Chemodivergent Synthesis of Benzofurans and 2,3-Dihydrobenzofurans via Tandem Oxidative Annulation of Enaminones and Salicylaldehydes

Chemodivergent synthesis of benzofurans and 2,3-dihydrobenzofurans has been realized.Under a reaction system consisting of DBDMH and K_(2)CO_(3) as promotors,controlled conditions enabled the formation of two sets of valuable heterocycles from the tandem transformation of enaminones and salicylaldehydes.The key to success was the identification of the reaction parameters,in which the imine intermediate which was formed by transient halogenation coupling and substitution processes underwent either aldol condensation/annulation or imine hydrolysis/aldol condensation.The additives NH_(4)Cl or Fe_(2)(SO_(4))_(3) controlled the unique selectivity of this reaction.A broad substrate scope of enaminones and salicylaldehydes has been employed in this reaction,demonstrating excellent functional group tolerance and versatility.

Metal-free visible-light-induced oxidative cyclization reaction of 1,6-enynes and arylsulfinic acids leading to sulfonylated benzofurans

A new and convenient visible-light-induced method has been developed for the synthesis of sulfonylated benzofurans via oxidative cyclization reaction of 1,6-enynes and arylsulfinic acids.This reaction was carried out under metal-free and mild conditions,in which the C-S,C-C and C=O bonds could be sequentially formed in one pot operation.

One-Pot Three-Component Synthesis of 2-Methyl-3-aminobenzofurans Using Calcium Carbide as a Concise Solid Alkyne Source

A one-pot three-component method for the synthesis of 2-methyl-3-aminobenzofurans using calcium carbide as a concise solid alkyne source,and salicylaldehydes and secondary amines as starting materials is described.This protocol has salient feature of the use of inexpensive,abundant and easy-to-handle alkyne source,avoiding the use of inflammable and explosive acetylene gas as an original alkyne source.In addition,step economy,satisfactory yield,and simple work-up procedure are also advantages of this route.

Catalytic asymmetric brominative dearomatization reaction of benzofurans

A catalytic asymmetric brominative dearomatization reaction of benzofuran derivatives was achieved by using hydroquinidine 1,4-phthalazinediyl diether [（DHQ）_2PHAL] as the catalyst and N-bromoacetamide（NBAc） as the brominating reagent. A series of brominated spiro[benzofuran-2,5＇-oxazoles] bearing two contiguous stereogenic centers were obtained in high yields（up to 99%） with excellent enantioselectivity（up to 97% ee）.

Nickel-Catalyzed Reductive Electrophilic Ring-Opening of Benzofurans with Alkyl Halides

In this paper,we developed an electrophilic ring-opening reaction,which is beyond the strained small ring system.Under reductive nickel catalysis,ring-opening of diverse benzofurans via endocyclic inert carbon–oxygen bond cleavage can be achieved with an array of inactivated secondary and tertiary alkyl halides as coupling partners,allowing for the preparation of a series of(E)-o-alkenylphenols with excellent E/Z-selectivity and high functional tolerance.The utility of this method was further demonstrated through derivatizations of the ring-opening products using the o-hydroxyl group as a functional handle,providing various organic compounds in good to high efficiency.

Mechanisms mediating cholinergic antral circular smooth muscle contraction in rats

