Diisopropylethylamine → cis(+/-)-4-Chloro-5-ethyl-N-(1-formyl-3-methoxypiperidin-4-yl)-1H-imidazole-2-carboxylic acid amide

Participants

Reaction Steps

tert-Butyl cis(±)-4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-methoxypiperidine-1-carboxylate obtained in Example (1g) (30 mg, 0.08 mmol) was dissolved in methanol (0.5 mL). A 4 N hydrochloric acid/ethyl acetate solution (2.5 mL) was added, and the mixture was stirred at room temperature for 4.5 hours. Following concentration under reduced pressure, the residue was dissolved in DMF (2 mL). Diisopropylethylamine (0.054 mL, 0.31 mmol) was added, and the mixture was stirred at 140° C. using a microwave reactor for one hour. Saline was added to the reaction solution, followed by extraction with ethyl acetate. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. Following concentration under reduced pressure, the residue was purified by reverse phase high performance liquid chromatography (Develosil, 2 cm diameter×10 cm, 0.1% formic acid-containing acetonitrile/water mixed solvent) to obtain 6.6 mg of the title compound as a pale yellow solid (27%).

Provenance & Evidence