= ; Ae COoTt 
Pee = ECOL. | ~ CH-CO.H 
“SS et Camphenic acid. 
ee. ca $ 
xe Panic acid. We pointed ‘out on page 81 of our ‘April Beran 1915 that, Accordita: 
to E. Erlenmeyer, it was possible to obtain cinnamic acid and benzaldehyde in an 
optically active state by so-called asymmetric induction. E. Wedekind*) questioned at 
2 the: time eueye's s indications reparding the optically active benzaldehyde « and tri 
= 
a 
= 
= 
L 
i 
-cinnamic acids. He feos at first the contiguous objection that the activi 
_cinnamic acid, as established before, might have been foreshadowed by the admixt 
. of other optically active bodies. These, however, would have to be of an enorm 
rm rotatory power, unattained by far up to now, to be able to afford the high rotat 
Shee observed, without sensibly interfering with the uniformity of the cinnamic aci 
__ It was further investigated up to what limit the admixtures of tartaric acid and cinnamate ~ 
S in the preparation could be ascertained, the analytical carbon value being found to — 
Fi be the most sensitive indicator. From preparations, in which a content of from 2. toss 
me 10 per cent. of cinnamate was to be presumed according to this method, it was p 
= sible to remove it through recrystallization from ligroin. The cinnamic acid thus — 
tose remained ‘strongly active. In preparations, showing a difference of only 0 
to 0.06 per cent. in the carbon content, the main part of the rotation must in any case 
a be a to the active cinnamic acid, and to it alone if the differences are still smaller. 
Same a * cs ; 
ih Riesesties particulars about the properties of allyl and methyl cinnamates, poly- 
eetred in direct sunlight, have been published by C. Liebermann, G. Mihle and — 
M. ‘Kardos?). The former can conveniently be purified by shaking it with methyl 
alcohol, which must be continued until a sample of the alcohol used for washin eet 
_ evaporates without leaving any residue. The purified ester forms a white, loose 
_ powder, which readily dissolves in chloroform. Cold benzene makes it gelatinize, 
enc a good solution is obtained on heating. It was impossible to saponify the ester 
is ‘through boiling it for a considerable time with a 20 per cent. alcoholic potash lye. 
ay After having been dried at 110°, about 25 per cent. of the ester had become connie 
| oluble in chloroform. If the temperature is raised, this change takes place to a 
= rer extent. The optimum of the converting temperature lies between 138 and 140°. 
. _ The methyl cinnamate. polymerized by light dissolves well in chloroform. Light = 
a petroleum ‘precipitates it from concentrated solutions as a fine, white powder, melting 2 
a little « above 300°. On being heated up to 140° for some time, methyl polycinnamaties ms 
: ; 
ay Berl. Bertone 47 (1914), 3172. — *) Biochem. Zeitschr. 74 (1916), 137; Chem. Zentralbl. 1916, II. 57 
4 : A . . 
2 Sot at Berichte 43 (1915), 1645. oe: C. Liebermann and M. Zsuffa, ibtdem 44 (1911), 845; C, Liebermat nn o 
