Synthesis and Antimicrobial Activity of δ-Viniferin Analogues and Isosteres

The natural stilbenoid dehydro-δ-viniferin, containing a benzofuran core, has been recently identified as a promising antimicrobial agent. To define the structural elements relevant to its activity, we modified the styryl moiety, appended at C5 of the benzofuran ring. In this paper, we report the construction of stilbenoid-derived 2,3-diaryl-5-substituted benzofurans, which allowed us to prepare a focused collection of dehydro-δ-viniferin analogues. The antimicrobial activity of the synthesized compounds was evaluated against S. aureus ATCC29213. The simplified analogue 5,5′-(2-(4-hydroxyphenyl)benzofuran-3,5-diyl)bis(benzene-1,3-diol), obtained in three steps from 4-bromo-2-iodophenol (63% overall yield), emerged as a promising candidate for further investigation (MIC = 4 µg/mL).     

Design,synthesis and biological activity against estrogen receptor-dependent breast cancer of furo[1]benzofuran derivatives

The docking study on a series of furo[1]benzofuran derivatives with ERα has been demonstrated. The synthesis and characterization of a series of furo[1]benzofuran derivatives were described. All the target compounds were conducted to in vitro for the inhibitory activities against human breast cancer strains T-47D, MCF-7 and toxicity against human liver normal cell strains HL7702 via MTT assay. Most of the target compounds possessed anti-estrogen receptor-dependent breast cancer activities with weak toxicity to healthy cell strains. The preliminary structure–activity relationships were discussed.     

A novel one-pot three-component synthesis of benzofuran derivatives via Strecker reaction: Study of antioxidant activity

Abstract

A three-component Strecker-type reactions was applied for the synthesis of benzofuran derivatives through the reaction of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-yl)-1-ethanone (euparin), primary amines and trimethylsilyl cyanide (TMSCN) in the presence of catalytic amount of ZnO-nanorods (ZnO-NR) and piperidine in acetonitrile at room temperature. The method has proved to be synthetically simple, and effective with high atom economy and yield. The catalyst also revealed significant reusability. Moreover, the antioxidant activity and free radical scavenging capacity of the newly synthesized such as 4a, 4c, 6a and 6c was screened using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays and compared with hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). These compounds exhibit good DPPH radical scavenging and ferric reducing antioxidant power (FRAP) assays.     

Synthesis,characterization, and investigations of antimicrobial activity of benzopyrans,benzofurans and spiro[4.5]decanes

In this study, the radical cyclization reactions of cyclic 1,3-dicarbonyl compounds (1a–c) and α,β-unsaturated alcohols (2a–d) through Mn(OAc)₃ were performed. A series of biologically interesting dihydropyrans (3–5) and dihydrofurans (6–18) were synthesized as a result of these reactions. Spiro compounds (19–20) were obtained from the reactions of 1,3-dicarbonyl compounds and (E)-2,4-diphenyl-but-3-en-2-ol (2e). The unique structure of compound 19 was also confirmed by X-ray crystallography. In addition, the antibacterial activities of synthesized compounds were screened against some bacteria. Their zone diameters showed better results than some known antibiotics.     

One-pot multicomponent synthesis of functionalized 2,5-disubstituted-1,3,4-thiadiazine derivatives

An atom-efficient and environmentally friendly approach to the synthesis of 2,5-disubstituted-1,3,4-thidiazine derivatives has been developed. These compounds were synthesized by a reaction of 2-(2-bromoacetyl)benzofuran and thiocarbohydrazide with various aryl aldehydes, acetylacetones, and pthalic anhydrides in good yields. The advantages of this methodology are mild reaction conditions, easy workup procedure, clean reaction profile, shorter reaction time, and a wide range of substrate applicability. The structures of all synthesized compounds were confirmed from their analytical and spectral data.     

Oxidant‐Controlled Catalytic Transformations of Phenols with Unexpected Cleavage of Aromatic Rings

Oxidative transformations of phenols have attracted significant attention of chemists due to their importance in biological process and organic synthesis. In contrast to the relatively well‐developed oxygenation and coupling reactions of phenols, the highly efficient and selective oxidative ring cleavage of phenols is under‐represented. This work describes a novel CuCl‐catalyzed tandem homocoupling/skeletal rearrangement of phenols that realizes the cleavage of the phenol ring by using air or Ag₂CO₃ as the oxidant. Interestingly, simply changing the oxidant to K₂S₂O₈ results in the oxidative coupling/cyclization of phenols to give dibenzofurans. These results set an important precedent of oxidant‐controlled catalytic transformations of phenols.     

A Base-Mediated Approach Towards Dihydrofuro[2,3-b]Benzofurans from 2-Nitrobenzofurans and 1,3-Dicarbonyls

A straight-forward approach for the synthesis of a dihydrofuro[2,3-b]benzofuran derivatives has been achieved through a base-mediated Michael addition of 1,3-dicarbonyls to 2-nitrobenzofurans followed by intramolecular cyclization. A variety of 1,3-dicarbonyls, including cyclic as well as trifluoromethylated ones, have been subjected to react with 2-nitrobenzofurans under optimal conditions, and the respective dihydrofuro[2,3-b]benzofurans could be accessed in moderate to excellent yields.