Trimethyl orthoacetate → Benzoxazole, 6-bromo-4-fluoro-2-methyl-

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-amino-5-bromo-3-fluorophenol (1 equiv), ytterbium(iii) trifluoromethanesulfonate (0.01 equiv), and trimethyl orthoacetate (1.2 equiv) in EtOH (1.3 M) was heated to 90° C. for 2 h. The reaction mixture was filtered through celite and washed with EtOH. The residual filtrate was concentrated in vacuo, then saturated aqueous sodium bicarbonate added and extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified using silica gel chromatography (0 to 60% ethyl acetate in hexane) to afford the title compound (73% yield). MS (ESI) m/z 232.2 [M+H]+.

Provenance & Evidence