II. CHEMISTRY 489 



and iho y Iroin (he orllio, and llic products had biological activity com- 

 parahlc with that of the respective tocopherols. By degradation studies^^ 

 the structure of 7-tocopherol was confirmed. The suggestions^ that the un- 

 substituted tocopherol be called tocol was generally adopted; a-, /3-, and 

 7-tocopherol are 5,7,8-trimethyl-, 5,8-dimethyl-, and 7,8-dimethyltocol, 

 respectively. A fourth tocopherol, 8-methyl-(5-)tocol, is the principal to- 

 copherol in soybean oil^^ and occurs, normally, in small amounts, in ren- 

 dered hog fat.s^ 



Increased yields from natural sources were obtained by preliminary 

 chromatographic adsorption of unsaponified wheat germ oil and also of 

 the subsequent unsaponifiable portion,^^ as well as by fractional crystalliza- 

 tion.^' Natural a- and 7-tocopherol were both obtained in crystalline form 

 from 2.5% methyl alcohol solution at —35°,*° and their extinction coeffi- 

 cients were not changed significantly by crystallization. /3-Tocopherol could 

 not be crystallized, but crystals of its azobenzene-4-carboxylate were ob- 

 tained as orange plates. The practicability of molecular distillation was 

 demonstrated ;^^"*^ the process will be discussed elsewhere. 



B. DERIVATIVES AND THEIR PHYSIOLOGICAL ACTION 



The always engaging question as to the relation of organic structure to 

 physiological action prompted the preparation of many closely related 

 derivatives of the tocopherols. Various esters were made, some of them 

 beautifully crystalline, including those with fatty acids and with benzoic, 

 succinic, and phosphoric acids. ^-^^ Lower homologs^' and higher homologs 



" A. Jacob, M. Steiger, A. R. Todd, and T. S. Work, /. Chem. Soc. 1939, 542. 



" O. H. Emerson and L. I. Smith, /. A7n. Chem. Soc. 62, 1869 (1942). 



" P. Karrer and H. Fritzsche, Helv. Chim. Acta 21, 1234 (1938). 



" M. H. Stern, C. D. Robeson, L. Weisler, and J. G. Baxter, J. xim. Chem. Soc. 69, 



869 (1947). 

 " J. R. Chipault and W. O. Lundberg, Arch. Biochem. 12, 317 (1947). 

 58 A. R. Moss and J. C. Drunimond, Biochem. J. 32, 1953 (1938). 

 " W. S. Singleton and A. E. Bailey, Oil & Soap 21, 224 (1944). 

 «o C. D. Robeson, /. A7n. Chem. Soc. 65, 1660 (1943). 

 «' F. W. Quackenbush, H. Gottlieb, and H. Steenbock, Ind. Eng. Chem. 33, 1276 



(1941). 

 «2K. C. D. Hickman, Chem. Eng. News 20, 1561 (1942). 

 " M. E. Wall, Ind. Eng. Chem. 41, 1465 (1949). 

 " V. Demote, O. leler, B. H. Ringier, H. Salomon, and P. Karrer, Helv. Chim. Ada 



22, 65 (1939). 

 " P. Karrer, Helv. Chim. Acta 22, 334 (1939). 

 " P. Karrer and G. Bussmann, Helv. Chim. Acta 23, 1137 (1940). 

 "L. I. Smith.W. B.Renfrow,Jr.,andJ.W.Opie,/. Am. Chem. Soc. 64, 1084 (1942). 

 *8 J. G. Baxter, C. D. Robeson, J. D. Taylor, and R. W. Lehman, J. Am. Chem. 



Soc. 65, 918 (1943). 

 «' A. Jacob, F. K. Sutcliffe, and A. R. Todd, J. Chem. Soc. 1940, 327. 



