模拟细胞色素P-450的仿生氧化反应的研究 T.氯合5,10,15,20-四苯基卟吩合铁(III)催化下不同亚碘酰芳烃及其衍生物的结构对环己烷充氧化反应的影响

在氯合5,10,15,20-四苯基卟吩合铁(Ⅲ)[TPPFe(Ⅲ)Cl]催化下,带有不同取代基的亚碘酰苯和亚碘酰苯的衍生物作充氧化剂对环己烷进行了仿生单充氧化反应的研究.取代亚碘酰苯中对位取代基的电子效应和间位取代基的电子及立体效应对氧化产物环己醇的产率有良好线性相关性.亚碘酰苯的衍生物苯亚碘酸二醋酐与苯亚碘酸单对甲苯磺酸酐对环己烷的充氧化能力和邻、间、对亚碘酰苯甲酸与邻亚碘酰苯甲酸酯相似,环己醇产率接近零.从而提出亚碘酰苯甲酸及邻亚碘酰苯甲酸酯存在分子内或分子间I(OH)OCO成键结构的论点.     

模拟细胞色素P-450的仿生氧化反应研究 II.氯合,-5,10,15,20-四苯基卟吩合锰(III)催化下亚碘酰芳烃及其衍生物的结构对环已烷羟化及氯化反应的影响

在氯合,-5,10,15,20-四苯基卟吩合锰(Ⅲ)[TPPMn(Ⅲ)Cl]催化下,带有不同取代基的亚碘酰苯对环己烷的充氧化反应与TPPFe(Ⅲ)Cl催化的结果不同,取代基的电子效应和立体效应对羟化产物(环己醇)的产率无线性相关性,而对氯代产物(氯代环己烷)的产率有良好线性相关性.比较了苯亚碘酸二醋酐、苯亚碘酸单对甲苯磺酸酐和邻、间、对亚碘酰苯甲酸及邻亚碘酰苯甲酸酯的结构对环己烷充氧化反应的影响,表明了它们的结构相似性.     

模拟细胞色素P－450的仿生氧化反应的研究（Ⅴ）──氯合5，10，15，20－四取代苯基卟吩合铁（Ⅲ）中取代基对催化环己烷单加氧反应的影响

系统地考察了一系列氯合５，１０，１５，２０－四取代苯基卟吩合铁（Ⅲ）Ｔ（Ｒ－Ｐ）ＰＦｅ（Ⅲ）Ｃｌ（Ｒ＝ｏ，ｍ，ｐ－Ｍｅ，ＭｅＯ，Ｃｌ，Ｂｒ，Ｉ，ＮＯ２，ｏ－ｔ－Ｂｕ，ｐ－ｔ－Ｂｕ，ｏ－ＮＨ２，Ｅｔ，ｉ－ｐｒ）作模拟酶单加氧催化剂，以亚碘酰苯作供氧体对环己烷进行羟化反应时的取代基效应。环己醇产率随取代基Ｒ的拉电子性增强而提高，对位取代基常数σｐ与环己醇产率间存在Ｈａｍｍｅｔｔ线性相关式：１ｇ（ＹＲ／ＹＨ）＝３．２σｐ－０．０３。邻位取代基的立体效应也增加环己醇的产率。     

模拟细胞色素P—450的仿生氧化反应的研究（Ⅴ）：氯合5,10,15,…

系统地考察了一系列氯合５，１０，１５，２０－四取代苯基卟吩合铁（Ⅲ）Ｔ（Ｒ－Ｐ）ＰＲｅ（Ⅲ）Ｃｌ（Ｒ＝ｏ，ｍ，ｐ－Ｍｅ，ＭｅＯ，Ｃｌ，Ｂｒ，Ｉ，ＮＯ２，ｏ－ｔ－Ｂｕ，ｐ－ｔ－Ｂｕ，ｏ－ＮＨ２，Ｅｔ，ｉ－Ｐｒ）作模拟酶单加氧催化剂，以亚碘酰苯作供氧体对环己烷进行羟化反应时的取代基效应，环己醇产率随取代基Ｒ的拉电子性增强而提高，对位取代基数σｐ与环己醇产率间存在Ｈａｍｍｅｔｔ线性相关式：ｌｇ（ＹＲ／Ｙ     

