Ammonium Chloride → Ethyl 7-(2-amino-4-(tert-butoxycarbonyl)phenoxy)-8-bromo-6-chlorochroman-4-carboxylate

Participants

Reaction Steps

To a stirred solution of ethyl 8-bromo-7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6-chlorochroman-4-carboxylate (2.00 g, 3.59 mmol) in tetrahydrofuran (15 mL) at ambient temperature was added zinc dust (4.70 g, 71.8 mmol), followed by saturated ammonium chloride solution (7.5 mL). The resulting mixture was stirred at ambient temperature for 1 hour. The mixture was filtered through a glass microfibre filter to remove the insoluble zinc solids, and the solids were washed twice with tetrahydrofuran. The combined filtrate and washings were concentrated to remove most of the tetrahydrofuran, and the residue was partitioned between ethyl acetate (100 mL) and water (50 mL). The organic layer was washed with brine (50 mL), then dried over sodium sulfate and concentrated to afford ethyl 7-(2-amino-4-(tert-butoxycarbonyl)phenoxy)-8-bromo-6-chlorochroman-4-carboxylate as a light brown glass (1.61 g, 85% yield).

Provenance & Evidence