[Br:1][C:2]1[CH:10]=[C:9]([F:11])[C:5]2[NH:6][CH:7]=[N:8][C:4]=2[CH:3]=1.[O:12]1[CH:17]=[CH:16][CH2:15][CH2:14][CH2:13]1.CC1C=CC(S(O)(=O)=O)=CC=1.O>C1COCC1>[Br:1][C:2]1[CH:10]=[C:9]([F:11])[C:5]2[N:6]([CH:13]3[CH2:14][CH2:15][CH2:16][CH2:17][O:12]3)[CH:7]=[N:8][C:4]=2[CH:3]=1To a solution of 5-bromo-7-fluoro-1H-benzo[d]imidazole (650 mg, 3.02 mmol, CASRN 1197944-33-2) and 3,4-dihydro-2H-pyran (1.27 g, 15.12 mmol) in THF (10 mL) was added p-TsOH.H2O (58 mg, 0.30 mmol). The reaction was stirred at 80° C. overnight, cooled and the solvent removed in vacuo. The residue was diluted with DCM (100 mL) and water (50 mL). The organic layer was separated, dried (MgSO4), filtered and concentrated in vacuo. The crude product was purified by SiO2 chromatography eluting with a petroleum ether/EtOAc gradient (10 to 50% EtOAc)) to afford 580 mg (64%) of 5-bromo-7-fluoro-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole (266) as yellow solid: MS (ESI) m/z=299.1 [M+1]+.
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