有机亚碘酰化合物的研究(Ⅱ)——羧基及酯基取代亚碘酰芳烃的结构与性能的研究

本文对邻亚碘酰肉桂酸、邻亚碘酸苯乙酸、邻亚碘酰苯甲酸及其酯和间亚碘酰笨甲酸进行了波谱分析,认为它们都存在着分子内成环结构。     

甲烷单加氧酶的化学模拟: 酚氧双羧酸根桥联Fe~2(III)和 Mn~2(III)配合物合 成、表征及催化性能

合成表征了酚氧、双羧基桥联双组氨酸的手性双铁核配合物和双锰核配合物,研究了它们催化亚碘酰苯对烯烃的环氧化反应和对环烷烃的羟化反应。结果表明这种Fe~2(III)和Mn~2(III)配合物均是有效的甲烷单加氧酶(MMO)模型化合物,其中Fe~2配合物能较好地再现MMO的某些性质,如电子光谱等。Fe~2配合物催化苯乙烯环氧化反应生成环氧苯乙烷的产率为840%(以催化剂计),且R-(+)-构型对映体过量(e.e.)达45.4%。相庆的Mn~2配合物则以7080%产率给出环氧苯乙烷,R-(+)-构型对映体过量51.6%。Mn~2配合物还能够催化环己烯和环己烷的氧化反应,产物及其分布分别为环氧环己烷3880、环乙烯醇603、环己烯酮189和环己醇1053、环己酮639%(以催化剂计)。EPR研究表明MM=O是反应的活性中间体。     

甲烷单加氧酶的化学模拟: 酚氧双羧酸根桥联Fe~2(III)和 Mn~2(III)配合物合 成、表征及催化性能

合成表征了酚氧、双羧基桥联双组氨酸的手性双铁核配合物和双锰核配合物,研究了它们催化亚碘酰苯对烯烃的环氧化反应和对环烷烃的羟化反应。结果表明这种Fe~2(III)和Mn~2(III)配合物均是有效的甲烷单加氧酶(MMO)模型化合物,其中Fe~2配合物能较好地再现MMO的某些性质,如电子光谱等。Fe~2配合物催化苯乙烯环氧化反应生成环氧苯乙烷的产率为840%(以催化剂计),且R-(+)-构型对映体过量(e.e.)达45.4%。相庆的Mn~2配合物则以7080%产率给出环氧苯乙烷,R-(+)-构型对映体过量51.6%。Mn~2配合物还能够催化环己烯和环己烷的氧化反应,产物及其分布分别为环氧环己烷3880、环乙烯醇603、环己烯酮189和环己醇1053、环己酮639%(以催化剂计)。EPR研究表明MM=O是反应的活性中间体。     

模拟细胞色素P-450的仿生氧化反应研究 Ⅲ.有关用TPPFe(Ⅲ)Cl及TPPMn(Ⅲ)Cl催化的环己烷充氧化反应机理的初步探讨

在TPPFe(III)Cl或TPPMn(III)Cl催化下烷烃用亚碘酰苯充氧化成醇的反应作为细胞色素P-450的模拟酶催化氧化反应已广为人知,有关这一反应的机理虽已有不少研究但迄今未有一致看法,具有代表性的有Groves等提出的通过中间体TPPM(V)Cl(1)或TPPM(IV)Cl(2)(M=Fe,Mn)再与烷烃进一步发生游离基反应的机理和Hill等提出的M=Mn时经中间体[Ar(Cl)IOMn]_2O(3)再与烷烃反应的机理。我们曾用带不同取代基的亚碘酰苯在TPPFe(III)Cl及TPPMn(III)Cl催化下对环己烷进行充氧化反应,发现二种催化     

