On triazoles XXXI. The reaction of 1,2,4-triazolylcarbothiohydrazides with homo- and heterocyclic ketones. An unexpected reaction leading to 4,5-polyalkylene thiazoles

The reaction of 1,2,4-triazolylcarbothiohydrazides with homo- and heterocyclic ketones to yield 8-spiro-[1,2,4]triazolo[1,5-d][1,2,4,6]tetrazepine-5-thiones 7 (n = 4, 5, 6, 7 and 11), 8 and 9 , respectively, all representing novel ring systems was studied. Providing the reaction at higher temperature a novel reaction was observed to yield 4,5-polyalkylene thiazoles for which a mechanism is proposed.     

Unexpected multicomponent reaction of 2/4-methoxyarylaldehydes with arylhydroxylamines and maleic anhydride: a novel synthesis of unsymmetrical diarylamines

Unsymmetrical diarylamines have been synthesized by a novel, unexpected multicomponent reaction between methoxyarylaldehydes, N-arylhydroxylamine and maleic anhydride. A possible mechanism for the formation of the product is proposed. The reaction was also carried out under microwave irradiation.     

Novel Synthetic Approach Toward C‐Substituted Piperazine Derivatives via C‐N Bonds Formation of α‐Bromoarylethanones and Ethanolamine

A new method for the synthesis of novel C‐substituted piperazine derivatives bearing aryl substituents on 2,6‐C positions has been developed by one‐pot three‐component sequential reaction of α‐bromoarylethanones with ethanolamine in the presence of formic acid. The structure of the novel compounds was established by nuclear magnetic resonance (NMR), mass spectrometry (MS), and elemental analysis. In addition, the crystal structure of 4e was determined by single X‐ray crystallography and a possible reaction mechanism was proposed.     

Indium-mediated reaction of nitroethane and aldehydes: characterization of the nucleophilic organoindium species

A novel method for the preparation of 2-nitroalkan-1-ols by an indium-promoted reaction of bromonitromethane and 2-bromonitropropane with a variety of aldehydes was recently reported. Extension of the procedure to 1-bromo-1-nitroethane, which gives rise to a new chiral centre, was considered. On the basis of the diastereoselectivity of the nitroalkanols formed and NMR studies on the reaction mixtures, a mechanistic proposal for the indium-promoted reaction of bromonitroalkanes and aldehydes is discussed. The proposed mechanism allows the prediction of the stereochemical outcome of the present reaction.     

一个新的制备咪唑并[1，5－α]吡啶衍生物的串联反应

发现5－咪唑甲醛（1）与γ－溴代巴豆酸酯（2）在弱碱条件下首先进行亲核 取代反应生成3，继而生成γ－碳负离子并转移到α－位，然后进行了分子内亲核 进攻成环，脱水生成4的串联反应，提供了一个合成咪唑并[1，5－α]吡啶－7－羧 酸酯衍生物的新方法。     

苯乙烯吡啶类化合物合成的新方法

对Heck反应在苯乙烯吡啶类化合物合成中的应用进行了较为深入的研究,并提出了反应机理.采用改进的钯催化反应以高产率合成了一系列苯乙烯吡啶类化合物,为苯乙烯吡啶类化合物的制备提供了一种方便有效的新方法     

含有联萘环结构的新型环氧树脂的合成与性能研究

以2-萘酚为原料,先合成出2,2?二羟基-1,1?联萘,再合成出一种新型的具有联萘结构的环氧树脂(BEBN)。通过红外光谱研究了树脂的结构,推测了树脂合成的机理,并对树脂的性能作了一定的研究。该树脂的固化物表现出良好的热性能及力学性能。     

Trifluoroacetic acid catalyzed dibenzodiazocine synthesis: optimization and mechanism study

Dibenzo[b,f][1,5]diazocines, a class of potential building blocks for novel electrochemical actuators, were synthesized via a novel, efficient acid-catalyzed reaction of 2-acylbenzoisocyanate at room temperature. Real-time NMR analysis and the captured intermediate showed the mechanism was an unprecedented cyclization of the isocyanate with the neighboring acyl group, followed by the dimerization.     

Divergent intramolecular reactions between phosphines and alkynes

A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was developed.This provided a novel and simple access to a large variety of(Z)-alkenylphosphine oxides and phospholane oxides.Our preliminary studies suggested that these divergent reactions are closely related to the reaction condition and molecular structure.A possible mechanism of C-P bond cleavage of a pentacoordinated hydroxyphosphorane intermediate was proposed.     

Formation of novel thiazolomorphinans and thiazoloaporphines

A novel strategy has been developed for the synthesis of ring A fused thiazolomorphinans and ring D fused thiazoloaporphines offering the possibility of formation of regioisomeric products. The conventional thermal thiazole-forming reaction was replaced with microwave initiation and a detailed discussion has been presented on the proposed mechanism of the ring closure.     

Metal-free carbon-nitrogen bond-forming coupling reaction between arylboronic acids and organic azides

A novel and efficient metal-free carbon-nitrogen bond-forming coupling reaction between arylboronic acids and organic azides is reported. The reaction is fairly general for the preparation of secondary aromatic amines. Furthermore, the reaction is very functional-group tolerant. A possible mechanism is also proposed.     

