Benzo[g]isoquinolinium benzoylmethylids

Stable benzo[g]isoquinolinium methylids were obtained from N-phenacylbenzo[g]isoquinolinium bromides and two of its benzene ring-substituted analogs. The first of these quaternary salts was converted to benzo[g]isoquinolinium dibenzoylmethylid. 3-Benzoyl-l,2-dicarbomethoxynaphth[2,3-g]indolizine was obtained from the same salt with dimethyl acetylenedicarboxylate (via a 1,3-dipolar cycloaddition reaction). Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 806–807, June, 1980     

Benzo[3,4]cyclobuta[1,2-b]thiophene

Tye synthesis of thieno[3,2-c]cinnoline is described; vapour phase thermolysis of this compound gives benzo[3,4]cyclobuta[1,2-b]thiophene.     

Synthesis of Benzo[a]Phenanthro[9,10-e]-Cyclooctene

A phenanthrene-fused cyclooctatetraene, namely benzo[a]phenanthro[9,10-e]cyclooctene has been synthesized by employing the “Reich-Paquette” procedure.     

Synthesis of [b]-Fused Benzo[d]furano Heterocycles

In the reactions of 3,4,6,7-tetrachloro-2,5-dihydroxy-2,3-dihydrobenzo[b]furan with 4-methyl and 4-phenyl thiosemicarbazides, dithizone and sodium N,N-diethyldithiocarbamate the [b]fused benzo[d]furano heterocycles have been synthesized.     

Benzo[h]cinnolin

The synthesis of benzo[h]cinnolin ( 3 ) is reported. Its spectroscopic properties (uv, luminescence, pmr, ms) are similar to the other diazaphenanthrenes containing a diazine ring. The lowering of the basicity of 3 compared with a monoazaphenanthrene like other diaza-aromatic compounds appears to be due to an electrostatic field effect and not to an inductive effect.     

Novel Route for Obtaining Isomeric Benzo[b]thiophenoindoles

We describe a novel route for synthesis of benzo[b]thiopheno[2,3-e]- and benzo[b]thiopheno[3,2-f]indoles. As the starting compounds, we used the corresponding annelated isatins obtained by the Sandmeyer reaction. We have established that reduction of the latter to the corresponding unsubstituted benzo[b]thiophenoindoles depends both on the nature of the substituent and on the reaction conditions.     

Benzo[b]thiophene derivatives. VIII. Benzo[b]thiophene-3-earboxaldehyde and derivatives

A procedure for the preparation of benzo[b]thiophene-3-carboxaldehyde from 3-methyl-benzo[b]thiophene is reported. This aldehyde behaves as a typical reactive aromatic aldehyde with respect to oxidation, reduction, the mixed Cannizzaro reaction, reductive amination and acyloin and other condensation reactions.     

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.     

[Au]/[Pd] Multicatalytic Processes: Direct One‐Pot Access to Benzo[c]chromenes and Benzo[b]furans

A new synthetic protocol that combines the advantages offered by eco‐friendly solvent‐free reactions and sequential transformations is reported. This strategy offers straightforward access to benzo[c]chromenes and benzo[b]furans from commercially available starting materials. This two‐step, one‐pot strategy consists of an Au‐catalyzed hydrophenoxylation process followed by Pd‐catalyzed C?H activation or Mizoroki–Heck reactions. The selectivity of the process towards C?H activation or Mizoroki–Heck reaction can be easily tuned.     

Synthesis of Boronate‐Based Benzo[fg]tetracene and Benzo[hi]hexacene via Demethylative Direct Borylation

A demethylative direct borylation is reported, which was applied to the synthesis of benzo[fg]tetracenes containing boronate ester, amide, and thioester substructures. Depending on the heteroatom adjacent to boron, the molecules showed characteristic photophysical properties, molecular arrangements, and chemical stabilities. The key to the successful synthesis is the appropriate choice of the boron source and Brønsted base. The versatility of the direct borylation was demonstrated by the synthesis of a boronate‐based benzo[hi]hexacene.     

Benzo[c,d]indole carbocyanines

A symmetrical and some asymmetrical carbocyanines (benzo[c,d]indole derivatives) were synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 340–341, March, 1973.     

Reactions of 1-Substituted Benzo[4,5]imidazo[1,2-a]pyridines

Bromination of 1-oxo(imino, amino)benzo[4,5]imidazo[1,2-a]pyridines gave the corresponding 2-bromo derivatives. Acylation using the Vilsmeier complex in acetic anhydride gave the N-formyl and N-acetyl derivatives. The reaction of the amine with the Vilsmeier complex, acetyl acetone, ethyl acetoacetate, and 2,5-dimethoxytetrahydrofuran occurs at the amino group.     

Synthesis and Characterization of Thienothiophene Conjugated Benzo[c]Thiophene Analogs

Syntheses of thienothiophene tethered benzo[c]thiophene analogs starting from thienothiophenyl lactone are reported. The benzo[c]thiophenes containing thienothiophene unit upon Vilsmeier–Haack formylation followed by condensation with malononitrile/thiophene‐2‐acetonitrile furnished corresponding cyano‐vinylenes. Optical and electrochemical properties of thienothiophene conjugated benzo[c]thiophene analogs are correlated with their structures.     

Benzo[B]thiophene derivatives XXIV. Oxidation of o-dihydroxybenzo[b]thiophene methyl ethers

The attempted oxidative demethylation of a series of o-dihydroxybenzo[b]thiophene methyl ethers with cerium (IV), argentic oxide, periodale and thallate usually led to intractable mixtures. However, in one ease, use of ceric ammonium nitrate resulted in nitration of the benzo[b]-thiophene ring. In another example, treatment with aqueous periodate or thallate resulted in oxidative hydroxylation of benzo[b]thiophene.     

Benzo[b]Furan in the Povarov Reaction

The Povarov-type condensation of ethyl 2-(arylimino)acetates, 1-aryl-2-aryliminoethanones or N-benzylideneanilines with benzo[b]-furan affords 5,6,6a,11b-tetrahydrobenzofuro[2,3-c]quinolines and/or related benzofuro[2,3-c]quinolines.     

Ionic Liquid-Mediated Facile Synthesis and Antimicrobial Study of Thiazolo [2,3-b]Benzo[h]Quinazolines and Thiazino[2,3-b] Benzo-[h]Quinazolines

Abstract

8-Methoxy-4-phenyl-3,4,5,6-tetrahydrobenzo[h]quinazoline-2(1H)-thione, obtained by the condensation of 2-benzylidene-6-methoxy-3,4-dihydronapthalene-1(2H)-one with thiourea, on reaction with chloroacetic acid and 3-chloropropanoic acid in the presence of the ionic liquid N-methylpyridinium tosylate furnishes 3-methoxy-7-phenyl-7,10-dihydro-5H- benzo[h]thiazolo[2,3-b]quinazoline-9(6H)-one and 3-methoxy-7-phenyl-5,6,10,11-tetrahydro- benzo[h][1,3]thiazino[2,3-b]quinazoline-9(7H)-one. Further, condensation of the thione with 1,2-dibromoethane and 1,3-dibromopropane yields 3-methoxy-7-phenyl-6,7,9,10-tetrahydro-5 H-benzo[h]thiazolo[2,3-b]quinazoline and 3-methoxy-7-phenyl-5,6,7,9,10,11-hexahydrobenzo [h][1,3]thiazino[2,3-b]quinazoline respectively. Arylidene derivatives have been obtained by two routes. The structures of the cyclized compounds have been established on the basis of elemental analysis and spectroscopic data. The synthesized compounds were screened for antimicrobial activity. Some of the compounds showed promising antimicrobial activities.     

Efficient Synthetic Approach to Substituted Benzo[b]furans and Benzo[b]thiophenes by Iodine‐Promoted Cyclization of Enaminones

An efficient synthetic approach to the substituted benzo[b]furan and benzo[b]thiophene scaffolds by iodine‐mediated cyclization of the corresponding enaminones is described. This protocol was applied to a large series of these latter precursors to afford the respective benzoheterocycles substituted at the C‐2 position by a carbonyl group functionality. A study of the factors that control this process reveals that the reactivity depends on the presence of electron‐donor groups in the aryl ring of the aryloxycarbonylic and arylthiocarbonylic moieties.     

2-取代苯并噻吩类化合物合成研究进展

2-取代苯并噻吩广泛的存在于天然产物中,独特的分子结构使其表现出了较高的药理和生物活性,常被用于药物化学和材料化学中。已有多种具有苯并噻吩骨架药物用于临床,故具有极高的研究价值。本文结合国内外学者对这方面的相关研究,重点对2-苯基苯并噻吩、2-酰基苯并噻吩和2-氨基苯并噻吩类化合物的合成方法进行了综述。     

Tandem Synthesis of Benzo[b]carbazoles and Their Photoluminescent Properties

5 H‐Benzo[b]carbazoles were prepared through a tandem reaction between 2‐ethynyl‐N‐triphenylphosphoranylidene anilines and α‐diazoketones through ketenimine intermediates in moderate‐to‐good yields. By using this approach, benzo[b]benzo[5,6]indolo[3,2‐h]carbazoles, fluoreno[9,1‐ab]carbazoles, and fluoreno[9,1‐ab]fluoreno[1′,9′:5,6,7]indolo[3,2‐h]carbazoles were constructed in one pot. Moreover, the resulting products emitted light within the range 410–521 nm, with quantum yields of up to 62 %.     

Spectrometry: Spectrofluorimetric Study of Benzo[a]Quinolizidines as Potential Fluorescent Probes for DNA

Abstract

The interaction between DNA and several benzo[a]quinolizidines, including emetine and four synthetic benzo[a]quinolizidine derivatives, has been studied using spectrophotometric and spectrofluorimetric techniques. An appreciable decrease in molar absorptivity at the maxima at λ = 230 nm and λ = 280 nm is observed when increasing DNA concentrations (10 mg/ml-100 mg/ml) are added to aqueous buffered solutions (pH = 7) of the benzo[a]quinolizidine derivatives. These compounds exhibit native fluorescence at 315 nm (λex = 285 nm), which is quenched by increasing amounts of DNA. The interaction between DNA and benzo[a]quinolizidines was confirmed by viscosimetry. Increases between 1.9% and 10.8% in the reduced specific viscosity (n/no) of DNA solutions were observed due to the presence of the benzo[a]quinolizidines studied.