Syntheses of the metabolites of 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H benzimidazole difumarate (KG-2413) and related compounds

The metabolites of 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H-b enzimidazole difumarate (KG-2413), which has a potent H1-antihistaminic activity, were predicted on the basis of metabolic studies of related compounds and were synthesized to aid in identification of the actual metabolites and for examination of their antihistaminic activity. Among the twelve compounds prepared, nine compounds were actually found as the metabolites of KG-2413 in rat urine. The antihistaminic activities of these metabolites were found to be lower than that of KG-2413.