MESOXALIC

ACID (dioxymalonic acid), (HO2C)2C(OH)2  or C3H406, is obtained by hydrolysis of alloxan with baryta water (J. v . Liebig, Ann., 1838, 26, p . 298), by warming caffuric acid with lead acetate solution (E . Fischer, Ann., 1882, 215, p . 283), or, from glycerin diacetate and concentrated nitric acid in the cold (E . Seelig, Ber.,1891,'24,p.3471) . It crystallizes in deliquescent prisms and melts with partial decomposition at 119–120° C . It behaves as a ketonic acid, being reduced in aqueous solution by sodium amalgam to tartronic acid, and also combining with phenylhydrazine and hydroxylamine . It reduces ammoniacal silver solutions . When heated with urea to too° ,C. it forms allantoin . By continued boiling of its aqueous solution it is decomposed into carbon dioxide and glyoxylic acid, C2H404 .