微波促进的杂环化合物合成研究

对微波技术在有机杂环化合物合成研究中的应用做了概述：1)四员杂环;2)五员杂环;3)六员杂环;4)七员杂环;5)大杂环。     

Synthetic Routes to Coumarin(Benzopyrone)-Fused Five-Membered Aromatic Heterocycles Built on the α-Pyrone Moiety. Part II: Five-Membered Aromatic Rings with Multi Heteroatoms

Coumarins are natural heterocycles that widely contribute to the design of various biologically active compounds. Fusing different aromatic heterocycles with coumarin at its 3,4-position is one of the interesting approaches to generating novel molecules with various biological activities. During our continuing interest in assembling information about fused five-membered aromatic heterocycles, and after having presented mono-hetero-atomic five-membered aromatic heterocycles in Part I. The current review Part II is intended to present an overview of the different synthetic routes to coumarin (benzopyrone)-fused five-membered aromatic heterocycles with multi-heteroatoms built on the pyrone ring, covering the literature from 1945 to 2021.     

Ozonolysis of five-membered heterocycles

The relative reaction rate of five-membered heterocycles with ozone was evaluated. These relative rates were correlated to the highest bond order value in the corresponding ring, calculated by the convenient HMO method. From this correlation, the reactivity of heterocycles with ozone was able to be predicted. Also it was concluded that the predominant product in the ozonolysis of five-membered heterocycles containing an oxygen atom was the corresponding carboxylic acid, while nitrogen heterocycles gave the corresponding amide.     

Synthesis of Pyrimidine-Annelated Heterocycles: Regioselective Heterocyclization of 5-(Cyclohex-2-enyl)-1,3-dimethyl-6-hydroxyuracil [1]

 5-(Cyclohex-2-enyl)-1,3-dimethyl-6-hydroxyuracil undergoes regioselective heterocyclization to afford fused tricyclic heterocycles upon treatment with bromine and m-CPBA. However, the same substrate furnished bridged tricyclic heterocycles when treated with N-iodosuccinimide and conc. H₂SO₄ and a mixture of bridged tricyclic heterocycles and fused tricyclic heterocycles when treated with hexamine hydrotribromide or pyridine hydrotribromide.     

Synthetic routes to seven and higher membered S-heterocycles by use of metal and nonmetal catalyzed reactions

Nitrogen, oxygen, and sulfur containing heterocycles have a wide range of biological activities. Metal and nonmetal catalysts are used in organic reactions with high activity. New strategies have been developed for the preparation of heterocycles in the last decades. The metal and nonmetal catalyzed synthesis of heterocycles is becoming an important and highly rewarding protocol in organic synthesis. In this review article, the synthesis of seven and higher-membered S-heterocycles is presented with the application of metal and nonmetal catalysts for the period from 1968 to 2018.     

Tandem arylation-reduction of acyl heterocycles. Convenient synthesis of benzyl heterocycles

Tandem arylation-reduction of a series of acyl heterocycles using phenyl-, 4-methylphenyl-, and 4-methoxy-phenyllithium reagents followed by lithium-ammonia-ammonium chloride reduction afforded the corresponding benzyl heterocycles. The acyl heterocycles surveyed in this study contained furan, 2,3-dihydro-4H-1-benzopyran, 4H-1-benzopyran, thiophene, 4,5,6,7-tetrahydrobenzo[b]thiophene, 2,3-dihydro-4H-1-benzothiopyran, and pyridine nuclei. All acyl heterocycles yielded the corresponding benzyl heterocycles except 2,3-dihydro-4H-1-benzothiopyran-4-one, which selectively cleaved during reduction to give the corresponding 2-(1-arylpropyl)benzenethiols.     

氮杂Wittig反应的最近进展

综述了最近几年氮杂Wittig反应的研究进展,包括分子间氮杂Wittig反应、分子内氮杂wittig反应及串联的氮杂Wittig反应。讨论了氮杂Wittig反应在一些含氮杂环、稠杂环及天然产物合成中的应用。     

Construction of Nine‐Membered Heterocycles through Palladium‐Catalyzed Formal [5+4] Cycloaddition

The first catalytic formal [5+4] cycloaddition to prepare nine‐membered heterocycles is presented. Under palladium catalysis, the reaction of N‐tosyl azadienes and substituted vinylethylene carbonates (VECs) proceeds smoothly to produce benzofuran‐fused heterocycles in uniformly high efficiency. Highly diastereoselective functionalization of the nine‐membered heterocycles through peripheral attack is also demonstrated.     

用环加成反应合成含氟杂环化合物的研究

综述了近年来利用一些新型的含氟砌块，通过它们的环加成反应来高效地合成 含氟杂环化合物的研究，其中包括以下两个部分：(1)用1，3—偶极环加成反应合 成五元含氟杂环化合物；(2)用杂原于Diels-Alder反应合成六元含氟杂环化合物．     

Selenium heterocycles XIV. 2,6-diaryltetrahydroselenopyran-4-ones

In our previous communications, we have reported that selenium heterocycles could be easily obtained either by using selenium dioxide (3) or by selenium (4). In continuation of our studies on the synthesis and chemistry of selenium heterocycles, it was of interest to use aluminum selenide as the precursor of selenium in the preparation of selenium heterocycles.     

