4-Anilino-3-nitrobenzoic acid → 3-Amino-4-phenylamino-benzoic acid

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Reaction Steps

A 3-neck flask was charged with 3-nitro-4-phenylaminobenzoic acid (see Synthesis Example 1-1) (1.67 g, 6.70 mmol), palladium/carbon (Pd:10%, 0.170 g), and tetrahydrofuran (34 mL), the atmosphere was replaced with hydrogen using three cycles of vacuum/hydrogen purge, and this was stirred at room temperature for 2.5 hours. After substituting in nitrogen, distilled water (20 mL) was added and this was stirred for 10 minutes, insoluble material was filtered off through a Celite layer (20 mm thickness), and this same layer was further washed with tetrahydrofuran (20 mL, 3 times). The filtrate and the wash solutions were combined, and the solvent was distilled off under reduced pressure. This was successively extracted with ethyl acetate (approx. 50 mL, 4 times), washed with distilled water (30 mL), and dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and further drying under reduced pressure yielded the title compound (1.45 g, 95.3% yield) as a pale yellow solid.

Provenance & Evidence