A series of 3,3-arylidene bis(4-hydroxycoumarins) were synthesized by the reaction of aromatic aldehydes with 4-hydroxycoumarin using dodecylbenzenesulfonic acid as Br?nsted acid-surfactant catalyst in aqueous media a...A series of 3,3-arylidene bis(4-hydroxycoumarins) were synthesized by the reaction of aromatic aldehydes with 4-hydroxycoumarin using dodecylbenzenesulfonic acid as Br?nsted acid-surfactant catalyst in aqueous media and under microwave irradiation. The present method is operationally simple and the use of water as the reaction medium makes the process environmentally benign.展开更多
3-((2E)-3(aryl)prop-2-enoyl)-2H-chromen-2-one 3 was synthesized from 4-hydroxy coumarin by refluxing 3-acetyl-4-hydroxy coumarin with aromatic aldehydes in chloroform in the presence of a catalytic amount of piperidin...3-((2E)-3(aryl)prop-2-enoyl)-2H-chromen-2-one 3 was synthesized from 4-hydroxy coumarin by refluxing 3-acetyl-4-hydroxy coumarin with aromatic aldehydes in chloroform in the presence of a catalytic amount of piperidine. 3 was converted to pyrazoles 4, 5 by treatment with hydrazine and phenylhydrazine in toluene, respectively. The structures of the new compounds were confirmed by elemental analysis, IR, and multinuclear/multidimensional NMR spectroscopy (1H, 13C-NMR, NOESY, HMBC) which allowed us to assign the complete network of proton and carbon atoms. All the compounds exhibited one quasireversible redox process. All the newly synthesized compounds were screened for their antibacterial and antioxidant activities. Antimicrobial studies revealed that 3-(5-(2,5-dimethylphenyl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-4- hydroxy-2H-chromene-2-one 5c showed significant antibacterial activity against Escherichia coli and Pseudomonas Aeruginosa 27853. Furthermore, 3-(5-(aryl)-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-2H-chromene- 2-ones 4, 5 showed antioxidant activities of different extents with respect to individual compounds as well as to the antioxidant methods. The 3-(5-(phenyl)-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-2H-chromene-2-ones 4a was found to be the most active antioxidant in the series and more active than trolox which makes the investigated complexes a new promising class of antibacterial compounds.展开更多
α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of ...α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].展开更多
A novel one-pot synthesis of furo[3,2-c]coumarins has been developed from readily available starting materials 4-hydroxycoumarin and arylglyoxal. This method is simple, rapid and good yielding.
A series of novel 3-substituted-4-hydroxycoumarin derivatives 6（a-1） were synthesized in high yield using one-pot three component coupling reaction catalyzed by ceric ammonium nitrate. These compounds were evaluated...A series of novel 3-substituted-4-hydroxycoumarin derivatives 6（a-1） were synthesized in high yield using one-pot three component coupling reaction catalyzed by ceric ammonium nitrate. These compounds were evaluated for antileishmanial activity against Leishmania donovani promastigotes and antioxidant activity（DPPH-radical scavenging activity）. Two compounds, 6h（IC50= 9.90 μmol/L） and 6i（IC50= 6.90 μmol/L） displayed potent antileishmanial activity when compared with standard antileishmanial agents pentamidine（IC50= 16.15 μmol/L） and miltefosine（IC50= 12.50 μmol/L）. Three compounds, 6c（IC50= 10.79 μmol/L）, 6h（IC50= 10.60 μmol/L）, and 6i（IC50= 10.73 μmol/L） showed significant antioxidant activity favorably with the antioxidant standards butylated hydroxy toluene（IC50= 16.47 μmol/L） and ascorbic acid（IC50= 12.69 μmol/L）. A molecular docking study of compounds 6（a-1） suggested a possible mode of binding with the Adenine phosphoribosyltransferase enzyme of L.donovani. ADME properties were predicted in silico and support the potential of 6（a-1） to show favorable drug-like properties.展开更多
Copper oxide nanoparticles showed excellent catalytic activity through three-component condensation reaction of aldehydes, malononitrile,and 4-hydroxycoumarin for the synthesis of 3,4-dihyropyrano[c]chromenes in water...Copper oxide nanoparticles showed excellent catalytic activity through three-component condensation reaction of aldehydes, malononitrile,and 4-hydroxycoumarin for the synthesis of 3,4-dihyropyrano[c]chromenes in water medium in excellent yields and very short reaction times.展开更多
This paper describes the combustion synthesis ofα-Fe2O3 nanopowder at much lower temperature and its catalytic activity for the one-pot preparation of 3,4-dihydropyrano[c]chromenes.The combustion derivedα-Fe_2O_3 na...This paper describes the combustion synthesis ofα-Fe2O3 nanopowder at much lower temperature and its catalytic activity for the one-pot preparation of 3,4-dihydropyrano[c]chromenes.The combustion derivedα-Fe_2O_3 nanopowder was characterized by powder X-ray diffraction（PXRD）,Braunauer,Emmett and Teller（BET） surface area,scanning electron microscopy（SEM） and Fourier transform infrared spectroscopy（FTIR）.Highly efficient,three-component condensation of aromatic aldehyde,malanonitrile and 4- hydroxycoumarin catalyzed byα-Fe2O3 nanoparticles at room temperature is described.The method offers an excellent alternative to the synthesis of 3,4-dihydropyrano[c]chromenes.The reactions are rapid,clean,and the products with good yield and high purity.展开更多
A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The...A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst.展开更多
文摘A series of 3,3-arylidene bis(4-hydroxycoumarins) were synthesized by the reaction of aromatic aldehydes with 4-hydroxycoumarin using dodecylbenzenesulfonic acid as Br?nsted acid-surfactant catalyst in aqueous media and under microwave irradiation. The present method is operationally simple and the use of water as the reaction medium makes the process environmentally benign.
