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.     

Syntheses of the isomeric benzoquinazolines: A review

The synthesis of derivatives of benzo[f]quinazoline, benzo[g]quinazoline and benzo[h]quinazoline is reviewed. Each class of compound is treated separately. The review covers ring formations as well as group modifications.     

金催化的炔烃羟基化反应: 合成2取代苯并呋喃化合物

本文报道了一种以邻炔基苯酚为原料,通过金催化的炔烃羟基化反应合成2取代苯并呋喃的方法. 该方法可以在温和的条件下快速以高产率得到各种2取代苯并呋喃. 关键前体邻炔基苯酚可以很容易由Sonogashira 反应制备.     

Synthesis of novel scaffolds based on thiazole or triazolothiadiazine linked to benzofuran or benzo[d]thiazole moieties as new hybrid molecules

Abstract

A synthesis of novel hybrid molecules containing thiazole or bis(thiazoles) each bearing benzofuran and/or benzo[d]thiazole moieties by the reaction of the appropriate thioamide derivatives with the corresponding bis-bromoacetyl derivatives is reported. Mono- and bis(triazolothiadiazine) derivatives based on benzofuran or benzo[d]thiazole moieties were also synthesized in good yields by the reaction of the appropriate bis(bromoacetyl) derivatives with each of 4-amino-5-mercapto-1,2,4-triazoles and their corresponding bis-derivatives.     

Sequential Two-Fold Claisen Rearrangement,One-Pot Ring-Closing Metathesis and Cross-Metathesis as a Route to Substituted Benzo[b]azepine-2-one,Benzo[b]azepine and Benzo[b]oxepine Derivatives

A synthetic protocol involving sequential use of three atom-economic processes viz. Claisen rearrangement, ring-closing metathesis and cross metathesis has been developed to access 7-substituted benzo[b]azepine and benzo[b]oxepine derivatives starting from appropriate aniline or phenol in good overall yield. A one-pot RCM-CM protocol has also been developed for the synthesis of benzazepine and benzoxepine derivatives.     

Pd‐catalyzed C‐H Arylation: A General Route for the Synthesis of Benzo[b]carbazolenaphthoquinones

A short, efficient and general methodology for benzo[b ]carbazolenaphthoquinones was developed via Pd‐catalyzed C‐H arylation process. This methodology was successfully applied to the synthesis of highly biologically active compound 5H–benzo[b ]carbazole‐6,11‐diones. Additionally, one‐pot synthesis of benzo[b ]phenazine‐6,11(5H,12H)‐dione derivatives was also explored in aqueous medium.     

Efficient One‐pot Synthesis,Antimicrobial and Docking Studies of Some Newer Tetrahydro‐4H‐benzo [1,3‐e]oxazines and Related β‐Acylamino Ketone Derivatives

A concise one‐step procedure was developed for the synthesis of some newer tetrahydro‐4H‐benzo[1,3‐e ]oxazines and β‐acylamino ketone derivatives via condensation of cyclohexanone derivative with different aromatic aldehydes and nitriles in the presence of tetrachlorosilane/zinc chloride (TCS/ZnCl₂) reagent mixture under ambient conditions. Docking studies for the synthesized benzo‐oxazine derivatives were designed and a model of highly active derivatives was mapped for the antimicrobial screening.     

Preparation of 3‐aminoalkylbenzo[b]thiophenes

We report an efficient entry into substituted 3‐(ω‐aminoalkyl)‐benzo[b]thiophenes that allows rapid generation of structural diversity. Alkylation of α,ω‐dihaloketones with thiophenols followed by acid‐catalysed cyclisation led to an efficient synthesis of 3‐(ω‐aminoalkyl)benzo[b]thiophenes. 2‐Carboethoxy derivatives were prepared using a directed ortho‐metallation approach. These derivatives were readily converted into the corresponding amines.     

The synthesis of the monomethyl derivatives of benzo[b]naphtho[2,3-d]thiophene

The synthesis of all the monomethyl derivatives of benzo[b]naphtho[2,3-d]thiophene is described.     

Cyclopentadienes Annelated with Five-membered Heterocycles: Methods of Synthesis, Heteroorganic Derivatives, and Synthetic Precursors. (Review)

The review is devoted to cyclopentadienes annelated with five-membered heterocycles (furan, pyrrole, thiophene, and their benzo analogs) (hetarenocyclopentadienes), their heteroorganic derivatives, and the synthetic precursors (hetarenocyclopentanones).     

Palladium‐Catalyzed Domino CH/NH Functionalization: An Efficient Approach to Nitrogen‐Bridged Heteroacenes

Palladium‐catalyzed domino C?H/N?H functionalization for the synthesis of novel nitrogen‐bridged thienoacenes and 10H‐benzo[4,5]thieno[3,2‐b]indole derivatives from dihaloarene is reported. This domino sequence consists of initial C?H functionalization of the benzo[b]thiophene moiety, followed by Buchwald–Hartwig coupling. This transformation is also useful for the synthesis of highly π‐extended compounds.     

