Reaction of Diazomethane with 2-Acetyl-5,5-diphenyl-2,4-pentadienoic Acid and Related Compounds

概要

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Reaction of 2-acetyl-5,5-diphenyl-2,4-pentadienoic acid (Ia) and its methyl ester (Ib) with diazomethane gave rise to 3-acetyl-3-methoxycarbonyl-4-(β-phenylstyryl)-1-pyrazoline (IIb), which by elimination of nitrogen afforded methyl 2-acetyl-6,6-diphenyl-3,5-hexadienoate (IIIb). Similar reaction of 3-(γ-phenylcinnamylidene)-2,4-pentanedione (Ic) and dimethyl γ-phenylcinnamylidenemalonate (Id) with diazomethane gave the adduct corresponding to 1-pyrazoline derivatives (IIc, IId), respectively. Heating of these compounds afforded denitrogenated products. Similarly, methyl 2-acetyl-5-phenyl-2,4-pentadienoate (Ie) and 3-cinnamylidene-2,4-pentanedione (If) reacted with diazomethane, followed by elimination of nitrogen, to afford methyl 2-acetyl-6-phenyl-3,5-hexadienoate (IIIe) and 3-(4-phenyl-1,3-butadienyl)-2,4-pentadione (IIIf), respectively. The reaction of the pyrazoline (II) to give compound (III) involves the novel ring-cleavage of the cyclopropane intermediate, such as methyl 1-acetyl-2-(β-phenylstyryl)-cyclopropane-1-carboxylate (IX, where R_1=phenyl, R_2=methyl, R_3=methoxy).
社団法人日本薬学会の論文
1976-12-25