Promoted and mediated by an ionic liquid-[bmim][BF4], fused pyrans or arylbis（4-hydroxy-6-methyl-2-oxo-2H-pyran-3- yl）methanes were efficiently and selectively prepared from the reaction of aldehyde and 4-hydroxy-6-...Promoted and mediated by an ionic liquid-[bmim][BF4], fused pyrans or arylbis（4-hydroxy-6-methyl-2-oxo-2H-pyran-3- yl）methanes were efficiently and selectively prepared from the reaction of aldehyde and 4-hydroxy-6-methyl-2-oxo-pyran with or without acetic anhydride. By using these novel procedures, pyrimidine nucleoside-fused pyran and arylbis（pyranon-3-yl）methane hybrids with potential biological activities were constructed.展开更多
A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and m...A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and malononitrile in water using H6P2W18O62á18H2O as catalyst.Reusability of the catalyst and reaction media,short reaction times and easy isolation of products are some added advantages of the present methodology.展开更多
4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succin...4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid.This method has the advantages of high yield,clean reaction,simple methodology and short reaction time.The catalyst could be recycled without significant loss of activity.展开更多
A ligand free, Palladium nanoparticles catalyzed synthesis of pyran derivatives using C-H activated compound, malononitrile and aryl aldehyde via Knoevenagel condensation followed by Michael addition reaction using Pa...A ligand free, Palladium nanoparticles catalyzed synthesis of pyran derivatives using C-H activated compound, malononitrile and aryl aldehyde via Knoevenagel condensation followed by Michael addition reaction using Palladium nanoparticles as catalyst in one-pot is described herein. The advantages of this method lie in its simplicity, low catalyst loading, cost effectiveness and easy to handle. The Palladium Nanoparticles can be reused without loss of activity even after recycling four times. The palladium nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM). The present method also allows us to synthesize highly functionalized title compounds from simple and readily available inputs.展开更多
Diammonium hydrogen phosphate and potassium carbonate-catalyzed one-pot synthesis of 1,4- phenylene-bis（2-amino-4H-pyran-3-carbonitrile and 2-amino-4-aryl-4H-pyran-3-carbonitrile deriva- tives has been achieved by a ...Diammonium hydrogen phosphate and potassium carbonate-catalyzed one-pot synthesis of 1,4- phenylene-bis（2-amino-4H-pyran-3-carbonitrile and 2-amino-4-aryl-4H-pyran-3-carbonitrile deriva- tives has been achieved by a three-component cyclocondensation of aldehydes, malononitrile, and different nucleophiles in aqueous medium in high yields.展开更多
A rapid and facile preparation of benzo-[b]-pyran derivatives through condensation of chalcone and 5, 5-dimethyl-1,3-cyclohexandione under microwave irradiation in the presence of catalytic amount of InCl3·4H2O h...A rapid and facile preparation of benzo-[b]-pyran derivatives through condensation of chalcone and 5, 5-dimethyl-1,3-cyclohexandione under microwave irradiation in the presence of catalytic amount of InCl3·4H2O has been developed. With its high efficiency, operational simplicity and environmental benignancy, this method may provide a useful alternative for the preparation of benzo-[b]-pyran derivatives.展开更多
A series of novel pleuromutilin derivatives with 4H-pyran-4-one and pyridin-4-one substitution in the C-14 side chain have been designed and synthesized. In vitro antibacterial activity evaluation showed that most of ...A series of novel pleuromutilin derivatives with 4H-pyran-4-one and pyridin-4-one substitution in the C-14 side chain have been designed and synthesized. In vitro antibacterial activity evaluation showed that most of the derivatives exhibited potent antibacterial activity against drug resistant Gram-positive strains. Compounds 12 a, 12 d, and 28 are the most active derivatives in this series, displaying activity comparable to that of retapamulin and BC-3781. As the metabolic stability of this series is not satisfactory, further modifications are going on to improve their pharmacokinetic profile.展开更多