文摘3-((2E)-3(aryl)prop-2-enoyl)-2H-chromen-2-one 3 was synthesized from 4-hydroxy coumarin by refluxing 3-acetyl-4-hydroxy coumarin with aromatic aldehydes in chloroform in the presence of a catalytic amount of piperidine. 3 was converted to pyrazoles 4, 5 by treatment with hydrazine and phenylhydrazine in toluene, respectively. The structures of the new compounds were confirmed by elemental analysis, IR, and multinuclear/multidimensional NMR spectroscopy (1H, 13C-NMR, NOESY, HMBC) which allowed us to assign the complete network of proton and carbon atoms. All the compounds exhibited one quasireversible redox process. All the newly synthesized compounds were screened for their antibacterial and antioxidant activities. Antimicrobial studies revealed that 3-(5-(2,5-dimethylphenyl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-4- hydroxy-2H-chromene-2-one 5c showed significant antibacterial activity against Escherichia coli and Pseudomonas Aeruginosa 27853. Furthermore, 3-(5-(aryl)-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-2H-chromene- 2-ones 4, 5 showed antioxidant activities of different extents with respect to individual compounds as well as to the antioxidant methods. The 3-(5-(phenyl)-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-2H-chromene-2-ones 4a was found to be the most active antioxidant in the series and more active than trolox which makes the investigated complexes a new promising class of antibacterial compounds.
文摘α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].
文摘A novel one-pot synthesis of furo[3,2-c]coumarins has been developed from readily available starting materials 4-hydroxycoumarin and arylglyoxal. This method is simple, rapid and good yielding.
文摘A series of novel 3-substituted-4-hydroxycoumarin derivatives 6（a-1） were synthesized in high yield using one-pot three component coupling reaction catalyzed by ceric ammonium nitrate. These compounds were evaluated for antileishmanial activity against Leishmania donovani promastigotes and antioxidant activity（DPPH-radical scavenging activity）. Two compounds, 6h（IC50= 9.90 μmol/L） and 6i（IC50= 6.90 μmol/L） displayed potent antileishmanial activity when compared with standard antileishmanial agents pentamidine（IC50= 16.15 μmol/L） and miltefosine（IC50= 12.50 μmol/L）. Three compounds, 6c（IC50= 10.79 μmol/L）, 6h（IC50= 10.60 μmol/L）, and 6i（IC50= 10.73 μmol/L） showed significant antioxidant activity favorably with the antioxidant standards butylated hydroxy toluene（IC50= 16.47 μmol/L） and ascorbic acid（IC50= 12.69 μmol/L）. A molecular docking study of compounds 6（a-1） suggested a possible mode of binding with the Adenine phosphoribosyltransferase enzyme of L.donovani. ADME properties were predicted in silico and support the potential of 6（a-1） to show favorable drug-like properties.
文摘Copper oxide nanoparticles showed excellent catalytic activity through three-component condensation reaction of aldehydes, malononitrile,and 4-hydroxycoumarin for the synthesis of 3,4-dihyropyrano[c]chromenes in water medium in excellent yields and very short reaction times.
基金VTU(VTU/Aca./2009-10/A-9/11714) for the financial support and Chemistry-TEQIP Laboratory of MSRIT and SSMRV College, Chemistry Research Center
文摘This paper describes the combustion synthesis ofα-Fe2O3 nanopowder at much lower temperature and its catalytic activity for the one-pot preparation of 3,4-dihydropyrano[c]chromenes.The combustion derivedα-Fe_2O_3 nanopowder was characterized by powder X-ray diffraction（PXRD）,Braunauer,Emmett and Teller（BET） surface area,scanning electron microscopy（SEM） and Fourier transform infrared spectroscopy（FTIR）.Highly efficient,three-component condensation of aromatic aldehyde,malanonitrile and 4- hydroxycoumarin catalyzed byα-Fe2O3 nanoparticles at room temperature is described.The method offers an excellent alternative to the synthesis of 3,4-dihydropyrano[c]chromenes.The reactions are rapid,clean,and the products with good yield and high purity.
基金Firoozabad University Research Council for the partialfinancial support
文摘A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris（hydrogen sulfate） as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst.
