By. 
to 170°, were separated and more closely determined by ascertaining their ‘carb 
eM Sie Ee we) wie 
constituents in the colloidal cinnamate ‘mixture of the various we of lao. 3 
with cinnamic acid chloride, cinnamic anhydride, and cinnamic acid, obtained at 
content and rotatory power. From the anhydride’ melt they succeeded in obtaining 
cinnamic acid preparations with rotatory powers up to [#]—9°, together with a colloidal — 
cinnamate mixture insoluble in ligroin with a rotatory power of nearly 100°. In conta 
with this only 2 to 3° rotating cinnamic acid could be got from the chloride melt, | 
although very highly rotating dicinnimate ([«]) — 275°) was plentifully present. ~ 7 
The authors emphasise that this state of affairs once again refutes the Mee 
that the activity of the cinnamic acid preparations could be caused by the cinnamate 
mixed with them, and prove that as a matter of fact, asymmetric cinnamic acid molecules — 
had been formed in the melts investigated. 
wane 
‘” 
Dehydroisofenchoic Acid.—A work by N.J. Toivonen!) gives an explanation of a a 
series of peculiar reactions in the oxidation of dehydroisofenchoic acid (I). In it the 
active components of the d./-dehydrozsofenchoic acids, which previously had not been 
prepared, are also described. e 
The product obtained after oxidising the unsaturated dehydrozsofenchoic acid withe 
alkaline permanganate solution was itself unsaturated, hence it could not be the first ~ 
oxidation product. This. had changed in course of time, and the alkalinity of idee 
oxidising liquid was the cause of this change. If.one proceeds as ordinarily, by adding 
(CHs)oC ‘ COOH (CHs),C————_CO— COOH CN) is 
| CH | | CH 
CH;--C COOH bus C—O _. ‘CH;——C=0 
las CH (Ill) Dimethyleyclopentenone- 
‘ J q pes ? carboxylic acid. . 
(1) Dehydroisofenchoic acid. (Il) «, 0-Diketo-@, 6-dimethyl- 
caproic acid. 
(CH,)sC ———-C(OH)3—COOH _— (CH;),C —-—-CO—-COOH (Crayc —_ cogn 
CHe COOH CH, COOH CH, COOH 
(IV) a, a-Dihydroxy-8, @-dimethyl- (V) a-Keto-6, 6-dimethyl- (VI) a, one Ms 
glutaric acid. glutaric acid.  -acid. 
the permanganate solution drop by drop to the sodium carbonate solution of the dehydro- " 
isofenchoic acid, till the colour stays; then a well-crystallising unsaturated acid of the 
composition CsH, Os; (II) is obtained. The first oxidation product of dehydroisofenchoic 
acid, the saturated, viscid «,0-diketo-@,6-dimethylcaproic acid CsH,2O0, (Il), can ‘Bey 
obtained if a plentiful supply of CO. is passed into the solution durite ae 
or by mixing it with a sufficient amount of aluminium sulphate, and’ slightly acidifying © 
immediately after oxidation. By the action of alkalies the acid CsHi.O, changes into 
the already mentioned dimethylcyclopentenone-carboxylic acid CgHioO3 (ill).. This on 
further oxidation with alkaline permanganate yields the eadihydroxy-p, 6-dimetByl 
glutaric acid C,Hi,0, (IV) and the a, a-dimethylsuccinic acid C,H 0. (VI). i on 
1) Liebig’s Annalen 419 (1919), 176. 