Condensation of β-Oxoanilide 1 with active methylene derivatives 2a,bafforded the pyridine derivative 5, and with crotononitrile afforded the pyridine 8. Compounds 9 and 11a-c were obtained by reaction of 1 with malo...Condensation of β-Oxoanilide 1 with active methylene derivatives 2a,bafforded the pyridine derivative 5, and with crotononitrile afforded the pyridine 8. Compounds 9 and 11a-c were obtained by reaction of 1 with malononitrile dimer and arylidinemalononitrile 10a-10c. In contrast, when compound 1 reacted with ethoxymethylen malononitrile afforded the pyridine derivative 13. On the other hand, treatment of 1 with anthranilic acid gave the quinoline derivative 14. Also, reactions of 1 with isothiocyanate derivatives afforded compounds 16-18. The reaction of 1 with chalcone derivative afforded the pyridine derivative 22. Treatment of compound 1 with thiourea produced pyrimidine derivative 23. Furthermore, compound 1 converted into pyrimidinethione 24a and pyrimidinone 24b on treatment with a mixture of aromatic aldehydes and thiourea or urea respectively. Reaction of 24a with hydrazonyl halide, thiosemicarbazide and arylidinecyanothioacetamide afforded compounds 26, 28 and 29. Compound 29 was treated with chloroacetonitrile to afford compound 30. Six compounds from the newly synthesized were screened for antibacterial and antifungal activity against bacteria staphylococcus aureus, bacillus cereus and klebsiella pneumonia and fungi aspergillus flavus and aspergillus ochraceous, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, 1H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.展开更多
A series of novel 2-amino-4H-pyran derivatives have been synthesized via a three-component reaction of α,β-unsaturated ketone derivatives, malononitrile, aldehydes in excellent yields, using DBU as a catalyst and et...A series of novel 2-amino-4H-pyran derivatives have been synthesized via a three-component reaction of α,β-unsaturated ketone derivatives, malononitrile, aldehydes in excellent yields, using DBU as a catalyst and ethanol as a cheap, safe, and environmentally benign solvent under mild conditions. Their antitumor activity was evaluated in three human tumor cell lines, including human colon cancer （HCT116）, human cervical cancer （Hela）. and non-small cell lung cancer （H1975）.展开更多
CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized b...CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.展开更多
ABSTRACT Ethyl 3,9-dimethyl-7-phenyl-6It-dibenzo[b,d]pyran-6-one-8-carboxylate （C24H20O4, Mr = 372.40） has been synthesized and its structure was determined by ^1H and ^1C NMR, ESI-MS, elemental analysis, and X-ray ...ABSTRACT Ethyl 3,9-dimethyl-7-phenyl-6It-dibenzo[b,d]pyran-6-one-8-carboxylate （C24H20O4, Mr = 372.40） has been synthesized and its structure was determined by ^1H and ^1C NMR, ESI-MS, elemental analysis, and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n, with a = 8.3674（11）, b = 10.6683（14）, c = 11.3817（15） A, a = 95.596（2）, β = 109.866（2）, γ = 94.495（2）°, V= 944.2（2）A^3, Z= 2, Dc = 1.310 g/cm3, μ= 0.089 mm^-1, F（000） = 392, R = 0.0482 and wR = 0.1281 for 2916 observed reflections with I 〉 2σ（I）. In the crystal structure, the fused tricyclic nucleus of the title compound is not fully coplanar. Analysis of the crystal packing indicates aromatic π-π stacking interactions occurring between the fused tricyclic aromatic rings of neighboring molecules in which a maximum overlap of the x-electron systems was achieved. Fluorescence and thermal studies indicate that compound 3 has good optical properties and thermal stability.展开更多
