SYNTHESIS AND REACTIONS OF SOME NEW BENZIMIDAZOLES .2.

Interaction of (p-benzimidazol-2-ylphenoxy)acetic acid hydrazide (1) w ith isothiocyanates affords acetylthiosemicarbazides (2a-c) which on c yclisation give 3a-c. Reaction of 3a with alkyl halide, ethyl chloroac etate and/or diethyl bromomalonate affords S-alkyl derivatives (4a-e). Condensation of 3a with p-substituted-phenacyl bromides gives 5a-c. T reatment of 3a with N-aryl and N-heterocyclic-2-chloroacetamides gives 6a-c. Reaction of 3a with CH2O in the presence of morpholine or p-tol uidine affords the Mannich bases (7a,b). Cyclodehydration of 2a-c with phosphoric acid gives the thiadiazoles (8a-c). Interaction of 1 with CS2 gives 9 which is reacted with hydrazine hydrate to give 10. Conden sation of 10 with aromatic aldehydes gives the azines (11a-f). Reactio n of 10 with p-substituted-phenacyl bromide gives the uncyclised produ cts 12a-c rather than cyclised ones 13a-c. Several compounds are scree ned for antibacterial activities.