SummaryThe 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-(Ethoxymethylidene)-3-oxo carboxylic acid esters reacted with tetrazol-5-amine to give ethyl 4-alkyl-2-azidopyrimidine-5-carboxylates capable of undergoing subsequent nucleophilic substitution of hydrogen on C 6 or azido group. The reaction of ethyl 2-benzoyl-3-ethoxyprop-2-enoate with tetrazol-5-amine was accompanied by partial decomposition to afford a mixture of ethyl 3-oxo-3-phenylpropanoate and ethyl 7-(1-ethoxy-1,3-dioxo-3-phenylpropan-2-yl)-5-phenyl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate. Ethyl 7-hydroxytetrazolo[1,5-a]pyrimidine-6-carboxylate was formed as a result of cyclization of diethyl 2-(ethoxymethylidene)propanedioate with tetrazol-5-amine.We examined the reactions of 2-(ethoxymethylidene)-3-oxo carboxylates 1 a -1 d and diethyl 2-(ethoxymethylidene)propanedioate (1e) with tetrazol-5-amine. Heating of 1a-1c with tetrazol-5-amine in boiling ethanol resulted in the formation of an inseparable mixture of products, whereas the reaction in
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.