A series of 2-(4-substituted-1-(homo)piperazinyl)benzimidazoles was prepared and tested for H1-antihistaminic activity in vitro and in vivo. Most of the compounds showed antihistaminic activity and some of the 1-[2-(substituted-oxy)ethyl] derivatives exhibited potent activity. In a structure-activity comparison it was found that the oxygen atom in the 2-(substituted-oxy)ethyl group at the 1-position
Syntheses were conducted of novel benzimidazole derivatives that suppress histamine release from mast cells, inhibit 5-lipoxygenase, and possess antioxidative action. Among the compounds synthesized, 1-[2-[2-(4-hydroxy- 2,3,5-trimethylphenoxy)ethoxy]ethyl]-2-(4-methyl-1- homopiperazino)benzimidazole (22) potently suppressed histamine release from rat peritoneal mast cells triggered by the antigen-antibody