异维A酸新木脂素酯的合成与表征

以香草醛(或对羟基苯甲醛)和丙二酸为原料,经Knoevenagel反应、酯化、氧化银为氧化剂的自由基仿生氧化偶联反应合成了新木脂素3a,3b。3a,3b分别与异维A酸酯化,合成了两种新型的异维A酸新木脂素酯4a和4b。用1H NMR,IR和MS对它们的结构进行了表征。研究了异维A酸酯的反应机理。     

A facile oxidation and oxygen insertion of the cyclopentadiene ring by molecular oxygen in solution

[reaction: see text] Oxidation of substituted cyclopentadienes by molecular oxygen afforded the corresponding pyrylium cations in acidic solution, whereby an oxygen atom was inserted into the cyclopentadiene ring. This novel one-step reaction proceeds in a different yield depending on substitution patterns of the cyclopentadiene. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed.     

Stanna-Brook rearrangement of carboxylic acid derivatives. Synthetic utility and mechanistic studies

[reaction: see text] The reaction of R(3)SnLi with carboxylic acid derivatives proceeds through a novel, very fast stanna-Brook rearrangement that generates alpha-alkoxyorganolithium compounds as intermediates. The outcome of these reactions depends on the nature of the carboxyl derivatives. Reaction of R(3)SnLi with ester derivatives gives rise to coupled products through a novel C-C bond formation reaction. Experimental evidence of the detailed reaction mechanism is provided.     

Syntheses of salvilenone and related compounds: II. A novel rearrangement of a tetrahydrophenalenone to a naphthopyranone

The reaction of isopropenyl carbinol ( 2 ) with aqueous hydrobromic acid and hydroiodie acid gave salvilenone ( 1 ) and naphthopyranone ( 3 ) respectively. The reaction mechanism has been investigated. The formation of ( 3 ) was undergone a novel rearrangement of a tetrahydrophenalenone to a naphthopyranone.     

龙葵醛的新合成方法研究

龙葵醛是一种珍贵的香料 ,也是重要的化工原料 ,广泛应用于香料、医药、染料及农药等行业 .龙葵醛的工业生产以苯乙酮和一氯醋酸乙酯为原料 ,按 Darzens法合成[1,2 ] .苯乙酮与一氯醋酸乙酯在强碱作用下制得甲基苯基环氧丙酸酯 ,该酯经皂化、中和、水解成酸 ,再将该酸加热分解 ,得龙葵醛 .该方法操作比较复杂 ,产率和产品纯度也不高 .为了寻找产率高、纯度好且成本低的新制备方法已有广泛的研究 .Rivero等 [3]提出的 2 -甲基苯乙醇氧化法 ,尽管产率较高 ,但反应温度要在 -78℃ ,不利于工业化生产 .陈万之等[4 ] 利用各种铑螯合物作为催化剂…     

微波辅助下铑催化二芳基膦酰胺与炔烃的C—H活化/环化反应

研究了微波条件下[RhCp ^*Cl₂]₂(Cp ^*: 五甲基环戊二烯基)催化二芳基膦酰胺与炔烃的C—H活化/环化反应, 以中等到较好的收率获得了一系列具有环状结构的含氟膦酰胺衍生物. 通过考察溶剂、 温度、 时间以及碱等因素, 筛选了最佳反应条件. 对该催化体系进行放大量实验, 也获得了良好的结果. 在实验基础上, 推测了可能的反应机理, 并将此方法应用于一种新型含氟代环状膦酰胺二胺单体的制备.     

C-F bond activation by modified sulfinatodehalogenation: facile synthesis and properties of novel tetrafluorobenzoporphyrins by direct intramolecular cyclization and reductive defluorinative aromatization of readily available beta-perfluoroalkylated porphyrins

A facile and efficient synthesis of various novel fluorinated extended porphyrins has been developed. The method is based on the direct intramolecular cyclization and reductive defluorinative aromatization of readily available beta-perfluoroalkylated porphyrins by highly selective C-F bond activation under modified sulfinatodehalogenation reaction conditions. Various beta-(omega-chloroperfluoroalkyl)-meso-tetraphenylporphyrins prepared readily by sulfinatodehalogenation reaction or palladium-catalyzed cross-coupling reaction were treated with Na2S2O4/K2CO3 (10:10 equiv per RF tail) in DMSO at 100 degrees C for 10-30 min, resulting in good yields of novel beta-tetrafluorobenzo-meso-tetraphenylporphyrins. That further reduction of C-F bonds of the products was not observed under the optimal conditions indicates the high selectivity of the reaction. It was found that the amount of sodium dithionite, base, and central metal ion of substrate porphyrins play important roles in the reaction. Detailed mechanism investigations and systematic studies on X-ray crystallographic structure and photophysical and electrochemical properties of a series of new tetrafluorobenzoporphyrins are also reported.     

Design and Synthesis of Novel Fluorine-containing Acrylates

It has been known that introduction of fluorine atom in molecule may lead to significant influence on the biological and physical properties of compounds due to increase of membrane permeability,hydrophobic binding,stability against metabolic oxidation,etc1.Since fluorine is virtually absent in the living tissue,fluorine-containing compounds are expected to serve as important and useful bioactive compounds for medicinal chemistry and chemical biology2.Therefore the development of synthetic met…     

A novel rearrangement of eudesmanolide enol ester epoxide: facile 1-step construction of the salvialane sesquiterpene skeleton

A novel carbon–carbon rearrangement for the eudesmanolide sesquiterpene enol ester epoxide in the presence of a catalytic amount of Lewis acids (3–10 mol%) or an excess of NaOMe is disclosed. This reaction was developed to give a facile, one-step procedure for the construction of naturally occurring and bioactive salvialane sesquiterpenes. The reaction conditions were investigated extensively and a possible reaction mechanism is also discussed.