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

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Reaction Conditions

Reaction Steps

To a solution of 5-bromo-4-methyl-1H-benzo[d]imidazole (1.0 g, 4.74 mmol, CASRN 952511-48-7) and 3,4-dihydro-2H-pyran (2.0 g, 23.70 mmol) in THF (10 mL) was added p-TsOH.H2O (90 mg, 0.47 mmol). The mixture was heated at 80° C. overnight, cooled and the solvent was 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 to dryness in vacuo. The crude product was purified by SiO2 chromatography eluting with a petroleum ether/EtOAc gradient (10 to 50% EtOAc) to afford 800 mg (57%) of 5-bromo-4-methyl-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole (254) as light yellow solid: MS (ESI) m/z=295.1 [M+1]+.

Provenance & Evidence