| 摘要 |
<p>of formula (I) (where R1 is OH, lower alkoxy or di(lower alkyl) amino; R2 and R3 are H or lower alkoxy; and R4, R5 and R6 are H or alkyl, or R4 + R5 is (CH2)x in which x is 2, 3 or 4, and R5 can also be lower alkoxycarbonyl), e.g. 1,7-bis(p-hydroxyphenyl)-5-hydroxy-1,4,6-heptatriene-3-one, are prepd. by reacting a 1,2-glycol or a hydroxy-acid a beta-diketone of formula R4CH2-CO-CHR5-CO-CH2R6, and boron oxide or aluminium hydroxide in a solvent and/or azeotroping agent under the conditions of an azeotropic distn. to give a spiro cpd.; reacting the spiro cpd. with an aldehyde of formula (III) in the presence of a catalyst with azeotropic removal of water of reaction so as to form a complex which separates out from the reaction mixt.; sepg. off the complex and decomposing this with water or dilute acid to give (I); and recovering (I) in a conventional manner. The solvent or azeotroping agent used must be one in which the initially formed spiro cpd. is soluble but the subsequently formed complex is insoluble. The prods. are useful as food dyes and as pharmaceuticals, e.g. as cholo kinetic anti-inflammatory, spasmolytic and antibacterial agents. One-pot process is suitable for use on a technical scale which gives (I) in high purity and good yield.</p> |
