Microwave-Assisted Synthesis of Five-Membered O-Heterocycles

The development of new strategies for synthesis of five-membered O-heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in oxygen-containing five-membered heterocyclic compound synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of five-membered O-heterocycles.     

Microwave-Assisted Synthesis of Five-Membered O,N-Heterocycles

The development of new strategies for the synthesis of five-membered O,N-heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in oxygen- and nitrogen-containing five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of five-membered O,N-heterocycles.     

Microwave-Assisted Synthesis of Five-Membered O,N,N-Heterocycles

The development of new strategies for synthesis of five-membered O,N,N-heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in oxygen and two nitrogen atoms containing five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of five-membered O,N,N-heterocycles.     

Synthesis of Fused Five-Membered N,N-Heterocycles Using Microwave Irradiation

The development of new strategies for the synthesis of fused heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in the synthesis of fused five-membered heterocyclic compounds containing two nitrogen atoms is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of fused five-membered N,N-heterocycles.     

Insight into Microwave-Assisted Synthesis of Benzo Derivatives of Five-Membered N,N-Heterocycles

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in nitrogen-containing benzo derivatives of five-membered heterocyclic compounds synthesis is presented here, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of benzo derivatives of five-membered N,N-heterocycles.     

Recent Impact of Microwave-Assisted Synthesis on Benzo Derivatives of Five-Membered N-Heterocycles

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in nitrogen-containing benzo derivatives of five-membered heterocyclic compounds synthesis is presented here, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of benzo derivatives of five-membered N-heterocycles.     

Metal and organo-complex promoted synthesis of fused five-membered O-heterocycles

Abstract

One of the highly emerging and an important aspect of organic chemistry is the metal and organo-complex promoted synthesis of the heterocycles. The methodologies used earlier for its synthesis were less approachable to the organic chemist due to their high cost, highly sophisticated instrumentation and problematic methods. For both stereoselective and regioselective synthesis of fused five-membered O-containing heterocycles, cyclic reactions that are metal and organo-complex promoted have been known to be very efficient. The present review article covers the different applications of metals and organo-complexes in the formation of fused five-membered oxygen containing fused heterocycles. The fascinating research that has been done in this area is enclosed in this review.     

Microwave-Assisted Synthesis: Fused Five-Membered N-Heterocycles

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in nitrogen-containing fused five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of fused N-heterocycles.     

Advances in Microwave-Assisted Synthesis for Five-Membered N-Heterocycle Synthesis

The development of new strategies for the synthesis of small-sized heterocycles hasremained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in the synthesis of nitrogen-containing five-membered heterocyclic compounds is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of N-heterocycles.     

Microwave-assisted synthesis of five-membered S-heterocycles

The development of new strategies for synthesis of five-membered S-heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in sulfur-containing five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the last 5–10 years. This contribution covers the literature concerning the total synthesis of five-membered S-heterocycles under microwave and combined effect of microwave and solid-phase.     

Role of Microwaves in the Synthesis of Fused Five-Membered Heterocycles with Three N-Heteroatoms

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in three nitrogen atoms containing fused five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of N,N,N-heterocycles. The literature data are summarized based on the type of cycles.     

Synthesis of Five-Membered N,N,N- and N,N,N,N-Heterocyclic Compounds: Applications of Microwaves

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation to the synthesis of five-membered heterocyclic compounds containing three and four nitrogen atoms is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of N,N,N- and N,N,N,N-heterocycles. The literature data are summarized based on the size and type of cycles.     

Total Synthesis of Aculenes B and D

The first total synthesis of aculene D, a structurally rare nordaucane-type natural product exhibiting quorum sensing inhibitory activity, has been accomplished from a known five-membered hydroxy carboxylic acid. Nucleophilic addition of methallylzinc bromide to a β-keto aldehyde intermediate under Barbier conditions to install the secondary hydroxy group on the seven-membered ring of aculene D gave the corresponding alcohol with an undesired configuration predominantly. On the other hand, the protection of its keto group as the ethylene acetal induced a reversal of diastereoselectivity, affording a desired diastereomer in a selective manner. The construction of the seven-membered ring was realized by ring-closing metathesis using a triethylsilyl-protected monocyclic diene ester precursor. An additional five-step manipulation on the cyclization product including the installation of an ethyl group on the five-membered ring completed the synthesis of aculene D, whose esterification with an N-protected l -proline followed by deprotection also achieved the first total synthesis of aculene B.     

Phase transfer catalysis in the chemistry of five-membered nitrogen-containing heterocycles

The methods for synthesis and reactions of five-membered nitrogen-containing heterocycles under the conditions of phase transfer catalysis as well as the application of quaternized heterocycles as phase transfer catalysts are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2115–2121, November, 1995.     

焦脱镁叶绿酸的Knoevenagel反应及其杂环取代衍生物的合成

以焦脱镁叶绿酸-d甲酯(MPPd)为起始原料, 通过其醛基与连有五元杂环的β-二酮、α-氰基酮和丙二腈的活性亚甲基进行Knoevenagel反应, 完成3-位五元杂环取代的焦脱镁叶绿酸-a甲酯衍生物. 所合成的新化合物均经UV, IR, ¹H NMR及元素分析证明其结构.     

Recent developments in the synthesis of nitrogen containing five-membered polyheterocycles using rhodium catalysts

The nitrogen-, oxygen- and sulfur-heterocycles possess a number of pharmacological activities and recently many reports appeared for the synthesis of these heterocycles. In few past years, metals are applied for the production of these heterocycles. These synthetic strategies involving metal catalysts became highly significant in the synthetic organic chemistry. This review article features the applications of rhodium metal catalysts for the preparation of five-membered N-polyheterocylces.     

Synthesis of 2t-Substituted-1r,3c-BIS(2′-Hydroxy-5-Substituted-Benzyl)-Imidazolidines by Reaction of 1,3-BIS(2′-Hydroxy-5′-Substituted-Benzyl)-Imidazolidines with Aromatic Aldehydes

A one-step synthesis of 2t-substituted-1r,3c-bis(2′-hydroxy-5′- substituted-benzyl)-imidazolidines from 1,3-bis(2′-hydroxy-5′-substituted-benzyl)-imidazolidines and aromatic aldehydes is reported. The relative stereochemistry of the five-membered ring was evident from ¹H NMR measurements combined with MMX calculations.     

Photochemical reactions as key steps in five-membered N-heterocycle synthesis

The chemists have been interested in light as an energy source to induce chemical reactions since the beginning of scientific chemistry. This review summarizes the chemistry of photochemical reactions with emphasis of their synthetic applications. The organic photochemical reactions avoid the polluting or toxic reagents and therefore offer perspectives for sustainable processes and green chemistry. In summary, this review article describes the synthesis of a number of five-membered N-heterocycles.     

Photoreaktionen des 3-Methyl-4-phenylsydnons

Photoreactions of 3-Methyl-4-phenylsydnone A procedure for the synthesis of 3-methyl-4-phenylsydnone (1) is given. UV. irradiation of 1 in solution generates the nitrile-imine 4 which reacts with activated C, C double bonds and with heterocumulenes to give five-membered heterocycles. In contrast to the 2H-azirines which photochemically react with the C, O double bond of phenylisocyanate, 4 adds to the C, N double bond of the latter.