2-Amino-6-chlorobenzoic acid → 4-Chloro-1-(piperidin-4-yl)-1,3-dihydro-2H-benzimidazol-2-one

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Reaction Steps

2-{[1-(tert-butoxycarbonyl)piperidin-4-yl]amino}-6-chlorobenzoic acid Sodium triacetoxyborohydride (3.09 g, 14.6 mmol) was added to a solution of 2-amino-6-chlorobenzoic acid (1.00 g, 5.83 mmol) and N-(t-butoxycarbonyl)-4-piperidone (2.32 g, 11.7 mmol) in dichloroethane (20 mL) at room temperature. After 5 h, the reaction was quenched with saturated aqueous ammonium chloride. This mixture was separated and extracted with ethyl acetate (3×). After drying over sodium sulfate, the solution was filtered and evaporated to give the crude product. This was purified by chromatorgraphy (silica gel, 0 to 15% methanol in methylene chloride gradient elution), which gave the title compound contaminated with some ketone starting material (3.60 g). MS 335.1 (M+1).

Provenance & Evidence