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. The residue was diluted with water and extracted with EtOAc. The combined extracts were 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