Ethyl 3,9-dihydroxy-9-methyl-7-phenyl-7,8,10-trihydro-6H-dibenzo[b,d]pyran-6-one-8-carboxylate（C（23）H（22）O6,Mr = 394.42） has been synthesized and its structure was determined by ~1H and ^（13）C NMR,ESI-MS,eleme...Ethyl 3,9-dihydroxy-9-methyl-7-phenyl-7,8,10-trihydro-6H-dibenzo[b,d]pyran-6-one-8-carboxylate（C（23）H（22）O6,Mr = 394.42） has been synthesized and its structure was determined by ~1H and ^（13）C NMR,ESI-MS,elemental analysis,and X-ray single-crystal diffraction.The crystal belongs to the triclinic system,space group P1,with a = 8.8220（17）,b = 9.881（2）,c = 12.157（2） A,α= 90.488（3）,β= 102.664（4）,γ= 98.799（3）°,V= 1020.8（3） A^3,Z= 2,Dc = 1.342 g/cm^3,μ= 0.099mm^（-1）,F（000） = 436,R = 0.0615 and wR = 0.2501 for 2592 observed reflections with（I2σ（I））.In the crystal structure,the coumarin ring system is planar and the 3：4 fused cyclohexane ring adopts distorted half-chair conformation.Rich hydrogen bonding interactions are formed between compound 2 and lattice water molecules.These interactions assemble molecules of 2 into 2D layered networks in an AB stacking sequence.Its in vitro antiproliferative activities against three human cancer cell lines were evaluated by MTT assay.展开更多
A rapid, one-pot and highly efficient protocol for the synthesis of pharmaceutically interesting functionalized 2-amino-3-cyano-4H-pyran and spirooxindole derivatives has been developed using commercially available Cs...A rapid, one-pot and highly efficient protocol for the synthesis of pharmaceutically interesting functionalized 2-amino-3-cyano-4H-pyran and spirooxindole derivatives has been developed using commercially available Cs F as a catalyst in the reaction of malononitrile and aryl aldehydes or isatins with 1,3-cyclohexanediones. The major advantages of this methodology are excellent yield at ambient temperature, very short reaction time（5–10 min）, and use of an inexpensive catalyst.展开更多
Novel fluorescent coumarin-4H-pyran conjugates were achieved by three-component reactions of various synthetic β-ketoesters with aldehydes and malononitrile in aqueous media.Besides mild reaction conditions,operation...Novel fluorescent coumarin-4H-pyran conjugates were achieved by three-component reactions of various synthetic β-ketoesters with aldehydes and malononitrile in aqueous media.Besides mild reaction conditions,operational simplicity,absence of tedious separation procedures,using of inexpensive and nontoxic commercially available cationic surfactant cetyltrimethylammonium chloride（CTAC） as a catalyst are the prominent advantage of this method.展开更多
A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl ac...A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin （II） chloride as a catalyst. In this method SnCl2/nano Si02 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.展开更多
Neopeapyran（1）,an unusual furo[2,3b]pyran analogue,together with a new cyclopeptide,turnagainolide C（2）,were isolated from Streptomyces sp.S2236 associated with the rhizosphere soil of Panax notoginseng.The planar...Neopeapyran（1）,an unusual furo[2,3b]pyran analogue,together with a new cyclopeptide,turnagainolide C（2）,were isolated from Streptomyces sp.S2236 associated with the rhizosphere soil of Panax notoginseng.The planar structure and relative configuration of neopeapyran（1） were elucidated on the basis of spectroscopic techniques,while the absolute configuration was determined by TDDFT calculation.The absolute configuration of turnagainolide C（2） was determined by partial hydrolysis,together with the advanced Marfey’s method and spectroscopic analysis.The antimicrobial activities of these two compounds were also investigated.展开更多
The title compounds have been synthesized via a three-component reaction and their structures were characterized by IR, ^1H NMR, ^13C NMR and X-ray single-crystal diffraction. The crystal of compound 4a belongs to mon...The title compounds have been synthesized via a three-component reaction and their structures were characterized by IR, ^1H NMR, ^13C NMR and X-ray single-crystal diffraction. The crystal of compound 4a belongs to monoclinic, space group P121/c1 with a = 8.575（3）, b = 9.590（3）, c = 21.431（6）A, β = 91.172（3）°, V = 1762.1（9）A^3, Mr = 393.36, Z = 4, Dc= 1.483 g/cm^3, μ（MoKα） = 0.113 mm^-1, F（000） = 816, the final R = 0.0366 and wR = 0.0941. The crystal of compound 4b is of triclinic, space group P-1 with a = 8.6420（17）, b = 9.761（2）, c = 11.132（2） A, α = 97.51（3）, β = 97.86（3）, γ = 92.85（3）°, V = 920.1（3） A^3, Mr = 393.36, Z = 2, Dc = 1.420 g/cm^3, μ（MoKα） = 0.108 mm^-1, F（000） = 408, the final R = 0.0612 and wR = 0.1781. In each molecular structure, the naphthalene rings and pyran rings are almost coplanar with the latter in an envelope conformation. The rings formed by the N-H…O intramolecular hydrogen bonds are almost planar in these compounds. Their crystal packing is stabilized by intermolecular hydrogen bonds together with C-H…π and π-π stacking interactions.展开更多
