 4 -acetyl menthone, 
CH..CH<'^"^-CO>c<<=°-<^"' 
CH,_CH, CH.(CH3), 
an oil of the boiling point 133 — 135^ (13 mm), specific gravity 0,967 
(15° C), nj) = 1,45737. By eliminating the acetyl group with alcoholic 
potash solution, a ketone with a menthone - like odour resulted; boiling 
point 207 to 208° at atmospheric pressure. The menthone semicarbazone 
produced from it melted at 179 to 180° (according to Wallach at 
184°), the menthoximic acid, obtained by v. Baeyer and Manas se's 
method, at 98 to 99° (according to v. Baeyer and Oehler^) at 103"^); 
both compounds also gave corresponding analytical figures. As methyl 
cyclohexanone, and the acetyl compound obtainable from it by con- 
densation with acetic ester, can be produced synthetically, it follows 
that the complete synthesis of menthone is an accomplished fact. 
Methyl heptenone. When methyl heptenone is oxidised by 
means of permanganate, it is decomposed into acetone and laevulinic 
acid. The conclusion which Tieman and Semmler have drawn from 
this behaviour, namely that methyl heptenone must therefore contain 
the double linkage in ^-^-position towards the carbonyl group, is not 
entirely free from objection, inasmuch as it had not hitherto been 
possible to isolate the glycol which should be formed in the first place on 
oxidation of this ketone. C. Harries'^) has now however succeeded 
in producing this body, and that in two ways. If methyl heptenone is 
treated with potassium permanganate in a solution of acetone, that is to 
say under conditions, under which the potassium hydroxide formed is not 
expected to effect a change, only about 20 per cent of the ketone were 
invariably attacked, and the corresponding glycol is not formed, but a 
further oxidation into a hydroxyketone Cg Hj4 O.^ takes place immediately. 
But if an aqueous solution of permanganate is employed, methyl hepten- 
one is readily converted into a very well crystallising glycol CgH^gOo 
of the melting point 66 — 67°. As this glycol, on further oxidation 
with permanganate or chromic and glacial acetic acids, yields the same 
hydroxyketone C^H^^Og already mentioned, the latter may also be 
considered a primary oxidation-product of methyl heptenone. The 
hydroxyketone is converted readily into a pyrrol derivative by heating 
with ammonia and acetic acid, and is thereby identified as a ^-diketone. 
When boiled with dilute sulphuric acid, the glycol is converted, with 
Berliner Berichte 29 (1896), 27. 
^) Berliner Berichte 35 (1902), 179. 
