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 R1=phenyl, R2=methyl, R3=methoxy).
2-乙酰基-5,5
-二苯基-2,4-五烯酸 (Ia) 及其甲基酯 (Ib) 与
重氮甲烷反应生成 3-乙酰基-3-甲氧基羧基-4-(β-
苯乙烯基)-1-
吡唑啉 (IIb),通过氮的消除得到甲基 2-乙酰基-6,6
-二苯基-3,5-六烯酸酯 (IIIb)。类似地,3-(γ-苯基
肉桂醛)-
2,4-戊二酮 (Ic) 和二甲基 γ-苯基
肉桂醛马来酸酯 (Id) 与
重氮甲烷反应分别生成与 1-
吡唑啉衍
生物相对应的加成物 (IIc, IId)。加热这些化合物可得到去氮化产物。同样,甲基 2-乙酰基-5-苯基-2,4-五烯酸酯 (Ie) 和 3-
肉桂醛-
2,4-戊二酮 (If) 与
重氮甲烷反应,随后消除氮,生成甲基 2-乙酰基-6-苯基-3,5-六烯酸酯 (IIIe) 和 3-(4-苯基-
1,3-丁二烯基)-
2,4-戊二酮 (IIIf)。
吡唑啉 (II) 的反应形成化合物 (III) 涉及
环丙烷中间体的新颖环裂解,如甲基 1-乙酰基-2-(β-
苯乙烯基)-
环丙烷-1-
羧酸酯 (IX,其中 R1=苯基,R2=甲基,R3=甲氧基)。