AIM:To investigate the pathway(s)mediating rat antral circular smooth muscle contractile responses to the cholinomimetic agent,bethanechol and the subtypes of muscarinic receptors mediating the cholinergic contraction. METHODS:Circular smooth muscle strips from the antrum of Sprague-Dawley rats were mounted in muscle baths in Krebs buffer.Isometric tension was recorded.Cumulative concentration-response curves were obtained for(+)-cis- dioxolane(cD),a nonspecific muscarinic agonist,at 10^(-8)- 10^(-4)mol/L,in the presence of tetrodotoxin(TTX,10^(-7)mol/L). Results were normalized to cross sectional area.A repeat concentration-response curve was obtained after incubation of the muscle for 90 min with antagonists for M1(pirenzepine), M2(methoctramine)and M3(darifenadn)muscarinic receptor subtypes.The sensitivity to PTX was tested by the ip injection of 100 mg/kg of PTX 5 d before the experiment.The antral circular smooth muscles were removed from PTX-treated and non-treated rats as strips and dispersed smooth muscle cells to identify whether PTX-linked pathway mediated the contractility to bethanechol. RESULTS:A dose-dependent contractile response observed with bethanechol,was not affected by TTx.The pretreatment of rats with pertussis toxin decreased the contraction induced by bethanechol.Lack of calcium as well as the presence of the L-type calcium channel blocker,nifedipine,also inhibited the cholinergic contraction,with a reduction in response from 2.5±0.4 g/mm^2 to 1.2±0.4 g/mm^2(P<0.05).The dose- response curves were shifted to the right by muscarinic antagonists in the following order of affinity:darifenacin (M_3)>methocramine(M_2)>pirenzepine(M_1). CONCLUSION:The muscarinic receptors-dependent contraction of rat antral circular smooth muscles was linked to the signal transduction pathway(s)involving pertussis-toxin sensitive GTP-binding proteins and to extracellular calcium via L-type voltage gated calcium channels.The presence of the residual contractile response after the treatment with nifedipine,suggests that an additional pathway could mediate the cholinergic contraction.The involvement of more than one muscarinic receptor(functionally predominant type 3 over type 2)also suggests more than one pathway mediating the cholinergic contraction in rat antrum.

Two new benzofuran lignan glycosides from Gelsemium elegans

Two new benzofuran lignan glycosides, gelsemiunoside A and B, were isolated from the whole plant of Gelsemium elegans Benth. Their structures were elucidated on the basis of spectroscopic evidence. Furthermore, gelsemiunoside A and B were shown a potent cytotoxic activity by suppressing the proliferation of A375-S2 cells.

In vitro antiplasmodial activity of Spiro benzofuran compound from mangrove plant of Southern India

Objective:To find out the in vitro antipalsmodial activities of mangrove leaf extracts.Methods: In vitro antiplasmodial assay was carried out with 13 different mangrove plants.Column chromatography was performed with the most potent Agecerious corniculatum（A.corniculatum） by using various solvent extractions.GC-MS was also preformed with the most potent ethanolic fraction of the A.corniculatum extract.Results:Of the 13 mangroves plants, A.corniculatum showed maximum percentage of parasitemia suppression（94.98±1.16）%.Column chromatography was performed with A.corniculatum with different solvents and the methanolic extract showed maximum percentage（99.73±1.63）%of parasitemia inhibition at 150μg/mL concentration with the IC50 value of（29.28±3.23）μg/mL concentration.The results of the GC-MS analysis observed that,the most potent methanolic extract showed maximum retention time（30.687 RT） and the chemical class was identified as Spiro[benzofuran-2（3 H）,1’-（3 cyclohexane）-2’,3- dione,7-chloro-4’,6]which was responsible for the antiplasmodial activity.Conclusions:It is concluded from the present study that,the chemical constituents of A.corniculatum collected from Pichavaram mangrove forest can be used as a putative antiplasmodial drugs in future.

Unexpected Synthesis of 2,2'-[1-(4-Methoxyphenoxy)propane-2,2-diyl]bis(5-methoxy-3-methylbenzofuran)

A new bisbenzofuran analogue Ⅶ was achieved unexpectedly in one step procedure from 1-（4-methoxyphenoxy）acetone Ⅰ by using Amberlyst 15 resin as catalyst in excellent yield. The structure was elucidated by spectroscopy analysis including ^1H-NMR, ^13C-NMR, DEPT, ESI-MS, element analysis.

Preparation of Ni2P/Al-SBA-15 catalyst and its performance for benzofuran hydrodeoxygenation

The Al-doped Ni2P/AI-SBA-15 catalyst with high hydrodeoxygenation （HDO） activity was synthesized by tem- perature programmed reduction at a relatively low reduction temperature of 400 ℃. The as-prepared catalyst was characterized by X-ray diffraction （XRD）, H2 temperature-programmed reduction （H2-TPR）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscope （TEM）, NH3 temperature programmed desorption （NH3-TPD）, N2 adsorption-desorption and CO uptake. The effect of AI on benzofuran （BF） HDO performance was investigated. The result indicates that the incorporation of AI into the SBA-15 support can promote the formation of much uniform, smaller, highly dispersed N2P particles on the catalyst. The AI also contrib- utes to suppress the enrichment of P and promote more exposed Ni sites on the surface. In addition, the incorporation of AI can enhance the acid strength. The total deoxygenated product yield over Ni2P/AI-SBA-15 reached 90.3%, which is an increase of 19.4%, when compared with that found for Ni2P/SBA-15 （70.9%）.

