The title compound 1 was synthesized from 1.2:5,6-dianhydro-3,4-dianhydro-3,4-isopropylideneD-mannitol 2 through four steps in a total yield of 53%. The absolute configuration of this compound was confirmed by X-ray d...The title compound 1 was synthesized from 1.2:5,6-dianhydro-3,4-dianhydro-3,4-isopropylideneD-mannitol 2 through four steps in a total yield of 53%. The absolute configuration of this compound was confirmed by X-ray diffraction.展开更多
A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H...A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H37Rv. No obvious antitubercular activities could be observed (MIC > 10 ug/mL). The results are in sharp contrast with the previously reported data.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
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
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
The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Harniltonian, the strengths of spin-orb...The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Harniltonian, the strengths of spin-orbit coupling were estimated, which plays an essential role in the spin transitions between different spin states. Calculated results show that phosphorescence and non-radiative decay via intersystem crossing to the So state are concurrent processes occurring at the T1 state. A rapid depletion of the S1 state via intersystem crossing to the T1 state can be mediated by the T2 state, if spin relaxation is fast within the triplet levels. Our calculated results are in close agreement with experimental observations.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
KF-Al2O3 as a recyclable basic catalyst for the three-component synthesis of 4H-pyran derivatives by the reaction of aldehydes, malononitrile and active methylene dicarbonyl compounds in ethanol at room temperature is...KF-Al2O3 as a recyclable basic catalyst for the three-component synthesis of 4H-pyran derivatives by the reaction of aldehydes, malononitrile and active methylene dicarbonyl compounds in ethanol at room temperature is described. The protocol is environmentally benign and offers rapid access to a wide array of 4H-pyran heterocycles in good to excellent yields.展开更多
Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneo...Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.展开更多
文摘The title compound 1 was synthesized from 1.2:5,6-dianhydro-3,4-dianhydro-3,4-isopropylideneD-mannitol 2 through four steps in a total yield of 53%. The absolute configuration of this compound was confirmed by X-ray diffraction.
文摘A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H37Rv. No obvious antitubercular activities could be observed (MIC > 10 ug/mL). The results are in sharp contrast with the previously reported data.
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）.
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.
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.
文摘The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Harniltonian, the strengths of spin-orbit coupling were estimated, which plays an essential role in the spin transitions between different spin states. Calculated results show that phosphorescence and non-radiative decay via intersystem crossing to the So state are concurrent processes occurring at the T1 state. A rapid depletion of the S1 state via intersystem crossing to the T1 state can be mediated by the T2 state, if spin relaxation is fast within the triplet levels. Our calculated results are in close agreement with experimental observations.
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.
文摘KF-Al2O3 as a recyclable basic catalyst for the three-component synthesis of 4H-pyran derivatives by the reaction of aldehydes, malononitrile and active methylene dicarbonyl compounds in ethanol at room temperature is described. The protocol is environmentally benign and offers rapid access to a wide array of 4H-pyran heterocycles in good to excellent yields.
文摘Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.
