The interaction of 2-ethoxymethylidene-3-oxo esters and their analogues with 5-aminotetrazole is an efficient synthetic approach to novel azaheterocycles. 2-Ethoxymethylidene-3-oxo esters bearing alkyl substituents react with 5-aminotetrazole to form ethyl 2-azido-4-alkylpyrimidine-5-carboxylates which are capable of subsequent nucleophilic substitution. The use of diethyl 2-ethoxymethylidenemalonate in this reaction resulted in ethyl 7-hydroxytetrazolo[1,5-a]pyrimidine-6-carboxylate, while ethyl 2-ethoxymethylidenecyanoacetate yielded 5-[2,6-diamino-3,5-bis(ethoxycarbonyl)pyridinium-1-yl]tetrazol-1-ide through an alternative pathway. Ethyl 2-benzoyl-3-ethoxyprop-2-enoate reacted with 5-aminotetrazole by two reaction routes to form ethyl 2-benzoyl-3-(1H-tetrazol-5-ylamino)prop-2-enoate and ethyl 7-(1-ethoxy-1,3-dioxo-3-phenylpropan-2-yl)-5-phenyl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate.
2-乙氧甲基亚甲基-3-酮基酯及其类似物与5-氨基四唑的相互作用是一种有效的合成新型氮杂环化合物的方法。带有烷基取代基的2-乙氧甲基亚甲基-3-酮基酯与5-氨基四唑反应,形成乙酰基2-氮杂嘧啶-5-羧酸酯,这些化合物能够进行进一步的亲核取代反应。在此反应中使用二乙酰乙二酯,可以得到乙酰基7-羟基四唑并环[1,5-a]嘧啶-6-羧酸乙酯,而使用乙酸乙酯基2-乙氧甲基亚甲基丙烯酸酯,则通过另一种途径生成5-[2,6-二氨基-3,5-双(乙氧羰基)吡啶-1-基]四唑-1-化物。乙酰基2-苯甲酰基-3-乙氧基丙烯酸酯通过两种反应途径与5-氨基四唑反应,形成乙酰基2-苯甲酰基-3-(1H-四唑-5-基)丙烯酸酯和乙酯基7-(1-乙氧基-1,3-二氧杂环戊烷-3-苯基丙基)-5-苯基-4,7-二氢四唑并环[1,5-a]嘧啶-6-羧酸乙酯。