Trifluoroacetic acid → N-{2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}cyclopropanesulfonamide

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Reaction Steps

2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-amine (300 mg, 0.934 mmol) and DMAP (115 mg, 0.934 mmol) were dissolved in 10 mL of DCM. Cyclopropanesulfonyl chloride (170 mg, 1.21 mmol) was added and the solution was stirred at rt for 2 h. The solution was washed with saturated aqueous NaHCO3 solution, brine and dried over anhydrous MgSO4. The product was purified by silica gel flash chromatography using EtOAc as eluent. The fractions were concentrated and the residue was dissolved in 25 mL of MeOH. TFA (0.143 mL, 1.86 mmol) was added dropwise and the solution was stirred at rt for 30 min. The solvent was evaporated and the product was precipitated in ether affording the title compound as its corresponding TFA salt. Yield: 390 mg (77%). 1H NMR (400 MHz, METHANOL-D4) δ 0.91-0.97 (m, 2 H), 1.02-1.08 (m, 2 H), 1.48-1.60 (m, 2 H), 1.65 (s, 9 H), 1.67-1.75 (m, 3 H), 1.75-1.82 (m, 1 H), 2.00-2.10 (m, 2 H), 2.18-2.28 (m, 1 H), 2.53-2.61 (m, 1 H), 4.50 (d, J=7.42 Hz, 2 H), 7.42 (dd, J=8.98, 2.15 Hz, 1 H), 7.74 (d, J=1.56 Hz, 1 H), 7.85 (d, J=8.79 Hz, 1 H); MS (ESI) (M+H)+ 426.0; Anal. Calcd (%) for C21H29N3O2SF2+1.0 TFA; C, 51.20; H, 5.60; N, 7.79. Found: C, 51.38; H, 5.66; N, 7.56.

Provenance & Evidence