Oxamic Acid → N-[2-(3-Cyclopentyloxy-4-methoxyphenyl)ethyl]oxamide

Participants

Reaction Steps

To a suspension of oxamic acid (1.76 g, 20 mmol) in 1,2-dimethoxyethane (75 mL) under an argon atmosphere was added dropwise N-methylmorpholine (2.55 mL, 23 mmol) followed by ethyl chloroformate (2.20 mL, 23 mmol). After stirring for 1 h at room temperature, a solution of 2-(3-cyclopentyloxy-4-methoxy-phenyl)ethylamine (4.65 g, 20 mmol) in 1,2-dimethoxyethane (30 mL) was added over 5 min, and the resulting mixture was stirred for 2 h. Saturated aqueous ammonium chloride was added and the solvent was removed under reduced pressure. The solid residue was dissolved in methanol/methylene chloride, washed successively with water, 10% hydrochloric acid, aqueous sodium bicarbonate and water and dried (potassium carbonate). The solvent was removed in vacuo and the residue was purified by flash chromatography, eluting with 1% i-propanol/methylene chloride to provide the oxamide (1.82 g, 30%): m.p. 175°-175.5° C.

Provenance & Evidence