Acetophenone → 3,3-Diphenylacrolein

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Reaction Steps

First, a Grignard's reagent prepared from methyl chloride and magnesium is reacted with p-amino substituted benzophenone (2), followed by dehydration, to obtain 1,1-diphenylethylene derivative (3). Alternatively, the 1,1-diphenylethylene derivative (3) can be synthesized by reacting a Grignard's reagent, prepared from p-amino substituted bromobenzene, with an acetophenone compound (5), followed by dehydration. Next, a Vilsmeier reagent prepared from phosphorus oxychloride and N,N-dimethylformamide is reacted with the 1,1-diphenylethylene derivative (3) to obtain a 3,3-diphenylacrolein derivative (6). This 3,3-diphenylacrolein derivative (6) which is a mixture of a cis-isomer and a trans-isomer is subjected to a treatment using column chromatography or recrystallization treatment or a combination of these treatments to obtain a 3,3-diphenylacrolein derivative (7) embracing excess trans-isomers. The compound (7) and a diethyl 1,1-diphenylmethyl phosphonate derivative (9) are condensed by a Wittig-Horner reaction to synthesize 1-(p-aminophenyl)-1,4,4-triphenylbutadiene derivative (1) embracing excess tans-isomers (the ratio of trans-isomer≥0.6).

Provenance & Evidence