乙酰葡萄糖氧代金属卟啉的合成及其对环己烷羟基化反应的催化作用

由吡咯和葡萄糖取代苯甲醛直接缩合制备了两种葡萄糖取代卟吩:四(邻位乙酰葡萄糖氧代苯基)卟吩和四(间位乙酰葡萄糖氧代苯基)卟吩,进一步金属化合成了4种葡萄糖金属卟啉:氯化四(邻位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(间位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(邻位四乙酰葡萄糖氧代苯基)卟吩合锰和氯化四(间位乙酰葡萄糖氧代苯基)卟吩合锰.它们的结构由紫外-可见光谱、核磁共振和元素分析证实.研究了这些葡萄糖取代金属卟啉对亚碘酰苯常温常压下氧化环己烷反应的催化作用.研究结果表明,4种糖基金属卟啉催化下的环己烷反应产率和反应速率都比一般金属卟啉高.反应动力学分析表明,在常温常压下,糖基金属卟啉催化下的环己烷氧化反应具有酶催化反应的动力学关系.     

细胞色素P-450模拟体系的活性中间体-氧配位铬(V)四苯基卟啉 配合物的分离、 表征和氧化反应

氮气保护下二氯甲烷中铬(III)四苯基卟啉衍生物在-40℃与亚碘酰苯反应,分离得氧配位铬(V)四苯基卟啉配合物:O=Cr(V)TPP(Cl)PhI,O=Cr(V)TPP(N~30PhI,O=Cr(V)TPP(p-CH~3O-C~6H~4O)(1/2)PhI。已经元素分析、可见、红外、顺磁、核磁和质谱法结构表征。这些配合物能氧化苯乙烯,环己醇,环己烯和环己烷,可作为细胞色素P-450模拟体系的活性中间体。     

Substituent effects on chloro meso-tetra-ortho-alkylphenylporphinato iron catalyzed biomimetic oxidation of cyclohexane

Six sterically hindered chloro meso-tetra-ortho-alkylphenylporphinato irons (T(o-R)PPFe(HI)Cl, R = Me, Et, n-Pr, i-Pr, n-Bu, t-Bu) were synthesized and used to catalyze the monooxygenation of cyclohexane with PhIO. Both the yields of cyclohexanol and the relative rates of monooxygenation of cyclohexane catalyzed by T(o-R)PPFe(III)Cl were higher than those of TPPFe(III)Cl respectively. The order of the yields(%) of cyclohexanol and the rate of cyclohexanol formation in the monooxygenation of cyclohexane catalyzed by T(o-R)PPFe(III)Cl for the different substituents are: i-Pr(58) > Et(57) > n-Pr(52) > Me(51) > n-Bu(48) > t-Bu(46) > H(35) and i-Pr > Et > t-Bu > n-Pr > Me > n-Bu > H respectively. The special steric effect on the catalytic character of these different alkyl substituents in T(o-R )PPFe(III)Cl is proposed on the basis of the results.     

手性过渡金属(Mn, Co, Ni)-Salen配合物催化NaOCl不对称环氧化苯乙烯的反应研究

本文论述了由手性1, 2-二苯基乙二胺与适当取代的邻羟基苯甲醛生成的希佛碱作为过渡金属Co(II)、Ni(II)、Mn(II)的配体合成的6种过渡金属-Salen配合物在NaOCl下均相催化苯乙烯不对称环氧化反应的效果。对环氧化反应进行控制性研究, 我们发现环氧化反应与中心金属离子的相关性可能主要源于配体结构、金属离子的选择及二者结合形成的配合物的空间构型。好的不对称环氧化反应催化剂要求中心金属离子具有适当的氧化还原电位, 对底物烯烃因其取代基的大小, 催化剂结构的空间构型应有好坏之分, 我们得到的循环伏安数据及实验结果部分说明这一点。同时对手性镍(II)-Salen及手性锰(III)-Salen配合物的催化反应机理配合实验现象分别作出假设, 都经过自由基历程, 但却是截然不同的活性氧化物种, 同时, 由于起主要作用的不对称诱导因素不同, 不对称诱导方向有异。对同一催化剂在不同pH值下起作用的活性氧化物种类别也可能不同。     

