Novel tocopheryl compounds XXV: synthesis and comparison of the para-quinones of all four homologous tocopherol model compounds and their 3,4-dehydro derivatives
Four tocopherol model compounds, the chroman-6-ols (1-4) having the typical substitution pattern of alpha-, beta-, gamma-, and delta-tocopherol (vitamin E), were oxidized to the corresponding para-quinones (5-8), and dehydrogenated to the 2H-chromen-6-ols (17-20) involving initial acetyl protection of the phenolic OH and deprotection as the last step. The chromenols were also converted into the para-quinones (21-24), which existed in the bicyclic hemiketal form, in contrast to the chromanol-derived, monocyclic quinones 5-8, the ketalization behavior agreeing well with computations on the DFT level. (c) 2007 Elsevier Ltd. All rights reserved.
Vitamin E. XLIII.<sup>1</sup> Synthesis of 2,2,7,8-Tetramethyl-6-hydroxychroman and its Behavior upon Oxidation
作者:Lee Irvin Smith、Roy W. H. Tess
DOI:10.1021/ja01237a034
日期:1944.9
A study of the reaction of different phenol substrates with nitric oxide and peroxynitrite
作者:Susana Yenes、Angel Messeguer
DOI:10.1016/s0040-4020(99)00877-7
日期:1999.12
investigated. In general, nitration is the major reaction with peroxynitrite, while reactions with aqueous solutions of nitric oxide led to mixtures of nitro and nitroso derivatives depending upon the phenol. Nitrosation occurs on phenol substrates bearing a free para- position with respect to the OH group with the exception of 1-naphthol, which afforded a 1:1 mixture of the 2- and the 4-nitroso derivatives
E, was chemically combined with differently substituted monofluoro- and difluorophenyl moieties to produce potential antagonists for the human aryl hydrocarbon receptor (AhR). 5-Iodo-γ-tocopherol was a very reliable starting material for the Pd-catalyzed reaction with (fluorophenyl)boronic acids (Suzuki coupling). The ortho- and meta-fluoro-substituted derivatives showed conformational isomerism due
γ-生育酚是通常称为维生素 E 的必需营养混合物的一种成分,它与不同取代的单氟和二氟苯基部分化学结合,以产生人类芳烃受体 (AhR) 的潜在拮抗剂。5-碘-γ-生育酚是 Pd 催化与(氟苯基)硼酸反应(Suzuki 偶联)的非常可靠的起始材料。由于围绕芳族键的旋转受限,邻位和间位氟取代的衍生物显示出构象异构现象。通过NMR光谱研究了这种效应。其中三种衍生物在测定中显示出非常高的效力,是进一步测试的有希望的候选者。