These compounds (I) are usually obtained by acylating 2-o-aminophenylbenzimidazole (II) with carbonyl chlorides, followed by cyclization of the resulting benzimidazole amides (III). We have previously shown [2] that (I) can be obtained in high yields by the direct reaction of (II) with benzoyl chlorides or benzoic anhydrides mixed with acetic acid and acetic anhydride: