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3-氧代甾族化合物经过脱氢所产生的在生物学上占重要地位的1,4-二烯-3-酮,多年来一直是一个令人十分注意的研究领域。近年来,作者曾提出用苯亚硒酐(BSA)试剂很方便地达到这一目的,它具有比常用的二氯二氰苯醌(DDQ)、二氧化硒或溴化-脱溴化氢等方法某些优点。然而,苯硒酸的形成或在消除反应中所产生酐的其它还原形式,会带来不必要的副反应,特别是在反应时间过长时更为严重。根据二苯二硒能快速而有效地再被氧化这一事实,采用了一个催化循环体系后,则完全避免上述缺点。现较详细地介绍该系统的发展过程。最初,我们研究了各种N-氧化物中的氧
The biologically predominant 1,4-dien-3-one produced by dehydrogenation of 3-oxo-steroids has been a field of considerable interest for many years. In recent years, the authors have proposed to achieve this object conveniently with benzilic acid selenide (BSA) reagent, which has advantages over conventional DDQ, selenium dioxide or brominated-dehydrobromide Some advantages of the method. However, the formation of benzene selenate or other reductive forms of anhydrides produced in the elimination reaction can lead to undesirable side reactions, especially when the reaction time is too long. According to the fact that diphenylsalicyane can be reoxidized rapidly and efficiently, the use of a catalytic recycle system completely obviates the above drawbacks. The development of the system is now described in more detail. Initially, we investigated the oxygen in various N-oxides