Sodium cyanoborohydride → 4-Bromo-1-[(2-methoxy-5-methylphenyl)sulfonyl]indoline

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Reaction Steps

NaBH3CN (480 mg, 7.63 mmol) was added portionwise, under N2, to ice cold TFA (15 mL). The mixture was stirred for 15 min. and 4-bromo-1-[(2-methoxy-5-methylphenyl)sulfonyl]-1H-indole (645 mg, 1.70 mmol; Intermediate 6) was added in portions. The mixture was allowed to attain rt. and stirred 1.5 h. Additional NaBH3CN (480 mg, 7.63 mmol) was added with continuous stirring 1 h. The reaction mixture was quenched with water (30 mL) and extracted twice with DCM. The DCM layers were combined and extracted with aq. Na2CO3 (˜pH 10). The organic layer was dried, filtered and concentrated to give the title compound (525 mg, 80%) as a yellow viscous oil. MS (ESI+) for C16H16BrNO3S m/z 382 (M+H)+.

Provenance & Evidence