Dimethylformamide → 1H-Inden-1-one, 4-bromo-2,3-dihydro-5-(trifluoromethyl)-

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Reaction Steps

Oxalyl chloride (6.8 mL) and N,N-dimethylformamide (0.1 mL) are added to a solution of 3-(2-bromo-3-trifluoromethyl-phenyl)-propionic acid (15.7 g) in dichloromethane (150 mL) at room temperature. The solution is stirred at reflux temperature for 2 h and then concentrated. Trifluoromethane-sulfonic acid (60 ml) is added to the residue, and the resulting mixture is stirred at 55° C. for 4 h. After cooling to room temperature, the mixture is poured into ice-cold water, and the resulting mixture is stirred for 5 min. The precipitate formed is separated by filtration, washed with water, and dissolved in ethyl acetate. The solution is washed with aqueous NaHCO3 solution, dried (Na2SO4), and concentrated. The residue is chromatographed on silica gel (cyclohexane/ethyl acetate 90:10→80:20) to afford the title compound. LC (method 4): tR=1.04 min.

Provenance & Evidence