苯二酰异羟肟酸及癸二酰异羟肟酸的合成和抑菌活性

苯二酰异羟肟酸及癸二酰异羟肟酸的合成和抑菌活性;大肠杆菌;金黄色葡萄球菌     

二羟乙基二硫代氨基甲酸铋配合物的合成、晶体结构及杀菌活性

二硫代氨基甲酸盐;二羟乙基二硫代氨基甲酸铋配合物的合成、晶体结构及杀菌活性     

2,5-二甲氧基苯胺的乳液聚合及聚合物结构表征

2;5-二甲氧基苯胺的乳液聚合及聚合物结构表征     

六芳基二咪唑类化合物的合成及光致变色性能

六芳基咪唑;六芳基二咪唑类化合物的合成及光致变色性能     

1,3-二硫环已烷系列衍生物的合成及表征

1;3-二硫环已烷系列衍生物的合成及表征;Bunte Salt法; 合成; 二硫环己烷; 香料; 表征     

2,5-二辛氧基聚对苯的合成及表征

蓝色电致发光;2;5-二辛氧基聚对苯的合成及表征     

燃烧排放物中的有毒二噁碤及类二噁碤多氯联苯

本文评述了国内外对二噁碤的研究成果及动向,介绍了二噁碤中的有毒同族体及其毒性当量计算、准确的分析方法、燃烧过程中二噁碤的光降解行为及其降解产物、类二噁碤多氛联苯等内容,引述了90多篇最新的文献及有关图表。     

聚8,8＇-二羟基-5,5＇-偶氮苯二喹啉金属螯合物的合成及荧光性质

羟基喹啉;自组装薄膜;聚8;8＇-二羟基-5;5＇-偶氮苯二喹啉金属螯合物的合成及荧光性质     

二维大分子的构象及凝聚态调控

近年来,二维大分子蓬勃发展,已经成为继经典线形与支化拓扑大分子之后的一个重要分支.二维大分子不但补全了经典高分子科学中缺失的二维分子维度,而且成为具有广泛且重要应用前景的材料新体系,将延续高分子科学在国民经济生产生活中的重要作用.类比成熟的线形高分子系统,深入理解二维大分子的构象与凝聚态并建立精确的材料结构调控方法是其发展的基础,目前仍然处于起步阶段.本文以我们课题组的研究工作为主线,以氧化石墨烯为二维大分子理想模型,总结了二维大分子构象行为与凝聚态结构调控的研究思路与进展.简要回顾了二维大分子构象的研究历史,介绍了构象行为规律、液晶凝聚态以及固态凝聚结构调控方法的系列新进展,并对未来二维大分子构象及凝聚态研究进行了展望,为二维大分子及材料的发展提供了新思路.     

二羟基二(原碘酸根)合镍(Ⅳ)配离子氧化乙醇的反应动力学及机理

在碱性介质中用分光光度法研究了二羟基二(原碘酸根)合镍(Ⅳ)配离子(DDN)于25～40℃区间氧化乙醇的反应动力学。结果表明,反应对DDN为一级,对乙醇为正分数级。准一级速率常数k_obs随[OH^-]增加而增大,随[IO₄^-]增加而减小。有微弱的负盐效应。在氮气保护下,反应不能引发丙烯酰胺的聚合。提出一个包括Ni(Ⅳ)和乙醇生成加合物前期平衡的反应机理,导出的速率方程满意地解释了所有的实验结果,并计算出平衡常数、速控步骤的速率常数及相应的活化参数。     

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.