137807-33-1Relevant academic research and scientific papers
Process for the preparation of linear 1,3-diketones
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, (2008/06/13)
There is disclosed a process for the preparation of 1,3-diketones of formula I STR1 wherein R1 and R2 are each independently of the other C1 -C20 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1 -C4 alkyl and/or C1 -C4 alkoxy, C7 -C9 phenylalkyl or a radical of formula II wherein A is C1 -C12 alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, C1 -C4 alkyl and/or C1 -C4 alkoxy, or is C1 -C12 alkylene which is substituted by hydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1 -C18 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1 -C4 alkyl, NO2 and/or C1 -C4 alkoxy, or is C7 -C9 phenylalkyl, and R3 is hydrogen, C1 -C20 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1 -C4 alkyl, NO2 and/or C1 -C4 alkoxy, or is C7 -C9 phenylalkyl. The process comprises carrying out a Claisen condensation of a ketone of formula III STR2 and an ester of formula IV STR3 wherein R5 is C1 -C5 alkyl, phenyl or phenyl which is substituted by halogen, C1 -C4 alkyl 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 C1 -C5 alkali metal or C1 -C5 alkaline earth metal, in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