Ag-mediated synthesis of six-membered N-heterocycles

Abstract

One of the highly emerging and an important aspect of organic chemistry is the metal catalyzed synthesis of heterocycles. The methods used earlier for the synthesis of heterocycles were significant in the organic synthesis and developing cost-effective, improved and facial methods were beneficial to construct the complex architectures. For the both stereoselective and regioselective synthesis of six-membered nitrogen containing heterocycles, cyclic reactions that are Ag-mediated have known to be very efficient. The present review covers the applications of Ag in the formation of six-membered nitrogen containing heterocycles.     

Photochemical mediated reactions in five-membered O-heterocycles synthesis

Photochemical mediated synthesis in organic chemistry is a highly expanding area. This is a widely exploited area of research for the construction of new pharmaceutically significant heterocycles. Recently many reports appeared for the synthesis of heterocycles photochemically due to a wide range of biological activities associated with them. In this article, I have described the synthesis of a number of oxygen-bearing five-membered heterocycles.     

Synthesis of Pyrimidine-Annelated Heterocycles: Regioselective Heterocyclization of 5-(Cyclohex-2-enyl)-1,3-dimethyl-6-hydroxyuracil [1]

Summary.  5-(Cyclohex-2-enyl)-1,3-dimethyl-6-hydroxyuracil undergoes regioselective heterocyclization to afford fused tricyclic heterocycles upon treatment with bromine and m-CPBA. However, the same substrate furnished bridged tricyclic heterocycles when treated with N-iodosuccinimide and conc. H₂SO₄ and a mixture of bridged tricyclic heterocycles and fused tricyclic heterocycles when treated with hexamine hydrotribromide or pyridine hydrotribromide. Corresponding author. E-mail: kcm@klyuniv.ernet.in Received September 27, 2001. Accepted (revised) December 3, 2001     

Sodium Phosphaethynolate as a Building Block for Heterocycles

Phosphorus‐containing heterocycles have evolved from laboratory curiosities to functional components, such as ligands in catalytically active metal complexes or molecular constituents in electronic devices. The straightforward synthesis of functionalized heterocycles on a larger scale remains a challenge. Herein, we report the use of the phosphaethynolate (OCP)^? anion as a building block for various sterically unprotected and functionalized hydroxy substituted phosphorus heterocycles. Because the resulting heterocycles are themselves anions, they are building blocks in their own right and allow further facile functionalization. This property may be of interest in coordination chemistry and material science.     

Applications of palladium dibenzylideneacetone as catalyst in the synthesis of five-membered N-heterocycles

A wide variety of biological activities are possessed by N, O, and S containing heterocycles and recently many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal became highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of nitrogen containing five-membered heterocylces in the presence of palladium dibenzylideneacetone as a catalyst.     

Metal catalysts: applications in higher-membered <Emphasis Type="Italic">N</Emphasis>-heterocycles synthesis

In recent decades, a large number of reports related to synthesis of N-, O- and S-containing heterocycles have appeared owing to a wide variety of their biological activity. The metal-catalyzed synthesis of heterocycles is becoming an important and highly rewarding protocol in organic synthesis. This review focuses on the use of metal as a catalyst for the synthesis of nitrogen-containing heterocycles. It describes the formation of higher-membered heterocyclic rings.     

Multisubstituted N-fused heterocycles via transition metal-catalyzed cycloisomerization protocols

Two complementary protocols for assembly of multisubstituted N-fused heterocycles have been developed. It was demonstrated that 1,3-disubstituted N-fused heterocycles, including indolizines, pyrroloquinoxalines, and pyrrolothiazoles can easily be synthesized via an exceptionally mild and efficient method involving a novel silver-catalyzed cycloizomerization of propargyl-containing heterocycles. Alternatively, 1,2-disubstituted heterocycles can be accessed through the novel cascade transformation involving an alkyne-vinylidene isomerization with concomitant 1,2-shift of hydrogen, silyl, stannyl, or germyl groups. This mild and simple method allows for selective and highly efficient synthesis of indolizines, pyrroloisoquinolines, pyrroloquinoxalines, pyrrolopyrazines, and pyrrolothiazoles.     

Copper catalyzed synthesis of seven and higher membered heterocycles

Nitrogen, oxygen, and sulfur-containing heterocycles have a wide range of biological activities. Metal catalysts are used in organic reactions with high activity. New methods have been explored for the synthesis of heterocyclic compounds in the past few years. The preparation of heterocycles with the assistance of metal catalyst is becoming a highly rewarding strategy in organic synthesis. In this review article, the synthesis of seven and higher-membered heterocycles is presented using copper as a catalyst.     

Janus-AT bases: synthesis, self-assembly, and solid state structures

The high yielding synthesis of heterocycles with defined H-bond accepting and donating capabilities provides for the design of self-assembling structures and specific recognition of biological targets. Herein we report the syntheses and solid-state structures of three self-complementary uracil/thymine derivatives where each presents the standard ADA face inherently complementary to adenine and a synthetically appended DAD face complementary to uracil/thymine. These heterocycles, which have never before been reported or characterized, represent diaminopurine-uracil/thymine hybrids that, in two of the three cases, relate to previously reported heterocyclic hybrids of G and C. All three heterocycles crystallized to afford the first X-ray crystal structures of self-complementary heterocycles capable of ADA-DAD pairing. The potential use in DNA and RNA recognition are briefly discussed.     

Multiple nitrogen-containing heterocycles: Metal and non-metal assisted synthesis

A wide variety of biological activities are possessed by N-, O-, and S-containing heterocycles and recently many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and nonmetal became highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of multiple-nitrogen containing five-membered heterocylces in the presence of metal and nonmetal. It describes the formation of five-, six-, and seven-membered heterocyclic rings.