L-Lysine → 2-Hydroxybutanedioic acid--lysine (1/1)

Participants

Reaction Steps

To an aqueous solution of free L-lysine (200 ml, content of L-lysine: 0.45 mole) is gradually added with stirring L-malic acid (30.16 g, 1/2 mole per 1 mole of L-ysine). The reaction mixture is concentrated under reduced pressure to give a 50% aqueous solution of neutral L-lysine L-malate (liquid volume: about 170 ml). To the resulting solution is gradually added with stirring methanol (200 ml) to precipitate crystals. To a separate vessel containing methanol (470 ml) is added with stirring the above-obtained mixture, and the mixture is stirred at room temperature for about 4 hours. The precipitated crystals are collected by filtration and washed with methanol and air-dried at 40° C. overnight to give a neutral L-lysine L-malate monohydrate (91.9 g, yield: 92.5%) as colorless needle or prismatic crystals. m.p. 216° C. (decomp.)

Provenance & Evidence