区域选择性合成2-硝基-5, 10, 15, 20-四芳基金属卟啉

研究了以硝酸盐为硝化剂与中位四芳基金属卟啉反应、选择性合成2-硝基-5,10,15,20-四芳基卟啉的方法,发现配位金属离子、中位苯环上的取代基对反应产率和时间有明显的影响,当金属离子为铜、镍时,可得定量的2-硝基卟啉,为锌时,完成反应的时间延长,反应产率迅速下降。推电子的甲氧基能加快反应的进行,吸电子的氯原子则延缓反应的进行。讨论了金属离子和取代基团对反应影响的原因。     

Synthesis of para- or ortho-substituted triarylbilindiones and tetraarylbiladienones by coupled oxidation of tetraarylporphyrins

Coupled oxidation of [tetraarylporphyrinato]iron(III) chloride carrying substituents in the ortho or para positions was performed by allowing the iron porphyrin to react with dioxygen, ascorbic acid, and pyridine to give biladienone as the major product and bilindione as a minor one. Efforts to find reaction conditions and workup procedures to obtain bilindione improved the yields of triarylbilindiones ranging between 2% and 19%. Electron-withdrawing substituents in the para position on the aryl groups increased the selectivity of bilindione relative to biladienone: the isolated yields of bilindione and biladienone were 2% and 85% (OMe), 6% and 44% (COOMe), and 7% and 28% (CN), respectively. Electronic effects of substituents affected both isolation procedures and the spectroscopic properties of bilindiones. Tri(4-methoxyphenyl)bilindione showed a red-shifted electronic absorption compared to unsubstituted and 4-methoxycarbonyl substituted analogues. This was ascribed to the destabilization of the HOMO-1 level by the methoxy groups.     

Porphyrins with exocyclic rings. Part 21: Influence of pyrrolic and carbocyclic ring alkyl substituents on the synthesis of porphyrins bearing six-membered exocyclic rings

A series of 5-substituted 4,5,6,7-tetrahydroindoles were prepared by reacting 4-substituted cyclohexanones with phenylhydrazones derived from esters of acetoacetic acid under Knorr-type reaction conditions. Related 6,6-dimethyltetrahydroindoles were also prepared by reacting dimedone with oximes by the Knorr pyrrole syntheses, followed by selective reduction of the remaining ketone moiety with diborane. The substituted tetrahydroindoles were regioselectively oxidized with lead tetraacetate to give the related 7-acetoxy derivatives, and these reacted with 5-unsubstituted pyrrole esters to give pyrrolyltetrahydroindoles. In one case, a bromo substituent was used to protect the β-position of the pyrrole reactant. Cleavage of the benzyl ester protective groups with hydrogen over Pd/C, which also removes the bromo-protective group, gave four dipyrrole carboxylic acids. These were condensed with a dipyrrylmethane dialdehyde using the MacDonald ‘2+2’ condensation to give substituted porphyrins with six-membered exocyclic rings. These structures are useful for comparison to porphyrin samples found in organic-rich sediments such as oil shales and petroleum. The presence of methyl substituents on the six-membered ring for the tetrahydroindole precursors slightly decreases the yields for porphyrin synthesis, and this effect is enhanced when the system becomes more sterically crowded due to the presence of an ethyl group of the adjacent pyrrole ring. 5-Alkyl substituted tetrahydroindoles were also converted to tetrapropanoporphyrins via a cyclotetramerization procedure. The alkyl substituents again decreased the yields, although 5-alkyl substituents were found to have a far less deleterious effect than 6-alkyl groups. In addition to providing samples to help assign the vibrational spectra of geoporphyrin samples, these results demonstrate that highly substituted porphyrin systems can be prepared from tetrahydroindole derivatives.     

