ae 7 
= z 
. | _ NOTES ON SCIENTIFIC RESEARCH. 139 
or with sodium hypobromite, gives rise to a monobasic saturated acid CsHi2O:, m. p. 
38 to 39°. The same acid is formed when dibromo-dsosantenone is oxidised. 
Menthone. On p. 142 of our last April Report we referred to methyl-3-menthanol-3, 
a body which has been prepared by J. Wanin. A. Arbusov’) now states this alcohol 
has already previously been decribed in detail by Zelinski and himself. 
o-Menthone. A. K6tz?) describes an o-menthone-3 (methyl-1-sopropyl-2-cyclo- 
hexanone-3). He reduced by Paal’s method methyl-1-isopropyl-2-cyclohexene-1-one-3, 
from which he obtained o-menthone-3, a liquid with a faint odour of peppermint; 
b. p. 204° (95 to 96° at 15mm.). The semicarbazone melts at 204 to 205°; no oxime 
could be obtained’). 
Dibromomenthanone. According to G.Cusmano%), the 1,9-dibromomenthanone-3 
(dibromomenthone) described by Beckmann and Eickelberg is in reality a 2,4-dibromo- 
menthanone-3 (I). That one bromine atom is in 4-position is evident from the fact 
that 2,4-dibromomenthanone-3 may also be obtained by brominating 4-monobromo- 
menthone. On the other hand, the positton of the second. bromine atom in 2 is 
proved by the conversion of dibromomenthone into buchu-camphor (diosphenol). When 
the dibromomenthone is shaken with 2,5p.c. potash liquor until it is dissolved, and 
the liquid is then saturated with carbon dioxide, the result is buchu-camphor (m.p. 
84°; semicarbazone, m.p.219 to 220°). The only explanation of the reaction is that 
the bromine in 4-position is eliminated in the form of hydrobromic acid, whereas the 
bromine in 2-position is replaced by hydroxyl, giving rise to an unsaturated keto 
alcohol (II). This alcohol is then converted into a diketone (III) which, according to 
Semmler and Mac Kenzie, is readily converted into buchu camphor (IV). The action 
of bromine upon buchu camphor in chloroform solution gives rise to monobromo 
buchu camphor (m.p. 85°), which, when treated with a 2p.c. aqueous potash liquor 
is converted into hydroxy thymoquinone. 
; When amines are allowed to react with dibromomenthone, one bromine atom is 
replaced by an imino-residue. Thus, with aniline the anilide, m.p.195°, results. 
8-Aydroxyl amide melts between 158 and 160°. 
With nitrous acid dibromomenthone yields an isonitramine Cy oHigOBr-N2O2H, 
which is decomposed with great violence at 35° with evolution of red vapours. 
Za 
HC CO He. co H.C. CO HC. /C0 
CBr C CH CH 
C; H, Cs H, Cs H, Cs H, 
(I) 2,4-Dibromo- (Il) Unsaturated ketoalcohol. (Ill) Diketone. (IV) Buchucamphor. 
menthanone-3. 
Camphor. |. Bellucci and L.Grassi*) have closely investigated the camphor- 
Sulphur dioxide system, with the object of determining the part which is played by 
*) Journ. russ. phys. chem. Ges. 45 (1913), 700; Chem. Zentralbl. 1918, II. 1482. — *) Liebigs Annalen 400 
(1913), 85. — *) Comp. Report April 1911, 182; April 1918, 143. — +4) Atti R. Accad. dei Lincei (5) 22, II (1913), 
569; Chem. Zentralbl. 1914, 1.976. — 5) Atti R. Accad. dei Lincei (5) 22, Il (1913), 676; Chem. Zentralbl. 1914, 1 978. 
