| 摘要 |
<p>Cyano compounds of the vitamin A series or compounds having vitamin A activity obtained therefrom by conversion are obtained by subjecting an imine of the Vitamin A series to condensation with cyanoacetic acid or with an ester or an amide of said acid. The imine may have the general formula <FORM:0975361/C1/1> in which n is 0 or 1 and R is hydrogen, or an alkyl, phenyl or aralkyl group. The imine may be reacted with the cyanoacetic acid in an ether or an aliphatic, alicyclic, aliphatic-dicyclic or aromatic hydrocarbon at a temperature between -20 DEG C. and 60 DEG C. The resulting nitrile carboxylic acid may be heated by itself or in a solution in toluene, pyridine, collidine, triethyl amine or dimethyl aniline in the presence of a cupric salt to obtain the nitrile in a particularly pure form. In examples, b -ionylidene acetonitrile, a -cyano vitamin A acid, citrylidene-cyanoacetic acid, 4-b -ionylidene -2- nitrile-prop -2- ene carboxylic acid and retinylidene cyano acetic acid are prepared.</p> |
