Novel tocopherol compounds. III. Reaction of 5a-Bromo-?-tocopherol with Nucleophiles
摘要:
The synthesis of different classes of 5a-substituted tocopherols is described. These compounds are potent antioxidants and highly interesting as vitamin E carriers. The reaction of the readily available 5a-bromo-alpha-tocopherol with alcohols and phenols is shown to produce 5a-alklxy-alpha-tocopherols (3-5, 8, 9) and 5a-aryloxy-alpha-tocopherols (6, 7), respectively, with high yields. 5a-alpha-Tocopheryl esters (10, 11) are prepared by reaction with metal carboxylates. 5a-Bromo-alpha-tocopherol is used as well to introduce tocopheryl groupsinto tertiary amines by quaternization, that renders these compounds (13, 14) soluble in water and in common organic solvents. 5a-Bromo-alpha-tocopherol also reacts as an alkylating agent with sterically hindered phenols in a Friedel-Crafts reaction. Phenols not highly substituted are exclusively alkylated in the para position at room temperature or below, whereas at higher temperature the para- as well as the ortho-alkylated product is observed.
Transformations of chromanol and tocopherol and synthesis of ascorbate conjugates
作者:Martina Lahmann、Joachim Thiem
DOI:10.1016/j.tet.2010.12.066
日期:2011.3
alpha-Tocopherol and as a model compound pentamethylchromanol could be transferred into simple and more complex 5a-ether derivatives including galactopyranose as well as ascorbic acid conjugates. Following elaboration of a glucopyranoside spacer element this could be used for tethering the vitamin E and the vitamin C components to give novel conjugates for subsequent biostudies concerning their proposed synergism of antioxidant properties in tissues. (C) 2011 Elsevier Ltd. All rights reserved.
Oxidations of vitamin E (.alpha.-tocopherol) and its model compound. 2,2,5,7,8-Pentamethyl-6-hydroxychroman. A new dimer
作者:Cacang Suarna、Donald C. Craig、Keith J. Cross、Peter T. Southwell-Keely