反应详情

To stirred triethyl orthoacetate (35.0 mL, 190 mmol) was added methyl 3-amino-4,5-dihydroxybenzoate hydrochloride (6.00 g, 27.3 mmol). The stirred suspension was refluxed for 20 min and cooled to room temperature. The reaction mixture was poured into hexane (200 mL). The formed precipitate was separated by filtration and vacuum-dried to afford the desired benzoxazole (4.98 g, 24.04 mmol, 88% yield). 1H NMR (400 MHz, DMSO-d6): δ 10.74 (br. s, 1H), 7.66 (d, J=1.4 Hz, 1H), 7.43 (d, J=1.4 Hz, 1H), 3.85 (s, 3H), 2.62 (s, 3H).

1. temperatureThe stirred suspension was refluxed for 20 min
2. customThe formed precipitate was separated by filtration
3. customvacuum-dried