SYNTHESIS AND REACTIONS OF NEW 4-CHLORO-2-METHYLPYRIMIDINO[4',5' 4,5]THIAZOLO[3,2-A]-BENZIMIDAZOLES/

4-Chloro-2-methylpyrimidino [4',5':4,5]thiazolo[3,2-a]benzimidazole (3 ) was prepared by chlorination of 2 which could also be converted dire ctly to 2-methylpyrimidino [4',5':4,5]- thiazolo[3,2-a] benzimidazol-4 -thiol (4). Nucleophilic substitution of 3 with alcohols, phenols, pri mary amines, secondary amines, sodium azide, and mercaptoacetic acid g ave the corresponding derivatives. The thiol derivative 4 was reacted with alkyl/aralkyl halides, phenacyl bromide derivatives, bromoacetone , chloroanilides, bromomalonic ester, and ethyl bromoacetate to afford compounds of potential pharmacological interest.