Yield:1221444-24-1 97%

Reaction Conditions:

Stage #1: 2'-methoxy-4'-(trifluoromethoxy)acetophenonewith boron trichloride in dichloromethane at -25 - -18;
Stage #2: with water in dichloromethane;Cooling with ice;

Steps:

92.92A

A solution of l-(2-methoxy-4-(trifluoromethoxy)phenyl)ethanone (17.8 g, 76.0 mmol) in CH₂Cl₂ (178 mL) was cooled to -25 ⁰C and boron trichloride (91.0 mL of a 1.0 M soluton in CH₂Cl₂, 91 mmol) was added dropwise keeping the internal temperature <-18 ⁰C. Following addition, analysis by LCMS indicated complete reaction. The reaction mixture was poured into ice (75 g) and partitioned. The organic layer was washed with with water(50 mL), dried (Na₂SO₄), filtered, and concentrated to give 16.2 g (73.6 mmol, 97 % yield) of the title compound. MS (DCI/NH₃) m/z 238 (M+NH₄)⁺.

References:

WO2010/45401,2010,A1 Location in patent:Page/Page column 99