[N+:1]([C:4]1[CH:5]=[C:6]([CH:10]=[C:11]([N+:14]([O-])=O)[C:12]=1[OH:13])[C:7]([OH:9])=[O:8])([O-])=O>C(O)(=O)C.[Pd]>[NH2:1][C:4]1[CH:5]=[C:6]([CH:10]=[C:11]([NH2:14])[C:12]=1[OH:13])[C:7]([OH:9])=[O:8]3,5-Dinitro-4-hydroxybenzoic acid (Aldrich) (4.56 g, 20 mmole) was dissolved in glacial acetic acid (25ml) and 10% Pd/C (15 mg) was added. The mixture was hydrogenated under hydrogen gas at 60 psi at 60° C. for 4 hours. It was then filtered through a celit pad and evaporated to dryness. The residue was crystallized from water to give 3,5-diamino-4-hydroxybenzoic acid (2.35g, 70%), m.p. 205° C. (lit ref., Simandi et al., Hungarian Patent 53602-A2-901128 (1990), m.p. 205° C.).
Wird geladen…