“SCIENTIFIC RESEARCH . me ie 141 
5 
en 
Bikes place, between. the Kectaldehede formed as ahtermiediate pi the ketone added, 
er ‘the hydrogen which in the last stage of the fermentation-process effects the regular — 
hydrogenation down to ethyl alcohol. Hence, just so much of the acetaldehyde escapes 
re duction as corresponds to the ketone reduced. Naturally, it is here the question of 
ar equilibrium, limited by the tendency to pass en within the normal course of alcoholic 
_formentation. 
-Methylheptenone has a decidedly unfavourable action upon the fermentation-process, 
‘more especially the fermentation velocity is retarded considerably. This results in the 
fact that an excess of the ketone is able to lock out, up to a certain degree, the 
intermediate acetaldehyde from normal hydrogenation. Hence, with methylheptenone, 
the hydrogenation passes off at the expense of the fermented sugar. 
In order to identify the methylheptenol, the authors converted it into the isomeric 
, oxide (IX) described by Wallach*) and by Rupe and poe and giving a well-— 
_ defined addition product with hydrogen ferricyanide. 
: For identification of methylheptenone, Neuberg and Lewite recommend to prepare 
a the p-ni eee razone forming light-yellow needles, m. p. 103.5 to 104°. | 
4 CH, ; is 5 
; SO eo CH, CO.CH, NaNH; 
. . (1) Methylethylketone. (II) Ethyl chloroacetate. 
eo CHAO. sep CHa . 
r, ye NEN —CO, ——> 
Be GH” SCH. C0; GH, | CsHe” ~ NCH-CO;H 
Z ii Methylethylglycidic ester. tate a Op 
vt. (IV) Methylethylglycidic acid. 
ere Same . 
5 CHa, OH - z Chie 
q >e — H.0 He =) CH-CHO  * 
—  GHs~ ~ SCHR): CO.H | Cae 
’ (V) Dihydroxy acid. (V1) Aaa 
CH, SC: CH- CH, - CH, - CO: CH; armas CH, Oe: CH- CH,- CH: CH(OH). CHe 
(vit) Methylheptenone. bs (VIII) Methylheptenol. 
(CHs)2 C=CHy-CHs- GH. CH: CH; : 
eee 
(IX) Oxide from Methylheptenol. 
~ Neuberg and Kerb*), when reporting on the reduction of citral to geraniol by 
means of yeast, deal also with the preparation of cyclocitral and some crystallised 
derivatives thereof. 3 
_ On biochemical reduction, citral is reduced in the main to geraniol, a small pro- 
portion is converted into an optically active alcohol, concerning the nature of which 
othing positive could yet be stated. In any case, it is not the question of linalool. 
2 For carrying out the reaction, a regular fermentation process is not necessary, 
1e reduction passing off equally well on digesting citral with yeast alone. 
e-- Tie geraniol was identified by its calcium chloride compound and its acid phthalate, 
the silver salt of which was analysed; m.p. 131 to 132°. 
4) Liebig’s Annalen 275 (1893), 171. — %) Berl. Berichte 38 (1905), 1498. — 3) Biochem. Zeitschr. 92 
(18), 111. 
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