The electronic transport properties of a naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's function formalism combined with first-principles density functional theory...The electronic transport properties of a naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's function formalism combined with first-principles density functional theory.The molecule that comprises the switch can convert between its open and closed forms upon photoexcitation.Theoretical results show that the current through the open form is significantly larger than that through the closed form,which is different from other optical switches based on ring-opening reactions of the molecular bridge.The maximum on-off ratio(about 90)can be obtained at 1.4 V.The physical origin of the switching behavior is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap.Our result shows that the naphthopyran-based molecule is a good candidate for optical molecular switches and will be useful in the near future.展开更多
Current synthesis of α-substituted 3,6-dihydro-2H-pyrans dominantly relies on functional group transformation. Herein, a direct and practical oxidative C -H alkynylation and alkenylation of 3,6-dihydro-2H-pyran skele...Current synthesis of α-substituted 3,6-dihydro-2H-pyrans dominantly relies on functional group transformation. Herein, a direct and practical oxidative C -H alkynylation and alkenylation of 3,6-dihydro-2H-pyran skeletons with a range of potassium trifluoroborates is developed. The metal-free process is well tolerated with a wide variety of 3,6-dihydro-2H-pyrans, rapidly providing a library of 2,4-disubstituted 3,6-dihydro-2H-pyrans with diverse patterns of α-functionalities for further diversification and bioactive small molecule identification.展开更多
A series of tetrahydrobenzo-[b]-pyran derivative was synthesized by the reaction of arylmethylene malononitrile or arylmethylene cyanoacetate with dimedone in ethylene glycol at 80C without catalyst. The structures o...A series of tetrahydrobenzo-[b]-pyran derivative was synthesized by the reaction of arylmethylene malononitrile or arylmethylene cyanoacetate with dimedone in ethylene glycol at 80C without catalyst. The structures of the two products were characterized by X-ray diffraction.展开更多
基金the National Natural Science Foundation of China(No.20772025)the Program for Science & Technology Innovation Talents in Universities of Henan Province(No.2008HASTIT006)the Natural Science Foundation of Department of Education of Henan Province(No.2008A150013).
文摘Promoted and mediated by an ionic liquid-[bmim][BF4], fused pyrans or arylbis（4-hydroxy-6-methyl-2-oxo-2H-pyran-3- yl）methanes were efficiently and selectively prepared from the reaction of aldehyde and 4-hydroxy-6-methyl-2-oxo-pyran with or without acetic anhydride. By using these novel procedures, pyrimidine nucleoside-fused pyran and arylbis（pyranon-3-yl）methane hybrids with potential biological activities were constructed.
文摘A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and malononitrile in water using H6P2W18O62á18H2O as catalyst.Reusability of the catalyst and reaction media,short reaction times and easy isolation of products are some added advantages of the present methodology.
文摘4-（Succinimido）-1-butane sulfonic acid as an efficient and reusable Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives under solvent-free conditions.The catalyst can be prepared by mixing succinimide and 1,4-butanesultone that is more simple and safer than the preparation of succinimide sulfonic acid.This method has the advantages of high yield,clean reaction,simple methodology and short reaction time.The catalyst could be recycled without significant loss of activity.