An efficient synthesis of benzofuran derivatives under conventional/non-conventional method

l-Methyl-3-ethyl imidazolium bromide[meim]Br/basic alumina（Al2O3） has been found to promote the cyclocondensation of chloroacetone/chloroethyl acetate with salicylaldehydes under conventional as well as microwave irradiation to yield benzofuran derivatives.

Two New Benzofuran Derivatives from Ligularia stenocephala

Two new benzofuran derivatives were isolated from the roots of Ligularia stenocephala. Their structures were established by spectroscopic methods and 2D NMR experiments.

Effect of captopril or verapamil on intracellular sodium in cultured vascular smooth muscle cells

The effects of captopril (Cap) and verapamil (Ver)alone and in combination on intracellular Na+ concentration ([Na+]i) in cultured aortic smooth muscle cells (ASMC) of rabbits was evaluated by a direct measurement of [Na+]i with fluorescent dye sodium-binding benzofuran isophthalate (SBFI) combined with digital image. [Na+]i in resting cells was found to be 11.9 ± 0. 7 mmol/L. Angiotensin II (Ang-II, 0.1-10μmol/L) induced an increase of [Na+]i in concentration-dependent manner. Ver (0.1-10μmol/L) inhibited Ang-II (1 μmol/L)-induced increase in [Na+]i, while Cap enhanced Ang-II-induced increase in [Na+]i at 10μmol/L but not at 0.1-1μmol/L. Ver (0.1-1μmol/L)abolished enhancement of Ang-II-induced increase in [Na+]i by Cap. Thus, the inhibition of Capenhanced [Na+]i by Ver may provide a new hypothesis for the underlying molecular mechanism of synergistic effect of the combination of Ca2+ antagonists and angiotensinconverting enzyme inhibitors in controlling blood pressure.

THE SYNTHESES OF BENZOFURAN DERIVATIVES

Two benzofuran derivatives were synthesized from 3,4-bis(trimethylsilyl) furan after a series of reactions. Their structures were identified by 1H NMR, 13C NMR, MS and EA.

Synthesis and Crystal Structure of (5-Hydroxy-6-methoxybenzofuran-3-yl)-(4-methoxyphenyl)methanone

Compound 1 （5-hydroxy-6-methoxybenzofuran-3-yl）（4-methoxyphenyl）metha- none, C17H1405, as a potential anti-breast cancer agent has been synthesized under microwave irradiation, which was further converted to （5,6-dihydroxybenzofuran-3-yl）（4-methoxyphenyi）me- thanone （2）. The compounds were characterized by MS and NMR spectra. Meanwhile, the crystal of 1 was obtained and determined by X-ray single-crystal diffraction. Crystal data： monoclinic system, space group P2/n, a = 8.908（6）, b = 10.505（7）, c = 15.452（11） A, β = 105.043（9）, V = 1396.4（16） A3, Z = 4, F（000） = 624, Dc = 1.419 g/cm3, p = 0.105 mm-1, R = 0.0513 and wR = 0.1246 for 14459 independent reflections （Rint = 0.0647） and 2488 observed ones （I〉 2σ（/））. lntermolecular O-H...O and π-π stacking interactions contributed to the stability of the structure.

Heterocyclic Synthesis via Enaminones: Synthesis and Molecular Docking Studies of Some Novel Heterocyclic Compounds Containing Sulfonamide Moiety

4-Acetyl-N, N-diethylbenzenesulfonamide (1) was condensed with dimethylformamide dimethy-lacetal (DMF-DMA) to yield the enaminone, which reacts readily with different reagents to give the corresponding pyrazoles, triazolopyrimidine, imidazopyridine, pyrimidopyrimidine, pyrazolopyrimidine, benzofuran, pyranone, pyridine, pyrimidine and pyrazolopyridazine derivatives. These compounds were designed to comply with the general features of sulfonamide pharmacophore which act as Cyclooxygenase (COX-2) inhibitors. Virtual screening using molecular docking studies of the synthesized compounds was performed by (MOE), the molecular docking results indicate that, some synthesized compounds suitable inhibitor against (COX-2) with further modification.

