SYNTHESIS AND INTERCONVERSION BY HYDROGEN-EXCHANGE OF ISOMERIC QUINHYDRONES
SYNTHESIS AND INTERCONVERSION BY HYDROGEN-EXCHANGE OF ISOMERIC QUINHYDRONES
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DOI：
10.1021/jo00445a018
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发表时间：
1977-01-01
影响因子：
3.6
通讯作者：
PAUL, IC
中科院分区：
文献类型：
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作者：
DESIRAJU, GR;CURTIN, DY;PAUL, IC
异构的醌氢酮，2-苯基醌/2-（4 ′-氯苯基）氢醌（1：1）（1a）和2-（4 ′-氯苯基）-醌/2-苯基氢醌（1：1）（1b），已被制备为结晶固体，并显示当保持在固态时，即使在高达140 ℃的温度下也能抵抗氧化还原（氢交换）过程的相互转化。有人建议，这些不对称取代的配合物是惰性的氧化还原相互转化，因为稳定的氢键和电荷转移力的组合。用核磁共振波谱法研究了溶液中若干醌-对苯二酚对的氧化还原平衡速率的半定量测量，作为合理选择上述醌氢酮对的基础。苯醌和对苯二酚的分子络合物（1：1）（醌氢酮）长期以来被认为是稳定的固体，然而，在溶液中分离成它们的组分。3.利用醌和对苯二酚环上不同取代基的存在，可以制备同分异构的醌氢酮，并对氘和碳14标记的化合物进行了研究，作为研究这类化合物在溶液中氧化还原相互转化的一种方法。[4]在其他一些试图制备取代的醌氢酮的异构体对的情况下，由于溶液中氧化还原的快速相互转化，加上缺乏适当的表征方法，导致了令人困惑的结果。
Isomeric quinhydrones, 2-phenylquinone/2-(4'-chlorophenyl) hydroquinone (1: 1)(la) and 2-(4'-chlorophenyl)-quinone/2-phenylhydroquinone (1: 1)(lb), have been prepared as crystalline solids and shown to resist interconver-sion by a redox (hydrogen exchange) process even at temperatures as high as 140 C when kept in the solid state. It is suggested that these unsymmetrically substituted complexes are inert to oxidation-reduction interconversions because of a stabilizing combination of hydrogen bonding and charge-transfer forces. A semiquantitative survey of the rates in solution of the redox equilibration of a number of quinone-hydroquinone pairs has been studied by NMR spectroscopy as the basis for the rational selection of the pair of quinhydrones described above.Molecular complexes (1: 1)(quinhydrones) of benzoqui-nones and hydroquinones have long been known as stable solids which, however, in solution separate into their components. 3 The possibility of preparing isomeric quinhydrones by virtue of the presence of different substituents on the quinone and hydroquinone ring has been recognized, and in-vestigations of deuterium-and carbon-14-labeled compounds have been carried out as a method of studying the redox interconversions in solution of such compounds. 4 In other cases where preparation of isomeric pairs of substituted quinhydrones has been attempted, the rapid redox interconversion in solution coupled with a lack of adequate methods of char-acterization has led to confusing results.® Neverthelesscrystals of unsymmetrically substituted complexes of this type as, for