Though condensation at either the carbonyl oxygen or the unsaturaced carbon adjacent to nitrogen of enaminones can occur in the reaction with the active methylene of ethyl acetoacetate, the results obtained in the condensation reactions of the enaminones 1 and 2 with ethyl acetoacetate in the presence of Knoevenagel catalysts to give the α-pyranones 3 and 4 and with the dianion of ethyl acetoacetate to give the ethyl salicylates 6 and 19 show that these reactions proceed at the latter position.
尽管在与
乙酰乙酸乙酯的活性
甲烷中,与enaminones的反应中,碳酰氧或相邻于氮的非饱和碳处都可能发生缩合,但enaminones 1和2与
乙酰乙酸乙酯在Knoevenagel催化剂存在下进行的缩合反应,生成
α-吡喃酮3和4,以及与
乙酰乙酸乙酯的二阴离子反应生成
乙酸水杨酯6和19的结果表明,这些反应在后者位置进行。