Efficient Synthesis of Pyrimido[1,2-c] [1,3]benzothiazin-6-imines and Related Tricyclic Heterocycles by SNAr-Type C-S, C-N, or C-O Bond Formation with Heterocumulenes

摘要

A simple and practical synthetic method of pyrimido[1,2-c]- [1,3]benzothiazin-6-imines and related tricyclic heterocycles has been developed. Treatment of 2-(2-haloaryl)- tetrahydropyrimidines with NaH and a heterocumulene such as carbon disulfide, isothiocyanates, and isocyanates in DMF provides the desired cyclization products through a regioselective SNAr-type reaction. This method provides direct access to PD 404182 and related compounds.