| 摘要 |
A-18049/A/CGM 351 Process for the preparation of linear 1,3-diketones There is disclosed a process for the preparation of 1,3-diketones of formula I (I) wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, C7-C9phenylalkyl or a radical of formula II -A-X-R4 (II) wherein A is C1-C12alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2 C1-C4alkyl and/or C1-C4alkoxy, or is C1-C12alkylene which is substituted by hydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl. The process comprises carrying out a Claisen condensation of a ketone of formula III (III) and an ester of formula IV (IV) or (V) wherein R5 is C1-C5alkyl, phenyl or phenyl which is substituted by halogen, C1-C4alkyl or hydroxy, the reaction being carried out with the base used as catalyst, a hydride of an alkali metal or alkaline earth metal or an alcoholate of a C1-C5alkali metal or C1-C5alkaline earth metal, in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
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