Prepd from malic acid: Dessaignes, Ann. 107, 251 (1858). Made by the interaction of monochloroacetic acid and NaCN followed by hydrolysis of the resulting cyanoacetic acid: Weiner, Org. Synth. coll. vol. II, 376 (1943). Prepn from diethyl malonate: Britton, Monroe, US 2373011 (1945 to Dow); from ligneous wastes: Grangaard, US 2928868 (1960 to Kimberly-Clark); from sodium acetate: Normant, Angelo, Bull. Soc. Chim. Fr. 1962, 810. Review: D. W. Hughes in Kirk-Othmer Encyclopedia of Chemical Technology vol. 14 (Wiley-Interscience, New York, 3rd ed., 1981) pp 794-810.