Synthesis and Reaction of Biheterocyclic Thiazolo[3,2-a]pyrimidinium-betaines

摘要

Various new kinds of biheterocyclic bctaines were prepared by the reaction of 3-substituted-6,7-dihydro-5H-thiazolo[3,2-a]pyrimi dine with electrophiles such as isothiocyanates, isocyanates in aprotic solvents, respectively. The biheterocyclic betaines containing methyl group at 3-position of thiazole ring were obtained particularly in good yields at room temperature. These betaines were also reacted with alkyl halide to give quarternary ammonium salts. It was found that these betaines are dissociated in polar organic solvents depending on temperature. And new biheterocyclic compounds via ring transformation were prepared by the reaction of 8-phenyl (thiocarbamoyl)-3-phenyl-6,7-dihydro-5H-thiazolo[3 ,2-a]pyrimidinium-betaine with メ-halo kester メ -halo ester and ャ-halo keto ester.