Effect of the heteroatom of a benzo[b]-annelated five-membered heteroring on the structure and properties of an aminovinyl ketone fragment included in the ring

An analysis of the results of theoretical and physicochemical studies of and x-ray diffraction data for a series of aminovinyl ketones — derivatives of hydroxy aldehydes of benzo[b]-annelated five-membered heterosystems — is presented. In addition to the peculiarities of the aminovinyl ketone fragment, the effect of the heteroatom of the five-membered ring on the structure and properties of aminovinyl ketones, which consists in direct electronic conjugation of the ring carbonyl group with the heteroatom, was ascertained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 878–882, July, 1986.     

Synthesis of new 5‐substitutedbenzo[b]thiophene derivatives

Previous works of our group have dealt with the synthesis of 1‐(aryl)‐3‐[4‐(aryl)piperazin‐1‐yl]propane derivatives in the search for new and efficient antidepressants with a dual mode of action: serotonin reuptake inhibition and 5‐HT_1A receptor afinity [1‐4]. From these studies we concluded that the 3‐[4‐(aryl)piperazin‐1‐yl]‐1‐(benzo[b]thiophen‐3‐yl)propane derivatives led to the best results. The continuation of this research project required the preparation of some new 3‐acyl‐5‐substituted benzo[b]thiophenes with a wide variety of substituents at the 5 position, ranging from nitro to hydroxyl derivatives. To obtain these derivatives we acylated the corresponding 5‐substituted benzo[b]thiophenes when it was possible.     

Synthesis and evaluation of antimicrobial and antioxidant activity of novel 7-Aryl-6H,7H- benzo[f]chromeno[4,3-b]chromen-6-one by MgO nanoparticle as green catalyst

Using MgO nanoparticle as a recyclable and efficient catalyst, multicomponent reaction of 2-Naphthol, aldehyde derivatives, 4-hydroxycoumarin has led to the synthesis of novel 7-Aryl-6H,7H- benzo[f]chromeno[4,3-b]chromen-6-one derivatives. This study aimed to examine the antimicrobial and antioxidant effects of the synthetic compound in order to reach some benefits, including the synthesis of new derivatives with biological properties, shorter time, high yields, and concordance with green chemistry.     

Synthesis,Structures, Resolution,and Chiroptical Properties of 1,16‐Diaryl‐Substituted Benzo[5]helicene Derivatives

An efficient route to the synthesis of benzo[5]helicene derivatives functionalized on the interior side of the helix was developed, and resulted in a series of 1,16‐diaryl‐substituted benzo[5]helicene derivatives starting from easily available 7‐methoxytetralone. X‐ray crystal structures showed that the benzo[5]helicene derivatives had highly helical, twisted structures, and could all create hierarchical packing architectures with alternating P and M layers in the solid state. Moreover, seven pairs of enantiomers based on 1,16‐diaryl‐substituted benzo[5]helicene derivatives were also obtained by efficient resolution through HPLC with semipreparative chiral columns. The enantiomers all showed clear mirror‐image circular dichroism (CD) spectra and high specific optical rotations, and their absolute configurations were determined by X‐ray crystallography. Interestingly, a helical nanotubular structure was formed by the self‐assembly of one enantiomer through halogen bonding. Furthermore, the enantiomers were found to have high racemization barriers and thermostability, which might be caused by the introduction of aryl substituents at the C1(C16) position.     

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.     

Indole and quinoline derivatives of 2,3-dihydro-l-benzothiepin-4(5H) one

By application of the Friedlander synthesis on 2,3-dihydro-l-benzothiepin-4(5H) one (4), the corresponding [4,5-b]quinoline derivatives 5a and 5b were obtained. Starting from the ketone (4) and by application of the Fischer indole synthesis, 1-benzolhiepino[4,5-b ]indole (6) and 1-benzothiepino[4,5-b]benzo[g]indole (7) were obtained. When β-naphthylhydrazine was used in the indolisation reaction, a mixture of 1-benzothiepino[4,5-b]benzo[e]indole ( 8 ) and 1-benzothiepino[4,3-b]benzo[e] indole (9) was obtained.     

Unexpected Novel Rearrangement Reaction: Synthesis of Benzo‐Medium‐Ring Anhydride

When we attempted to synthesize (E)‐3‐(benzo[d][1,3]dioxol‐5‐ylmethylene)‐4‐(propan‐2‐ylidene)‐dihydrofuran‐2,5‐dione, we found a novel rearrangement and obtained the unexpected compound that is assigned as benzo‐medium‐ring anhydride instead of the expected compound. We described the novel rearrangement and a potential method for the synthesis of benzo‐medium‐ring anhydride derivatives.     

Application of the aza-Wittig reaction for efficient synthesis of diversely substituted benzo[f]Chromeno[2,3-d]pyrimidine and benzo[f]chromeno[2,3-d][1,2,4]triazolopyrimidine derivatives

An efficient synthesis of novel benzo[f]Chromeno[2,3-d]pyrimidine and unknown benzo[f]chromeno[2,3-d][1,2,4]triazolopyrimidine derivatives is described utilizing ethyl-2-amino-4-phenyl-4H-benzo[f]chromene-3-carboxylate as precursor via aza-Wittig reaction. The process proved to be simple, high-yielding, and efficient.     

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.