反应详情

A mixture of 5-bromo-thiophene-2-carboxylic acid (5) (207 mg, 1 mmol), oxalyl chloride (420 μl) and catalytic amount of DMF in 5 ml DCM was stirred at r.t for 2 h before evaporation to dryness. The resulting solid residue was dissolved in 5 ml DCM and to which were added 2-fluoroaniline (193 μl, 2 eq) and DIEA (522 μl). The reaction mixture was stirred at r.t for overnight before worked up with EA/aq. HO/brine. The org. phase was concentrated and then purified on a flash silica gel column to give 267 mg (5-bromo(2-thienyl))-N-(2-fluorophenyl)carboxamide (9) as off-white solid. (yield: 89%, purity>95%).

1. stirringThe reaction mixture was stirred at r.t for overnight
2. concentrationphase was concentrated
3. custompurified on a flash silica gel column