文摘A ligand free, Palladium nanoparticles catalyzed synthesis of pyran derivatives using C-H activated compound, malononitrile and aryl aldehyde via Knoevenagel condensation followed by Michael addition reaction using Palladium nanoparticles as catalyst in one-pot is described herein. The advantages of this method lie in its simplicity, low catalyst loading, cost effectiveness and easy to handle. The Palladium Nanoparticles can be reused without loss of activity even after recycling four times. The palladium nanoparticles were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM). The present method also allows us to synthesize highly functionalized title compounds from simple and readily available inputs.
文摘Diammonium hydrogen phosphate and potassium carbonate-catalyzed one-pot synthesis of 1,4- phenylene-bis（2-amino-4H-pyran-3-carbonitrile and 2-amino-4-aryl-4H-pyran-3-carbonitrile deriva- tives has been achieved by a three-component cyclocondensation of aldehydes, malononitrile, and different nucleophiles in aqueous medium in high yields.
基金This work was financially supported by the National Natural Science Foundation of China(No.20372018)the Science Foundation of Henan Normal University for Young Scholars(No.0307032).
文摘A rapid and facile preparation of benzo-[b]-pyran derivatives through condensation of chalcone and 5, 5-dimethyl-1,3-cyclohexandione under microwave irradiation in the presence of catalytic amount of InCl3·4H2O has been developed. With its high efficiency, operational simplicity and environmental benignancy, this method may provide a useful alternative for the preparation of benzo-[b]-pyran derivatives.
文摘A series of novel pleuromutilin derivatives with 4H-pyran-4-one and pyridin-4-one substitution in the C-14 side chain have been designed and synthesized. In vitro antibacterial activity evaluation showed that most of the derivatives exhibited potent antibacterial activity against drug resistant Gram-positive strains. Compounds 12 a, 12 d, and 28 are the most active derivatives in this series, displaying activity comparable to that of retapamulin and BC-3781. As the metabolic stability of this series is not satisfactory, further modifications are going on to improve their pharmacokinetic profile.
文摘Condensation of β-Oxoanilide 1 with active methylene derivatives 2a,bafforded the pyridine derivative 5, and with crotononitrile afforded the pyridine 8. Compounds 9 and 11a-c were obtained by reaction of 1 with malononitrile dimer and arylidinemalononitrile 10a-10c. In contrast, when compound 1 reacted with ethoxymethylen malononitrile afforded the pyridine derivative 13. On the other hand, treatment of 1 with anthranilic acid gave the quinoline derivative 14. Also, reactions of 1 with isothiocyanate derivatives afforded compounds 16-18. The reaction of 1 with chalcone derivative afforded the pyridine derivative 22. Treatment of compound 1 with thiourea produced pyrimidine derivative 23. Furthermore, compound 1 converted into pyrimidinethione 24a and pyrimidinone 24b on treatment with a mixture of aromatic aldehydes and thiourea or urea respectively. Reaction of 24a with hydrazonyl halide, thiosemicarbazide and arylidinecyanothioacetamide afforded compounds 26, 28 and 29. Compound 29 was treated with chloroacetonitrile to afford compound 30. Six compounds from the newly synthesized were screened for antibacterial and antifungal activity against bacteria staphylococcus aureus, bacillus cereus and klebsiella pneumonia and fungi aspergillus flavus and aspergillus ochraceous, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, 1H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.
文摘A series of novel 2-amino-4H-pyran derivatives have been synthesized via a three-component reaction of α,β-unsaturated ketone derivatives, malononitrile, aldehydes in excellent yields, using DBU as a catalyst and ethanol as a cheap, safe, and environmentally benign solvent under mild conditions. Their antitumor activity was evaluated in three human tumor cell lines, including human colon cancer （HCT116）, human cervical cancer （Hela）. and non-small cell lung cancer （H1975）.
基金the Behbahan Khatam Alanbia University of Technology for the partial support of this work
文摘CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.
