New heterocyclic structures. [1,3]Thiazino[3,2‐<i>a</i>]purine and [1,2,3]triazolo[4,5‐<i>d</i>][1,3]thiazino[3,2‐<i>a</i>]pyrimidine

Abstract

Abstract Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2‐ a ]purine and [1,2,3]triazolo[4,5‐ d ]‐[1,3]thiazino[3,2‐ a ]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4‐dihydro‐7,8‐diamino‐2 H ,6 H ‐pyrimido[2,1‐ b ][1,3]thiazin‐6‐one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6‐diamino‐2,3‐dihydro‐2‐thioxo‐4(l H )‐pyrimidi‐none with 1,3‐ or 1,2‐dibromoalkane, respectively.