The synthetic form of vitamin D. Prepd from ergosterol by uv irradiation in a suitable solvent: Askew et al., Proc. R. Soc. London B109, 488 (1931/32). The best wavelengths for production of vitamin D2 seem to be from 275 to 300 nm: Knudson, Benford, J. Biol. Chem. 124, 287 (1938); Bunker et al., J. Am. Chem. Soc. 62, 508 (1940). Prepn by electron bombardment of ergosterol using longer waves: AT 119210. Manuf: US 1902785 (1933); US 2030792 (1936); US 1680818 (1928); US 1871136 (1932). Direct total synthesis: B. Lythgoe et al., Tetrahedron Lett. 1977, 3685. Discussion of structural problems: Papers by Askew and Windaus et al., beginning in 1930. Stereochemistry: Crowfoot, Dunitz, Nature 162, 608 (1948); Chem. Ind. (London) 1957, 1149. General review: Inhoffen, Angew. Chem. 72, 875 (1960). A polar, biologically active metabolite of vitamin D2, 25-hydroxyergocalciferol, which is ≈1.5 times more active in curing rickets in rats, has been isolated from pig plasma. See Suda et al., Biochem. Biophys. Res. Commun. 35, 182 (1969); eidem, Biochemistry 8, 3515 (1969).
Vitamin (antirachitic).
Vitamin/Vitamin Source; Vitamin D