150-13-0

123-72-8

4740-24-3

4-(Butylamino)benzoic acid (compound 3) was synthesized as follows: compound 2 (about 3 mmol) was dissolved in 15 mL of methanol, R-methylpyridine-borane (1.1 eq.) and n-butyraldehyde (1.1 eq.) were added. The reaction mixture was sealed with a vented pin plug and the reaction was stirred at room temperature for 16-24 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. To the residue, 10 mL of 1 M HCl solution was added and stirring was continued for 30 minutes at room temperature. Subsequently, the pH was adjusted to neutral with NaHCO3 solution and the target product was extracted with ethyl acetate (2 x 60 mL). The organic layers were combined, washed once with brine (45 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. Finally, the target product compound 3 was purified by column chromatography (eluent: hexane solution of 30% ethyl acetate) to give the target product compound 3 in white powder form in 88% yield. The structure of the product was confirmed by 1H NMR (500 MHz, CD3OD) and 13C NMR (125 MHz, CD3OD).