Triethylamine → 4-(5-Fluoro-2-oxo-2,3-dihydro-benzoimidazol-1-yl)-piperidine-1-carboxylic acid ethyl ester

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Reaction Steps

To a solution of 4-(2-amino-4-fluoro-phenylamino)-piperidine-1-carboxylic acid ethyl ester (0.100 g, 0.36 mmol) and triethylamine (0.110 mg, 1.08 mmol) in methylene chloride (2 mL) at 0° C. was added a solution of diphosgene (0.71 mg, 0.36 mmol) in methylene chloride (4 mL) at room temperature. The reaction mixture was stirred for 18 h then quenched with a saturated aqueous solution of sodium bicarbonate. The organic phase was separated and washed with brine. The organic phase was purified by passing it through a plug of silica gel, using ethyl acetate as the eluent. The filtrate was evaporated, in vacuo, to a residue. The residue was triturated with hexanes/dichlormethane (95:5) and the solid collected by filtration. Vaccum drying yielded 4-(5-fluoro-2-oxo-2,3-dihydro-benzoimidazol-1-yl)-piperidine-1-carboxylic acid ethyl ester (77.8 mg, 71%) as a light tan solid.

Provenance & Evidence