ASPARAGINE

asparagine, c4h3n2o3, a naturally occurring base, found in plants belonging to the natural orders leguminosae and cruciferae. it occurs in two optically active forms, namely, as laevo-asparagine and dextro-asparagine. laevo-asparagine was isolated in 1805 by l.n. vauquelin. a. piutti (_gazz. chim. ital._, 1887, 17, p. 126; 1888, 18, p. 457) synthesized the asparagines from the monomethyl ester of inactive aspartic acid by heating it with alcoholic ammonia. in this way a mixture of the two asparagines was obtained, which were separated by picking out the hemihedral crystals. hooc.ch.nh2ch2.cooc2h5 + nh3 = c2h5oh + hooc.ch.nh2.ch2.conh2. laevo-asparagine is slightly soluble in cold water and readily soluble in hot water. it crystallizes in prisms, containing one molecule of water of crystallization, the anhydrous form melting at 234-235 deg. c. nitrous acid converts it into malic acid, hooc.choh.ch2.cooh. it is laevo-rotatory in aqueous or in alkaline solution, and dextro-rotatory in acid solution (l. pasteur, _ann. chim. phys._, 1851 [2], 31, p. 67). dextro-asparagine was first found in 1886 in the shoots of the vetch (piutti). it forms rhombic crystals possessing a sweet taste. it is dextro-rotatory in aqueous or alkaline solution, and laevo-rotatory in acid solution. hydrolysis by means of acids or alkalis converts the asparagines into aspartic acid; whilst on heating with water in a sealed tube they are converted into ammonium aspartate. the constitution of the asparagines has been determined by a. piutti (_gazz. chim. ital._, 1888, 18, p. 457).