N-bromobutanimide → N-{2-Chloro-3-[5-(2-chloro-4-pyrimidinyl)-2-(tetrahydro-2H-pyran-4-yl)-1,3-thiazol-4-yl]phenyl}-2,6-difluorobenzenesulfonamide

Participants

Reaction Steps

Recrystallized NBS (1.56 g, 8.8 mmol) was added to a suspension of N-{2-chloro-3-[(E)-2-(2-chloro-4-pyrimidinyl)-1-hydroxyethenyl]phenyl}-2,6-difluorobenzenesulfonamide (4.02 g, 8.80 mmol) in DMA (15 mL) in an ice-bath. The reaction was immediately removed from the ice bath and allowed to warm to rt over 0.5 h. Tetrahydro-2H-pyran-4-carbothioamide (1.27 g, 8.80 mmol) was added and the reaction warmed in an oil bath (rt to 65° C.). The reaction was diluted with water (100 mL) which caused the precipitation of a yellow solid. The solid was then dissolved by the addition of EtOAc (100 mL) and the phases separated. The aqueous phase was extracted with EtOAc (50 mL). The combined organic phase was filtered through Whatman 1 PS (phase separating) paper and concentrated under vacuum to a crude orange residue. The residue was purified by silica gel chromatography eluting with 0-100% EtOAc/hexanes to give the title compound of Step A as a bright yellow solid (2.56 g; 50.1% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 10.88 (s, 1H), 8.55 (d, J=5.4 Hz, 1H), 7.62-7.74 (m, 1H), 7.48-7.57 (m, 2H), 7.42-7.47 (m, 1H), 7.22 (t, J=9.1 Hz, 2H), 6.54 (d, J=5.3 Hz, 1H), 3.92 (d, J=11.0 Hz, 2H), 3.41-3.51 (m, 2H), 2.03 (br. s., 2H), 1.69-1.83 (m, J=12.1, 12.1, 11.9, 4.2 Hz, 2H).

Provenance & Evidence