3,4-dihydro-2H-pyran → 5-bromo-6-fluoro-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole

Participants

Reaction Steps

A mixture of 100 (550 mg, 2.57 mmol), TsOH.H2O (50 mg, 0.26 mmol), and 3,4-dihydro-2H-pyran (1.08 g, 12.85 mmol) in THF (10 mL) was heated at reflux overnight. After the solvent was removed in vacuo, the residue was partitioned between DCM (300 mL) and water (100 mL). The organic layer was separated, dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by SiO2 chromatography eluting with a MeOH/DCM gradient (0.5 to 1% MeOH) to afford 817 mg (100%) of 5-bromo-6-fluoro-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole (102) as yellow oil: MS (ESI) m/z=299 [M+1]+.

Provenance & Evidence