Synthesis of new sulfonamide derivatives of thiazolo[3,2-a]quinazolin-5-one

A general procedure has been proposed for the synthesis of thiazolo[3,2-a]quinazolin-5-one derivatives containing a sulfonamide group on C⁷ via intramolecular nucleophilic substitution of halogen in 2-halo-5-sulfamoyl-N-(1,3-thiazol-2-yl)benzamides. The effects of the degree of activation of the initial compound and halogen nature on the yield of the target products have been analyzed.