| 摘要 |
<p>A process for the preparation of a benzylidene compound of the formula <IMAGE> in which R1 is hydrogen or one or two substituents independently selected from the group consisting of nitro, cyano, halogen, SO3H, alkyl, alkoxy and fluorinated alkyl, each with 1 to 4 C atoms and two or three fluorine substituents, and R3 is alkyl with 1 to 10 C atoms, which is optionally interrupted by an oxygen in the chain or is optionally substituted by fluorine, chlorine, hydroxyl or a methylbenzylamine group, comprising reacting an acetal of the formula <IMAGE> in which R2 each independently is alkyl with 1 to 6 C atoms, which is optionally substituted by phenyl, or the two radicals R2 conjointly form an alkylene radical with 1-6 C atoms, with a beta -ketocarboxylic acid ester of the formula CH3CO-CH2-COOR3 in the presence of an acid at a temperature between about 40 DEG and 120 DEG .</p> |