基金supported by grants from the Provincial Key Project of Natural Science Research for Colleges and Universities of Anhui Province(No.20130911160)the Doctoral Foundation of Anhui University of Science and Technology(No.11117)
文摘ABSTRACT Ethyl 3,9-dimethyl-7-phenyl-6It-dibenzo[b,d]pyran-6-one-8-carboxylate （C24H20O4, Mr = 372.40） has been synthesized and its structure was determined by ^1H and ^1C NMR, ESI-MS, elemental analysis, and X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P21/n, with a = 8.3674（11）, b = 10.6683（14）, c = 11.3817（15） A, a = 95.596（2）, β = 109.866（2）, γ = 94.495（2）°, V= 944.2（2）A^3, Z= 2, Dc = 1.310 g/cm3, μ= 0.089 mm^-1, F（000） = 392, R = 0.0482 and wR = 0.1281 for 2916 observed reflections with I 〉 2σ（I）. In the crystal structure, the fused tricyclic nucleus of the title compound is not fully coplanar. Analysis of the crystal packing indicates aromatic π-π stacking interactions occurring between the fused tricyclic aromatic rings of neighboring molecules in which a maximum overlap of the x-electron systems was achieved. Fluorescence and thermal studies indicate that compound 3 has good optical properties and thermal stability.
基金the financial support from the Natural Science Foundation of Jiangsu University of Technologythe Provincial Key Project of Natural Science Research for Colleges and Universities of Anhui Province(KJ2014A062)
文摘Ethyl 3,9-dihydroxy-9-methyl-7-phenyl-7,8,10-trihydro-6H-dibenzo[b,d]pyran-6-one-8-carboxylate（C（23）H（22）O6,Mr = 394.42） has been synthesized and its structure was determined by ~1H and ^（13）C NMR,ESI-MS,elemental analysis,and X-ray single-crystal diffraction.The crystal belongs to the triclinic system,space group P1,with a = 8.8220（17）,b = 9.881（2）,c = 12.157（2） A,α= 90.488（3）,β= 102.664（4）,γ= 98.799（3）°,V= 1020.8（3） A^3,Z= 2,Dc = 1.342 g/cm^3,μ= 0.099mm^（-1）,F（000） = 436,R = 0.0615 and wR = 0.2501 for 2592 observed reflections with（I2σ（I））.In the crystal structure,the coumarin ring system is planar and the 3：4 fused cyclohexane ring adopts distorted half-chair conformation.Rich hydrogen bonding interactions are formed between compound 2 and lattice water molecules.These interactions assemble molecules of 2 into 2D layered networks in an AB stacking sequence.Its in vitro antiproliferative activities against three human cancer cell lines were evaluated by MTT assay.
基金SAIF Panjab University for providing analytical facilities for characterization of compounds
文摘A rapid, one-pot and highly efficient protocol for the synthesis of pharmaceutically interesting functionalized 2-amino-3-cyano-4H-pyran and spirooxindole derivatives has been developed using commercially available Cs F as a catalyst in the reaction of malononitrile and aryl aldehydes or isatins with 1,3-cyclohexanediones. The major advantages of this methodology are excellent yield at ambient temperature, very short reaction time（5–10 min）, and use of an inexpensive catalyst.
基金the financial support from the National Natural Science Foundation of China(No.21462041)Natural-Science Foundation for Distinguished Young Scholars of Xinjiang Uyghur Autonomous Region(No.Qn2015jq002)the Tianshan Talent Cultivation Project of Xinjiang Uyghur Autonomous Region
文摘Novel fluorescent coumarin-4H-pyran conjugates were achieved by three-component reactions of various synthetic β-ketoesters with aldehydes and malononitrile in aqueous media.Besides mild reaction conditions,operational simplicity,absence of tedious separation procedures,using of inexpensive and nontoxic commercially available cationic surfactant cetyltrimethylammonium chloride（CTAC） as a catalyst are the prominent advantage of this method.
基金University of Kashan for supporting this work by Grant No.159196/XV
文摘A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin （II） chloride as a catalyst. In this method SnCl2/nano Si02 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.
