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Functional Development and Reaction Mechanism of Model Oxygenase Complexes

模型加氧酶复合物的功能开发和反应机制

基本信息

批准号：
01550658
负责人：
NISHINAGA Akira
金额：
$ 1.22万
依托单位：
Osaka Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

The following results are obtained in catalytic oxidation processe using cobalt schiff base complexes [Co(SB)] as model oxidoreductases.1. Co^<111>(salpr)(OH), a coordinately saturated hydroxocobalt (III) Schiff base complex, has been found to promote the oxygenation of o-hydroxydibenzoylmethane to flavones and retro-Claisen reaction products (chromanones) in methanol. The results are rationalized by assuming base catalysis of Co(SB)(OH) and provide complexes a new route to the synthesis of chromanones and flavones.2. Coordinately unsaturated Co^<111>(SB)(OH) complexes catalyze the oxygenation of 4-substituted phenylacetylenes in alcohol resulting in highly selective incorporation of dioxygen into the triple bond to give the corresponding acetophenones, mandelic and phenylglyoxylic esters.3. Co(SB) catalyzed oxidation of secondary aromatic amines with t-butyl hydroperoxide results selectively in dehydrogenation to give the corresponding imines. Under the reaction conditions, amines including tertiary amines which are not susceptible to the O_2/Co(SB) oxidation system undergo the oxidation to gives the products similar to those obtained in the P450 system. Proposed mechanism involves electron transfer from the nitrogen atom in the substrate to t-butyloxyl or t-butylperoxyl radical produced in situ from a t-butylperoxocobalt (III) complex intermediate.4. Co(SB) are found to catalyze the oxidation of alkenes with NaOCI to give mainly epoxides together with 1,2-dichloro and chlorohydrin compounds as the primary products. The reaction rate depends on the nature of the cobalt catalyst as well as the structure of the alkene substrate. Proposed mechanism involves rate determining formation of Co^<111>(SB)(OCI)^-, a water soluble green complex followed by homolytic cleavage of the Co-O bond giving rise to C10, which reacts with the substrate to gives the products.

以钴希夫碱配合物[Co(SB)]为模型氧化还原酶，在催化氧化过程中得到了以下结果：Co^<111>(salpr)（OH）是一种配位饱和的羟基钴（III）希夫碱配合物，可以促进邻羟基二苯甲酰甲烷在甲醇中氧化生成黄酮和反claisen反应产物（chromanone）。假设Co(SB)（OH）的碱催化作用对结果进行了合理化，为配合物的合成提供了一条新的途径。配位不饱和Co^<111>(SB)（OH）配合物催化4-取代苯乙炔在醇中的氧化作用，导致高选择性地将二氧结合到三键中，得到相应的苯乙酮、苯乙醛酯和苯乙醛酯。Co（SB）催化过氧化叔丁基氧化仲芳香胺，选择性脱氢生成相应的亚胺。在该反应条件下，不受O_2/Co（SB）氧化体系影响的叔胺等胺类被氧化得到与P450体系相似的产物。提出的机制涉及电子从底物中的氮原子转移到由t-丁基过氧钴（III）络合中间体原位产生的t-丁基氧基或t-丁基过氧基自由基。研究发现，Co（SB）能催化烯烃与NaOCI氧化，主要生成环氧化合物，主要产物为1,2-二氯化合物和氯醇化合物。反应速率取决于钴催化剂的性质以及烯烃底物的结构。提出的机制包括Co^<111>(SB)(OCI)^-的速率决定形成，这是一种水溶性绿色配合物，随后Co- o键的均裂裂解产生C10， C10与底物反应生成产物。