2-芳基-3,4-二氮杂芴酮和2-芳基-3,4-二氮杂螺二芴衍生物的合成

水合茚三酮与芳甲基酮、水合肼缩合环化制得2-芳基-3,4-二氮杂芴酮(2); 2经还原得2-芳基-3,4-二氮杂芴(3).2与2-溴联苯格氏试剂反应得到中间体叔醇(4); 4在酸性条件下关环合成了2-芳基-3,4-二氮杂螺二芴,其结构经1H NMR,13C NMR和元素分析表征.     

反式2,3-二芳基取代-1-氨基环丙烷羧酸的合成及其结构研究

芳香醛与马尿酸在Erlenmeyer反应条件下缩合得到(Z)-2-苯基4芳亚甲基-5(4H)-噁唑酮，然后在室温下与芳基重氮甲烷通过非对映高立体选择性1，3-偶极环加成反应得到螺环化合物，再经醇解开环、水解去保护合成出反式2，3-二芳基-1-氨基取代环丙烷羧酸．通过元素分析，IR，^1H NMR，^13C NMR，MS和X射线晶体测定，确认了它们的化学结构和立体构型．实验结果表明，通过选择适当的芳香醛和芳基重氮甲烷，可以得到不同立体构型的反式2，3-二芳基取代-1-氨基环丙烷羧酸．     

低价钛引起的(3-氧代-1,3-二芳基)丙基丙二腈的还原环化反应

报道了低价钛试剂(TiCl-Zn体系)与(3-氧代-1,3-二芳基)丙基丙二腈的反应.研究发现,低价钛可引起(3-氧代-1,3-二芳基)丙基丙二腈的成环反应,生成2-氰基-3,5-二芳基-1-氨基环戊烯、反式和顺式2-氨基-3-氰基-1,4-二芳基-2-环戊烯-1-醇3种产物,并用X射线衍射法确定了后两种异构体的构型.     

2,5-二甲基-3,4-二乙酰基-1-芳基吡咯的合成

多取代吡咯;二乙酰基己二酮;取代苯胺;2;5-二甲基-3;4-二乙酰基-1-芳基吡咯的合成     

2’-芳基-3-（1，4，5，6-四氢-6-哒嗪酮-3-羰基）氨基硫脲及其环化产物的合成

以α-酮戊二酸为起始原料，合成了1，4，5，6-四氢．6-哒嗪酮-3-甲酰肼(2)，然后将2与异硫氰酸芳基酯反应得到相应的芳基氨基硫脲衍生物3a～3f．用硫酸、醋酸汞或氢氧化钠分别将芳基氨基硫脲环化得到一系列新的1，3，4-噻二唑、1，3，4-噁二唑和1，2，4-三唑的衍生物．化合物的结构经元素分析，IR，^1HNMR和MS谱得以证实．     

N,N′-二芳基己二酰双偶氮化合物的合成及其结构表征

N;N′-二芳基己二酰二肼;N;N′-二芳基己二酰双偶氮化合物;合成     

N,N′-二芳基硫代草酰胺与1,2-二溴乙烷的反应的研究

以N,N′-二芳基二硫代草酰胺与1,2-二溴乙烷进行S烷基化反应,合成了一系列2,3-双芳基亚氨基-1,4-二硫杂环己烷,反应在4 h内完成,产率52%～62%.产物结构经元素分析,IR,1H NMR及MS表征,并以单晶X射线衍射分析进一步确证.     

1,4-二氢-4-芳基-3,5-吡啶二羧酸酯的合成及表征

基于二氢吡啶化合物的构效关系, 设计了一系列1,4-二氢-4-芳基-3,5-吡啶二羧酸酯新化合物. 含有易于水解基团的1,4-二氢-4-芳基-3,5-吡啶二羧酸酯类化合物在碱性条件下水解合成了重要中间体1,4-二氢-4-芳基-3,5-吡啶二羧酸单酯, 收率93%～99.8%. 该二羧酸单酯与α-溴代芳基乙酮在相转移剂催化下反应合成目标化合物, 收率74%～99%. 中间体和目标化合物经¹H NMR, ¹³C NMR, IR, MS和元素分析等确证.     

醋酸溶液中2,3-二芳基-喹喔啉的简便合成

1,2-二芳基乙二酮与1,2-苯二胺在室温醋酸溶液中反应数分钟,生成2,3-二芳基一喹喔啉.反应时间短(1～10min),产率高(90%～97%),反应条件温和,操作简便.     

N，N’-二芳基硫代草酰胺与1，2-二溴乙烷的反应的研究

以N,N'-二芳基二硫代草酰胺与1,2-二溴乙烷进行S烷基化反应,合成了一系列2,3-双芳基亚氨基-1,4-二硫杂环己烷,反应在4h内完成,产率52%～62%.产物结构经元素分析,IR,1HNMR及MS表征,并以单晶X射线衍射分析进一步确证.     

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.