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

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Reaction Conditions

Reaction Steps

A mixture of 4-bromo-6-chloro-2-methyl-1H-benzo[d]imidazole (3.5 g, 14.26 mmol), p-TsOH.H2O (272 mg, 1.43 mmol), and 3,4-dihydro-2H-pyran (5.9 g, 71.30 mmol) in THF (20 mL) was stirred at 75° C. for 4 h. The reaction mixture was concentrated in vacuo and water was added. The mixture was extracted with EtOAc and the combined extracts dried (MgSO4), filtered, and concentrated in vacuo. The residue was purified by SiO2 chromatography eluting with a DCM:MeOH gradient (0 to 9% MeOH) to afford 4-bromo-6-chloro-2-methyl-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole as a white solid (3.2 g, 69.6%). MS (ESI): m/z=329.0 [M+1]+.

Provenance & Evidence