Ammonia → 4-Chloro-1-(piperidin-4-yl)-1,3-dihydro-2H-benzimidazol-2-one

Participants

Reaction Steps

tert-butyl 4-(4-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidine-1-carboxylate from Step B (2.17 g, <6.17 mmol) was dissolved in dichloromethane (10 mL) and trifluoacetic acid (5 mL) was added at room temperature. After 5h, additional trifluoacetic acid (5 mL) was added and the reaction stirred overnight. To this solution was added 2.0 M ammonia in methanol, the mixture was filtered and the volatiles removed in vacuo. The crude product was purified by chromatorgraphy (silica gel, 1 to 25% methanol containing 1% NH3 in methylene chloride gradient elution), which gave the title compound (1.12 g). MS 352.2 (M+1).

Provenance & Evidence