6-Aminohexanoic Acid → 6-Maleimidohexanoic acid

Participants

Reaction Steps

A solution of 4.2 g (32.3 mmol) of 6-aminocaproic acid in 163 ml of saturated sodium bicarbonate solution is treated at 0° C., with vigorous stirring, with 5 g (32.3 mmol) of N-carbomethoxymaleimide. After 1 hour, the solution is diluted with 256 ml of water and stirred at room temperature for 1 hour. The pH of the solution (8.2) is then brought to 6.4 by adding concentrated sulfuric acid. The solution is then concentrated to 100 ml and acidified to pH 2 by adding 1 M sulfuric acid, and is extracted three times with ethyl acetate. The organic phases are combined, dried over anhydrous sodium sulfate and evaporated to dryness under vacuum. The residue is purified by chromatography on a silica column (elution: chloroform/acetic acid, 95:5). In this manner, 4.7 g of N-maleoyl-6-aminocaproic acid are obtained.

Provenance & Evidence