Synthesis and crystal structure of a covalently hydrated 8‐thia‐1,4‐diazacycl[3.3.2]azine

Abstract

Abstract Condensation of ethyl 4‐chloroacetoacetate with 4‐amino‐6‐hydroxy‐2‐pyrimidinethiol produced ethyl 3‐hydroxy‐5‐amino‐7‐oxothiazolino[3,2‐ a ]pyrimidin‐3‐acetate ( 7a ) on crystallization. Subsequent ring closure of 7a produced the tricyclic 6a‐hydroxy‐5,6,6a,7‐tetrahydro‐8‐thia‐1,4‐diazacycl[3.3.2]azin‐2,5‐dione ( 8 ). The structure of 8 was confirmed by crystal x‐ray diffraction analysis.