137027-51-1 2,6-Diamino-3,4-dimethyl-7-oxopyrano(4,3-g)benzimidazole 2,6-Diamino-3,4-dimethylpyrano(3,4-e)benzimidazol-7(3H)-one Pyrano(3,4-e)benzimidazol-7(3H)-one, 2,6-diamino-3,4-dimethyl-