反应详情

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.

1. temperatureat reflux temperature for 2 h
2. concentrationconcentrated
3. additionTrifluoromethane-sulfonic acid (60 ml) is added to the residue
4. stirringthe resulting mixture is stirred at 55° C. for 4 h
5. additionthe mixture is poured into ice-cold water
6. stirringthe resulting mixture is stirred for 5 min
7. customThe precipitate formed
8. customis separated by filtration
9. washwashed with water
10. dissolutiondissolved in ethyl acetate
11. washThe solution is washed with aqueous NaHCO3 solution
12. dry with materialdried (Na2SO4)
13. concentrationconcentrated
14. customThe residue is chromatographed on silica gel (cyclohexane/ethyl acetate 90:10→80:20)