.alpha.,.beta.-Imidazoledicarboxylic acid 1H-Imidazole-4,5-dicarboxylic acid 4,5-Dicarboxyimidazole 4,5-Imidazoledicarboxylate 570-22-9 Glyoxalinedicarboxylic acid Imidazole-4,5-dicarboxylic acid NSC9236