Central Nervous System Activity of 1-aryl-2(thiomethylene benzimidazol-2-yl)-4-(phenyl/p-chlorophenyl)-imidazoles and 1-aryl-2-sulphono-[benzimidazol-2-yl]-methyl-4-(phenyl/p-chlorophenyl)-imidazoles

1-Aryl-2-mercapto-4-(phenyl/p-chlorophenyl)-imidazoles (Ia-1) were condensed with 2-chloromethyl benzimidazole (II) in presence of sodium hydroxide in ethanol to get 1-aryl-2-thiomethylene benzimidazol-2-yl-4-(phenyl/p-chlorophenyl)-imidazoles (IIIa-1). These compounds (IIIa-1) were subsequently oxidised by hydrogen peroxide to get 1-aryl-2-sulphono-[benzimidazol-2-yl]-methyl-4 and (phenyl/p-chlorophenyl)-imidazoles (Iva-1). All the compounds (IIIa-1) and (Iva-1) exhibited central nervous system depressant action on albino mice. All the compounds are non-toxic and possess some sedative activity.