Synthesis of Spiroheterocyclic Systems from Barbituric Acids and N,N-Disubstituted o-Aminobenzaldehydes
作者:K. A. Krasnov、V. G. Kartsev
DOI:10.1007/s11178-005-0263-2
日期:2005.6
Reactions of barbituric, 1,3-dimethylbarbituric, and 2-thiobarbituric acids with 2-(1-pyrrolidinyl)benzaldehyde, its 6- and 7-membered homologs, and 4-phenylpiperazine and morpholine analogs lead to formation of fused systems with a spirocyclic 2,4,6-trioxopyrimidine fragment. The process involves intermediate formation of labile 5-arylmethylidenebarbituric acids which exhibit t-amino effect and undergo spontaneous isomerization to give the final products. The observed spirocyclizations are characterized by an anomalously high rate.
巴比妥酸、1,3-二甲基巴比妥酸和2-硫巴比妥酸与2-(1-吡咯烷基)苯甲醛及其6-和7-成员同系物,以及4-苯基哌嗪和吗啉类似物的反应,形成了具有螺环结构的2,4,6-三氧嘧啶片段的融合体系。该过程涉及不稳定的5-芳基甲烯基巴比妥酸的中间体形成,这些中间体表现出t-氨基效应,并自发异构化,生成最终产物。观察到的螺环化反应特征是反应速率异常高。