Boron trifluoride etherate → Avagacestat

Participants

Reaction Conditions

Reaction Steps

To a solution of (R)-2-(4-chloro-N-(4-cyano-2-fluorobenzyl)phenylsulfonamido)-5,5,5-trifluoropentanamide (6.5 g, 13.6 mmol) in EtOH (70 mL) was added NH2OH (50% in H2O, 2.6 mL 40.8 mmol). The resulting mixture was stirred at 80° C. under nitrogen for 1 h and then cooled to rt. The solvents were evaporated under reduced pressure. The residue was dissolved in EtOAc and washed with water and dried over Na2SO4. Evaporation of the solvent gave a white solid which was recrystallized from EtOAc and hexanes to afford the intermediate amide oxime as a white solid (6.93 g, quantitative yield). To a mixture of the intermediate (R)-2-(4-chloro-N-(2-fluoro-4-(N′-hydroxycarbamimidoyl)benzyl)phenylsulfonamido)-5,5,5-trifluoropentanamide (6.93 g, 13.6 mmol) and triethyl orthoformate (6.77 mL, 40.8 mmol) in dichloroethane (30 mL) was added BF3.OEt2 (0.17 mL, 1.36 mmol). The resulting mixture was stirred at 70° C. for 1 h and then cooled to room temperature. Chromatography (silica gel, biotage, 40+M column, 3% to 80% EtOAc in hexanes, 651 mL) provided the title compound as a white solid. (4.9 g, 69.3% yield).

Provenance & Evidence