| Title:  Pantolactone CAS Registry Number:  599-04-2 CAS Name:  Dihydro-3-hydroxy-4H-dimethyl-2(3H)-furanone Additional Names:  pantoic acid g-lactone;  pantoyl lactone;  pantoic lactone;  2,4-dihydroxy-3,3-dimethylbutyric acid g-lactone;  a-hydroxy-b,b-dimethyl-g-butyrolactone Molecular Formula:  C6H10O3 Molecular Weight:  130.14 Percent Composition:  C 55.37%, H 7.75%, O 36.88% Literature References:  A degradation product of pantothenic acid from liver:  Williams, Major, Science 91, 246 (1940).  Important intermediate in the synthesis of pantothenic acid.  May be prepd by condensing isobutyraldehyde with formaldehyde yielding a,a-dimethyl-b-hydroxypropionaldehyde which is condensed with hydrocyanic acid in the presence of calcium chloride to form racemic pantolactone.  Various modifications of this procedure exist:  Glaser, Monatsh. Chem. 25, 46 (1904); Stiller et al., J. Am. Chem. Soc. 62, 1785 (1940); Reichstein, Grüssner, Helv. Chim. Acta 23, 650 (1940); Carter, Ney, J. Am. Chem. Soc. 63, 312 (1941).  Vast patent literature, e.g., Beckmann et al.; Klein, US 2967869 and US 3024250 (1961, 1962, both to Nopco).   Derivative Type:  D(-)-Form  Properties:  Hygroscopic crystals from benzene + petr ether, mp 92°.  [a]D25 -50.7° (c = 2.05 in H2O).  Can be purified by microsublimation. Melting point:  mp 92° Optical Rotation:  [a]D25 -50.7° (c = 2.05 in H2O)   Derivative Type:  L(+)-Form  Properties:  Hygroscopic crystals from benzene, mp 91°.  [a]D25 +50.1° (c = 2 in H2O). Melting point:  mp 91° Optical Rotation:  [a]D25 +50.1° (c = 2 in H2O)   Derivative Type:  DL-Form  Properties:  Hygroscopic rosettes or prisms, mp 80°, bp18 130°.  Freely sol in water.  Sol in ether, benzene, chloroform, alcohol, carbon disulfide. Melting point:  mp 80° Boiling point:  bp18 130°   |