Pyridine → Methyl 2-(1-(benzyloxycarbonyl)-2-methylpyrrolidin-2-yl)benzo[d]oxazole-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of benzyl 2-(2-hydroxy-3-(methoxycarbonyl)phenylcarbamoyl)-2-methylpyrrolidine-1-carboxylate (550 mg, 1.33 mmol) in anhydrous toluene (10 mL) was added anhydrous pyridine (0.583 mL, 7.3 mmol), then thionyl chloride (0.39 mL, 7.3 mmol) was added, the mixture was heated to 110° C. for 6 h. The mixture was cooled to room temperature and poured into ice water (100 mL) carefully with vigorous stirring, then extracted with ethyl acetate (50 mL×3). The organic phase was washed with saturated sodium bicarbonate solution and brine, dried over anhydrous sodium sulfate, and concentrated to give crude product. The crude product was purified by chromatography (silica gel, petroleum ether/ethyl acetate=30:1 to 8:1) to give methyl 2-(1-(benzyloxycarbonyl)-2-methylpyrrolidin-2-yl)benzo[d]oxazole-7-carboxylate (164 mg, yield 32%). 1H-NMR (400 MHz, CDCl3): δ 1.63 (s, 3H) 2.02-2.05 (m, 2H), 2.14-2.16 (m, 1H), 2.40-2.44 (m, 1H), 3.73-3.77 (m, 1H), 3.87-3.90 (m, 1H), 3.94 (s, 3H), 4.71-4.73 (d, J=9.6 Hz, 1H), 5.06-5.09 (m, 2H), 6.79-6.81 (d, J=6 Hz, 1H), 6.89-6.92 (m, 1H), 7.02-7.04 (m, 1H), 7.33-7.37 (m, 3H), 7.80-7.95 (m, 2H); LC-MS (ESI) m/z: 395 (M+1)+.

Provenance & Evidence