基金funded by grants from the National Natural Science Foundation of China (Nos. 81360480, 81460536 and 81560571)
文摘Neopeapyran（1）,an unusual furo[2,3b]pyran analogue,together with a new cyclopeptide,turnagainolide C（2）,were isolated from Streptomyces sp.S2236 associated with the rhizosphere soil of Panax notoginseng.The planar structure and relative configuration of neopeapyran（1） were elucidated on the basis of spectroscopic techniques,while the absolute configuration was determined by TDDFT calculation.The absolute configuration of turnagainolide C（2） was determined by partial hydrolysis,together with the advanced Marfey’s method and spectroscopic analysis.The antimicrobial activities of these two compounds were also investigated.
基金supported by the National Natural Science Foundation of China (No. 20672090)Natural Science Foundation of Jiangsu Province (No. BK2006033)Six Kinds of Professional Elite Foundation of Jiangsu Province (No. 06-A-039)
文摘The title compounds have been synthesized via a three-component reaction and their structures were characterized by IR, ^1H NMR, ^13C NMR and X-ray single-crystal diffraction. The crystal of compound 4a belongs to monoclinic, space group P121/c1 with a = 8.575（3）, b = 9.590（3）, c = 21.431（6）A, β = 91.172（3）°, V = 1762.1（9）A^3, Mr = 393.36, Z = 4, Dc= 1.483 g/cm^3, μ（MoKα） = 0.113 mm^-1, F（000） = 816, the final R = 0.0366 and wR = 0.0941. The crystal of compound 4b is of triclinic, space group P-1 with a = 8.6420（17）, b = 9.761（2）, c = 11.132（2） A, α = 97.51（3）, β = 97.86（3）, γ = 92.85（3）°, V = 920.1（3） A^3, Mr = 393.36, Z = 2, Dc = 1.420 g/cm^3, μ（MoKα） = 0.108 mm^-1, F（000） = 408, the final R = 0.0612 and wR = 0.1781. In each molecular structure, the naphthalene rings and pyran rings are almost coplanar with the latter in an envelope conformation. The rings formed by the N-H…O intramolecular hydrogen bonds are almost planar in these compounds. Their crystal packing is stabilized by intermolecular hydrogen bonds together with C-H…π and π-π stacking interactions.
基金by the National Natural Science Foundation of China under Grant Nos 11004156 and 11074146the National Basic Research Program of China under Grant No 2009CB929204the Scientific Research Program Funded by Shaanxi Provincial Education Department(Nos 09JK461 and 11JK0521).
文摘The electronic transport properties of a naphthopyran-based molecular optical switch are investigated by using the nonequilibrium Green's function formalism combined with first-principles density functional theory.The molecule that comprises the switch can convert between its open and closed forms upon photoexcitation.Theoretical results show that the current through the open form is significantly larger than that through the closed form,which is different from other optical switches based on ring-opening reactions of the molecular bridge.The maximum on-off ratio(about 90)can be obtained at 1.4 V.The physical origin of the switching behavior is interpreted based on the spatial distributions of molecular orbitals and the HOMO-LUMO gap.Our result shows that the naphthopyran-based molecule is a good candidate for optical molecular switches and will be useful in the near future.
基金financial supported by the National Natural Science Foundation of China (No. 21722204)Fok Ying Tung Education Foundation (No. 151035)+1 种基金the Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University) (No. CHEMR2016-B09)Guangxi Funds for Distinguished expert
文摘Current synthesis of α-substituted 3,6-dihydro-2H-pyrans dominantly relies on functional group transformation. Herein, a direct and practical oxidative C -H alkynylation and alkenylation of 3,6-dihydro-2H-pyran skeletons with a range of potassium trifluoroborates is developed. The metal-free process is well tolerated with a wide variety of 3,6-dihydro-2H-pyrans, rapidly providing a library of 2,4-disubstituted 3,6-dihydro-2H-pyrans with diverse patterns of α-functionalities for further diversification and bioactive small molecule identification.
文摘A series of tetrahydrobenzo-[b]-pyran derivative was synthesized by the reaction of arylmethylene malononitrile or arylmethylene cyanoacetate with dimedone in ethylene glycol at 80C without catalyst. The structures of the two products were characterized by X-ray diffraction.
