Triethylamine → 6-Cyclopropyl-4-fluoro-1-[1-(tetrahydro-2H-pyran-4-yl)-4-piperidinyl]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride

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Reaction Steps

6-Cyclopropyl-4-fluoro-1-(4-piperidinyl)-1,3-dihydro-2H-benzimidazol-2-one hydrochloride (D29, 0.28 mmol, 86 mg), was dissolved in 1,2-dichloroethane (3 ml) and triethylamine (3 eq., 0.83 mmol, 0.086 g), tetrahydro-4H-pyran-4-one (7 eq., 1.99 mmol, 0.2 g) and sodium triacetoxyborohydride (3 eq., 0.83 mmol, 0.052 g) were added at room temperature and the mixture was stirred at room temperature for one overnight. The reaction mixture was quenched with NaHCO3 (saturated solution) and diluted with dichloromethane, then the two phases were separated by hydrophobic filter and the aqueous was washed with dichloromethane again. The organic phases were combined and the solvent was evaporated to afford the crude product which was purified by chromatography (methanol-NH3-dichloromethane) to afford the free base of the title compound, 100 mg, 98%, M++H=360. This material was dissolved in methanol (2 ml) and HCl (3 eq., 0.046 ml from a 1M solution in diethyl ether) was added at room temperature and the mixture was stirred at room temperature for 5 minutes. The solvent was subsequently evaporated to afford the title compound, 90 mg, 82%.

Provenance & Evidence