1,2-Benzenedicarboxylic acid, 4,5-dimethoxy- 4,5-Dimethoxy-1,2-benzenedicarboxylic acid 4,5-Dimethoxyphthalic acid 577-68-4 NSC155484 Phthalic acid, 4,5-dimethoxy- m-Hemipic acid m-Hemipinic acid