Potassium Carbonate → Ethyl 7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6,8-dichlorochroman-4-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of ethyl 6,8-dichloro-7-hydroxychroman-4-carboxylate (35 g, 120.22 mmol), tert-butyl 4-fluoro-3-nitrobenzoate (31.1 g, 128.93 mmol), K2CO3 (24.923 g, 180.33 mmol), and 1-methyl-2-pyrrolidinone (500 mL) was purged with Argon (bubbled through) for 15 minutes. The mixture was heated to 80° C. for 4 hours under Argon atmosphere. The mixture was cooled to ambient temperature and poured into 3 liters of water. The pH was adjusted to pH 2 by addition of concentrated HCl (4×10 ml). A solid precipitated out as HCl was added and gas evolution was observed. The crude mixture was filtered and the solid was dissolved in EtOAc (1 liter). The EtOAc solution was washed with 2N HCl solution (200 ml), water (2×200 ml), and brine (200 ml), dried over MgSO4, filtered, and concentrated to provide 64.1 g of the title compound as a dark solid (104%).

Provenance & Evidence