Crystal and Molecular Structure of N-[2-(6-Methoxy-2-oxo-2H-Chromen-4-yl-Benzofuran-3-yl]- Benzamide

The crystal structure of the potential active N-[2-(6-Methoxy-2-oxo-2H-chromen-4-yl)-benzofuran-3-yl]-benzamide (C25H17NO5) (I) has been determined from single crystal X-ray diffraction data. The title compound crystallizes in the monoclinic space group P 21/n, with a = 12.0551(11), b = 9.7853(8), c = 16.6517(16) , β = 90.092(4)o, V = 1964.28(3) 3, Dcalc = 1.391 Mg/m3, Z = 4. In the structure, intermolecular H-bonds lead to the formation of a centrosymmetric dimer of the molecule. There is an intramolecular C7—H7…N1 hydrogen bond forming a closed seven membered ring. There are also intramolecular π-π interactions presented between the 3,6-Dihydro-2H-pyran ring of the chromen moiety [Cg2…Cg2 distance = 3.5812(13) ]. The packing structure is stabilized by these C—H…N, N—H…O hydrogen bonds, C—H… π and π…π interactions.

Synthesis, Crystal Structure and Biological Activity of 2-((2,2-Dimethyl-2,3-dihydrobenzofuran-7-yl)oxy)-N-(3-(furan-2-yl)-1-phenyl-1H-pyrazol-5-yl)acetamide

The title compound 2-（（2,2-dimethyl-2,3-dihydrobenzofuran-7-yl）oxy）-N-（3-（furan-2-yl）-1-phenyl-1H-pyrazol-5-yl） acetamide（C25H23N3O4, Mr = 429.46） has been synthesized, and its structure was characterized by 1H-NMR, 13C-NMR, H RMS, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 20.6205（18）, b = 5.2930（5）, c = 18.9282（17） A, β = 94.089（2）°, V = 2060.6（3） A^3, Z = 4, Dc = 1.384 g/cm^3, μ（Mo Ka） = 0.71073 mm^-1, F（000） = 904, R = 0.0345 and w R = 0.0930. The intramolecular hydrogen bond at N（1）–H（1）…O（2）, intermolecular weak interactions at O（3）…H（4） and weak π-π interactions connected the molecules to lead to one-dimensional tapes. Bioassay results indicated that the title compound had moderate herbicidal and fungicidal activities.

Research Progress on the Synthesis of Benzofuran Based on Cyclization Strategy

Benzofuran is an essential structural component found in a wide range of natural products,agrochemicals and drugs,possessing a range of biological activities.In recent years,there have been numerous reports of successful syntheses of benzofuran derivatives via intra-and inter-molecular cyclizations using diverse catalysts.This review gives an exhaustive and methodical survey of the procedures for making benzofurans.

Phenolic constituents and anticancer properties of Morus alba(white mulberry) leaves

Flavonoids are by far the most dominant class of phenolic compounds isolated from Morus alba leaves(MAL). Other classes of compounds are benzofurans, phenolic acids, alkaloids, coumarins, chalcones and stilbenes. Major flavonoids are kuwanons, moracinflavans, moragrols and morkotins. Other major compounds include moracins(benzofurans), caffeoylquinic acids(phenolic acids) and morachalcones(chalcones). Research on the anticancer properties of MAL entailed in vitro and in vivo cytotoxicity of extracts or isolated compounds. Flavonoids, benzofurans, chalcones and alkaloids are classes of compounds from MAL that have been found to be cytotoxic towards human cancer cell lines. Further studies on the phytochemistry and anticancer of MAL are suggested. Sources of information were Pub Med,Pub Med Central, Science Direct, Google, Google Scholar, J-Stage, Pub Chem and China National Knowledge Infrastructure.