三苯基氧膦和三氟磺酸酐参与的二茂铁咪唑啉合成

二茂铁咪唑啉可以有效地从二茂铁羧酸出发合成．二茂铁羧酸和乙二胺衍生物反应制得的二茂铁酰胺，在三苯基氧膦和三氟磺酸酐所形成的锛盐作用下有效地脱水得到二茂铁咪唑啉化合物．该反应条件温和、反应快、产率高，为二茂铁咪唑啉化合物提供了一个有效的合成方法．     

含二茂铁基聚合物的合成及应用研究进展

二茂铁基聚合物由于具有独特的结构特点,使其在电化学、催化、材料等方面受到了广泛的关注。二茂铁聚合物的种类较多且合成方法多种多样。本文综述了近年来含二茂铁基聚合物的合成及应用。从缩聚、开环聚合和接枝共聚等方面介绍了近年来二茂铁基聚合物的合成方法,讨论了二茂铁基聚合物在电化学、生物材料及其他方面的应用。最后,对二茂铁基聚合物研究和应用中存在的问题及其前景进行了展望。     

双二茂铁基烷酰化衍生物的还原反应

二茂铁甲烷,2,2-双二茂铁丙烷,2,2-双二茂铁基丁烷,2,2-双二茂铁基戊烷与乙酸酐、丙酸酐、正丁酸酐通过傅氏酰基化反应生成一系列双二茂铁基烷的酰化衍生物,再经LiAlH_4还原得到318个相应的α-羟基双二茂铁烷衍生物。文中并对它们的红外光谱和~1H NMR谱性质进行了研究。     

含二茂铁核的硅有机衍生物的合成

合成了一系列含二茂铁核的硅有机衍生物.试图从环戊二烯基三甲基硅烷与FeCl₂在二乙胺存在下制取1,1'-双(三甲基硅烷基)二茂铁,由于Si-C键的断裂,未获预期产物而得二茂铁. 为了合成双有机硅基二茂铁,采用了两种方法.方法之一是从1,1'-二茂铁二钠与相应的三烷基氯硅烷反应制得1,1'-双(三甲基硅烷基)二茂铁、1,1'-双(三丁基硅烷基)二茂铁和1,1'-双(二甲基苯基硅烷基)二茂铁.为了取得单取代硅烷基二茂铁,采用二茂铁锂,但一般得单和双取代衍生物的混合物,它们很难分离;如减少有机氯硅烷用量,则可得纯的单取代乙烯基二乙基硅烷基二茂铁.另一方法是将三甲基-γ-氯丙基硅烷的格氏试剂与二乙酰基二茂铁反应制得含二茂铁核的双叔醇.     

过氧化物模拟酶生物传感器—二茂铁衍生物为介体

本文用三种二茂铁衍生物－双羟基乙基二茂铁、单羟基乙基二茂铁和羧基二茂铁为介体，在过氧化物模拟酶－ｍｅｓｏ－四（４－磺基苯）卟啉锰存在下，检测过氧化氢，以双羟基，单羟基乙基二茂铁为介体时，获得了良好的结果。     

酰基和羟甲基二茂铁衍生物的合成

二茂铁的联苯甲酰化反应及酰基产物的还原反应迄今未见文献报导。我们对此进行了初步研究,合成了联苯甲酰基及羟甲基二茂铁衍生物:对-联苯甲酰二茂铁,1,1’-二-对-联苯甲酰二茂铁和1,1’-二一对-联苯甲醇基二茂铁。     

二茂铁及其衍生物的电化学特性与结构理论研究

研究了二茂铁及其衍生物(甲酰二茂铁,乙酰二茂铁,甲醇二茂铁和乙酸二茂铁)的电化学行为,运用结构理论给出了二茂铁D5点群群轨道能级图与二茂铁衍生物的前线轨道能级图,得出在二茂铁分子结构中1e2(dx2-y2,dxy)与3a1(dz2,4s)分别属于分子前线轨道中的HOMO和LUMO。同时用密度泛函理论(DFT)在LANL2DZ基组水平上对其结构进行了全优化,得到了二茂铁及其衍生物前线最高被占轨道(HOMO)能量值,Fe原子净电荷,对其电化学行为与前线轨道能级相对大小进行了验证。     

二茂铁与DNA作用的表面电化学研究

在研究碳纳米管电极上二茂铁电化学性质的基础上,应用二茂铁修饰电极和DNA修饰电极研究了二茂铁与小牛胸腺DNA的相互作用。结果表明,修饰电极上的二茂铁都呈现一对明显的氧化还原峰,二茂铁修饰电极与DNA的作用表现为氧化还原峰电流减小,与溶液中的两者作用情况类似,而DNA修饰电极与二茂铁的作用则表现为氧化还原峰电流增大。扫描电镜结果也证实了两种修饰电极上的二茂铁与DNA间的作用。此外,还讨论了二茂铁与DNA间的作用模式。     

某些N-芳基-(1′-羧甲基二茂铁基)乙酰胺的合成与表征

以二茂铁为起始原料,经多步反应,合成了1,1’-二茂铁二乙酸酐,后者与取代苯胺反应,合成了十四种新型二茂铁二乙酸单酰胺,并由元素分析、红外光谱和核磁共振氢谱鉴定了化合物的结构。此外,对二茂铁二羧酸单酰胺与过渡金属的螯合反应进行了初步研究。     

某些N-芳基-(1'-羧甲基二茂铁基)乙酰胺的合成与表征

以二茂铁为起始原料,经多步反应,合成了1,1'-二茂铁二乙酸酐,后者与取代苯胺反应,合成了十四种新型二茂铁二乙酸单酰胺,并由元素分析、红外光谱和核磁共振氢谱鉴定了化合物的结构。此外,对二茂铁二羧酸单酰胺与过渡金属的螯合反应进行了初步研究。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.