Azidotrimethylsilane → ethyl 2-(5-azido-7-bromo-3-chloro-5H-chromeno[2,3-c]pyridin-5-yl)acetate

Participants

Reaction Steps

To a solution of ethyl 2-(7-bromo-3-chloro-5-hydroxy-5H-chromeno[2,3-c]pyridin-5-yl)acetate (38.5 g, 97 mmol) in toluene (400 ml) was added azidotrimethylsilane (38.4 ml, 290 mmol) followed by (diethyloxonio)trifluoroborate (24.48 ml, 193 mmol) under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 16 hours. The reaction mixture was quenched with MeOH (200 mL) and diluted with EtOAc. The organic phase was separated, washed with saturated aqueous sodium bicarbonate solution and brine. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to afford ethyl 2-(5-azido-7-bromo-3-chloro-5H-chromeno[2,3-c]pyridin-5-yl)acetate (40.82 g) which was used in the next step without further purification.

Provenance & Evidence