Ammonium Chloride → (S)-methyl 2-((tert-butoxycarbonyl)amino)-3-(4-carbamoyl-2,6-dimethylphenyl)propanoate

Participants

Reaction Steps

Into a stirrng solution of the benzoic acid from Step B (3.00 g, 8.54 mmol), PyBOP (6.68 g, 12.8 mmol) and HOBt (1.74 g, 12.8 mmol) in DMF (36 mL) was added DIPEA (5.96 mL, 34.2 mmol) and NH4Cl (0.92 g, 17.1 mmol). The resulting mixture was stirred at rt for 40 min before being partitioned between aqueous NH4Cl solution and EtOAc. The separated organic phase was washed with 2 N citric acid aqueous solution, saturated aqueous NaHCO3 solution and brine, and dried over Na2SO4 overnight. After concentration, the residue was purified by flash column chromatography (eluent: EtOAc) to give the title amide. 3.00 g, 100%; 1H NMR (300 MHz, CDCl3): δ 1.36 (9H, s), 2.39 (6H, s), 3.11 (2H, J=7.2 Hz), 3.65 (3H, s), 4.53-4.56 (1H, m), 5.12 (1H, d, J=8.7 Hz), 5.65 (1H, br s), 6.09 (1H, br s), 7.46 (2H, s); MS(ES+) (relative intensity): 250.9 (100) (M−Boc)+.

Provenance & Evidence