Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → (2R)-4-[4-(4-chloro-2,3-difluorophenyl)-2-oxopyridin-1(2H)-yl]-N-hydroxy-2-methyl-2-(methylsulfonyl)butanamide

Participants

Reaction Conditions

Reaction Steps

To a heterogeneous mixture of (2R)-4-[4-(4-chloro-2,3-difluorophenyl)-2-oxopyridin-1(2H)-yl]-2-methyl-2-(methylsulfonyl)-N-(tetrahydro-2H-pyran-2-yloxy)butanamide (14500 mg, 26.94 mmol) in Ethanol (50 mL) and water (100 mL) was added a solution of PPTS (pyridinium p-touluenesulfonate) (7090 mg, 27.9 mmol). The mixture was stirred overnight at 70° C. and a solid formed. The solid was collected via filtration and dried to furnish the title compound as a white solid (5.7 g, 46.9%). The filtrate was concentrated to half the volume and more desired product formed and was collected via filtration to provide additional title compound (3.3 g, 27.1%). LCMS m/z 435.0 (M+1). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.55 (s, 3H) 2.06-2.20 (m, 1H) 2.36-2.45 (m, 1H) 3.08 (s, 3H) 3.67-3.81 (m, 1H) 4.10 (ddd, J=12.20, 11.32, 4.78 Hz, 1H) 6.47 (dt, J=7.17, 1.98 Hz, 1H) 6.57-6.62 (m, 1H) 7.39-7.47 (m, 1H) 7.49-7.57 (m, 1H) 7.77 (d, J=7.22 Hz, 1H) 9.23 (br. s., 1H) 11.08 (s, 1H)19F NMR (376 MHz, DMSO-d6) 6 ppm −138.08 (dd, J=22.56, 7.52 Hz) −139.09 (dd, J=22.56, 7.52 Hz).

Provenance & Evidence