Correlation analysis of substituent effects on the acidity of benzoic acids by the AM1 method

Theoretical analysis of the electronic effect of aromatic substituents was done with the use of the AM1 computational procedure. The gas-phase acidity of substituted benzoic acids was linear with the difference in the heat of formation between corresponding benzoic acids and benzoate anions, the energy of the highest occupied molecular orbital, and the net charge on the acidic oxygen atoms of the corresponding benzoate anions. The Hammett σ constant was linearly correlated with the net charge on the atoms of the acid moiety of substituted benzoic acids. The AM1 computational procedure satisfactorily reproduced the electronic properties of a wide variety of substituents.     

Regioselectivity of olefin oxidation by iodosobenzene catalyzed by metalloporphyrins : control by the catalyst

The regioselectivity of the oxidation of three monosubstituted olefins, 6-phenoxyhex-1-ene, hex-1-ene and styrene, by iodosobenzene in the presence of various Fe-, Mn- or Cr-tetraaryl-porphyrins, was studied. It was found that, besides epoxides, known products from such systems, allylic alcohols and aldehydes were formed, the latter not being derived from the corresponding epoxides. The relative importance of these reactions greatly depends upon both the metal and porphyrin constituents of the catalyst. More particularly, the competition between epoxidation and allylic hydroxylation can be efficiently controlled by non-bonded interactions between the olefin and porphyrin substituents. No hydroxylation of the aromatic rings and no oxidative dealkylation of the ether function was detected.     

Conversions of 2-thioxo-1,3-dithiol-4,5-dicarboxylic acid dimethyl ester — The path to a new heterocyclic system, (4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2,5,7-trione and 5,6-dimercaptouracil derivatives

The conversions of 2-thioxo-1,3-dithiol-4,5-dicarboxylic acid methyl ester into anhydride, mono- and diamide, and monoamide methyl ester were demonstrated. The new heterocyclic system, (4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2,5,7-trione, was obtained by oxidative rearrangement-cyclization of 2-oxo-1,3-dithiol-4,5-dicarboxylic acid diamide with phenyliodosyl(hydroxy)tosylate and used to synthesize previously unknown 5,6-dimercaptouracil derivatives, including nickel dithiolene complex.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1275, September, 1992.     

Substituent effects of phosphonate groups electronic repartition of π-conjugated ferrocene analogues of stilbene

The synthesis of para-substituted ferrocene analogues of stilbene was performed by using the Heck reaction, starting from vinylferrocene. The variation of the electronic density of these compounds with the electronic withdrawing strength of the substituents was studied using ¹³C NMR spectroscopy, absorption spectra and cyclic voltammetry. The correlation of Hammett constants with the redox properties of the substituted compounds using Nagy's method allowed us to revisit the determination of the Hammett constants of diethyl phosphonate ester and phosphonic acid substituents. Our measurements were in agreement with the literature except for the diethyl phosphonate group.     

Regioselective Arene Functionalization: Simple Substitution of Carboxylate by Alkyl Groups

Arenes with various alkyl side‐chains were synthesized in high yields and excellent regioselectivities. Starting from toluic and naphthoic acids, the carboxylate group was conveniently substituted by alkyl halides by Birch reduction and subsequent decarbonylation. The method is characterized by inexpensive starting materials and reagents, and methylation of arenes was realized. Besides simple alkyl substituents, the scope of arene functionalization was extended by benzyl, fluoro, amino, and ester groups. We were able to control the alkylation of 1‐naphthoic acid during Birch reduction by the addition of tert‐butanol. This allowed the regioselective synthesis of mono and bis‐substituted naphthalenes from the same starting material.