Investigations on lactams

3-Ethoxy-3,4-dehydrothiazane has been synthesized by the reaction of 3-thiazanone with triethyloxonium fluoroborate. The condensation of 3-ethoxy-3,4-dehydrothiazane with-amino--cyanoacetamide has given 3-amino-2-carbamoylimidazo [2,1-c]thiazane, which is the key compound for the synthesis of a new series of heterocyclic compounds, 4-substituted thiazano[4,3-e]purines.Investigation carried out in the chemical laboratory of Cambridge University, England.