1-Methyl-1H-imidazole-4,5-dicarboxylic acid19485-38-232 % similar N1-Methylpseudouridine13860-38-332 % similar 2,6-Dichloro-7-methyl-7H-purine2273-93-031 % similar 1-Methylxanthine6136-37-431 % similar Diprophylline479-18-530 % similar