2-Dimethylaminopyridine → 2',3'-Difluoro-4'-(4-pentyloxybutoxy)-biphenyl-4-carboxylic acid 4-[(R)-1-trifluoromethylheptyloxycarbonyl]-phenyl ester

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Reaction Steps

To a solution of 4′-(4-butoxybutoxy)-2′,3′-difluorobiphenyl-4-carboxylic acid (27) (1 equi.), (4-hydroxybenzoic acid (R)-1-trifluoromethyl-heptyl ester (13, Scheme 7) (1 equi.), and DMAP (dimethylaminopyridine) (0.1 equi.) in THF (25 mL/mmole), DIC (diisopropyl carbodiimide) (1.2 equi.) was added at room temperature. The reaction mixture was stirred at that temperature for 24 h, quenched with water, extracted with ethyl acetate:hexane(1:1), washed with brine, dried over MgSO4, and concentrated in vacuo. Purification by chromatography on silica gel (5% EtOAc/hexanes) gave 2′,3′-difluoro-4′-(4-pentyloxybutoxy)-biphenyl-4-carboxylic acid 4-[(R)-1-trifluoromethylheptyloxycarbonyl]-phenyl ester (28) as a white solid (65%).

Provenance & Evidence