One of the naturally occurring forms of vitamin E, q.v. Isoln from wheat bran: Green et al., J. Sci. Food Agric. 6, 274 (1955); Green et al., Chem. Ind. (London) 1960, 73. Structure: Green et al., J. Chem. Soc. 1959, 3362. Attempt at synthesis: McHale et al., ibid. 1963, 784. Review: M. Kofler et al., “Physicochemical Properties and Assay of the Tocopherols” in R. S. Harris, I. G. Wood, Vitam. Horm. 20, 407-439 (1962). Synthesis of all-trans-form: Schudel et al., Helv. Chim. Acta 46, 2517 (1963).