Synthesis of xanthines by cyclization of the Michael-type adducts from 6-aminouracils and diethyl azodiformate

Abstract

Treatment of the Michael-type adducts from 6-alkylamino-1,3-dimethyluracils and diethyl azodiformate (DAD) with oxidizing agents such as nitrobenzene, lead tetra-acetate, and lead dioxide as well as DAD itself caused dehydrogenation, followed by thermal cyclization, to give the corresponding theophyllines. Treatment of 6-alkyl-aminouracils with an excess of DAD gave directly the corresponding xanthine derivatives. Reactions of 6-amino-5-(1,2-bisethoxycarbonylhydrazino)-1,3-dimethyluracil with aromatic aldehydes and with dimethylformamide diethyl acetal gave the corresponding 8-aryltheophyllines and 8-dimethylaminotheophylline, respectively.