Brnsted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen su...Brnsted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate, and triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, catalyzed efficient Pechmann condensation of phloroglucinol with β-keto ethyl/ methyl esters. 5,7-Dihydroxy-4-methylcoumarin and 5,7-dihydroxy-4-phenylcoumarin were prepared in good to excellent yields under mild, ambient, and solvent-free conditions. Pyrano[2,3-h] coumarins were then prepared by one-pot three-component reactions of 5,7-dihydroxy-4-subsituted coumarin, malononitrile, and aldehydes in the presence of catalytic amounts of Br nsted basic ionic liquids, namely 2-hydroxyethylammonium formate, 3-hydroxypropanaminium acetate, 1-butyl-3-methylimidazolium hydroxide, pyrrolidinium formate, and pyrrolidinium acetate, under thermal solvent-free conditions. The catalysts are environmentally benign and can be easily prepared, stored, and recovered without significant loss of activity.展开更多
Silica-grafted N-propyl-imidazolium hydrogen sulfate ([Sipim]HSO4) is employed as a recyclable heterogeneous ionic liquid catalyst for the synthesis of 3,4-dihydropyrano[c]-chromenes by the reaction of aromatic aldehy...Silica-grafted N-propyl-imidazolium hydrogen sulfate ([Sipim]HSO4) is employed as a recyclable heterogeneous ionic liquid catalyst for the synthesis of 3,4-dihydropyrano[c]-chromenes by the reaction of aromatic aldehydes, malononitrile and 4-hydroxycoumarin at 100°C under solvent-free conditions. Also, heterogeneous ionic liquid catalyst was used for the synthesis of pyrano[2,3-c]-pyrazoles by the reaction of aromatic aldehydes, malononitrile and 3-methyl-l-phenyl-5-pyrazolone at 110°C under solvent-free conditions. The heterogeneous ionic liquid showed much the same efficiency when used in consecutive reaction runs.展开更多
A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up ...A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up to 10-fold higher inhibition(IC5074.0±1.3μmol·L-1)than acarbose.The molecular docking revealed that compound 10 f could bind toα-glucosidase via the hydrophobic,π-πstacking,and hydrogen bonding interactions.The results may benefit further structural modifications to find new and potentα-glucosidase inhibitors.展开更多
The title compound 7-amino-2,3,4,5-tetrahydro-1,3-dimethyl-5-（2-nitrophenyl）- 2,4- dioxo-1H-pyrano[2,3-d] pyrirnidine-6-carbonitrile DMF solvate 1 （C19H20N6O6, Mr = 428.41） was synthesized and crystallized. The cr...The title compound 7-amino-2,3,4,5-tetrahydro-1,3-dimethyl-5-（2-nitrophenyl）- 2,4- dioxo-1H-pyrano[2,3-d] pyrirnidine-6-carbonitrile DMF solvate 1 （C19H20N6O6, Mr = 428.41） was synthesized and crystallized. The crystal belongs to the monoclinic system, space group P2 1/c with a = 11.383（2）, b = 13.372（2）, c = 13.673（2）A, β = 97.380（4）°, Z = 4, V = 2063.8（6）A^3, Dc = 1.379 g/cm^3,μ（MoKα） = 0.105 mm^-1, F（000） = 896, the final R = 0.0738 and wR = 0.1647 for 2964 observed reflections （I〉 2σ（I））. X-ray analysis reveals that the new pyran ring is coplanar, which is obviously different from those of other similar compounds. In addition, the unclassical hydrogen bonds of C-H…O and C-H…N are presented in the crystals except for the normal hydrogen bonds of N-H…O.展开更多
An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-a...An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-aza- 1,3-butadienes and aliphatic aldehydes tethered to an α,β-unsaturated ketone motif. A tandem O-Michael addition reaction was completed via acid catalysis.展开更多
吡喃并[2,3-c]吡唑类化合物作为一种极具前景和优势的结构单元,在医药和农业领域具有相当大的研究价值。本文在无溶剂条件下,以取代肼、取代醛、乙酰乙酸乙酯和丙二腈为原料,研究探讨反应时间、催化剂用量和温度对产率的影响,确定了最...吡喃并[2,3-c]吡唑类化合物作为一种极具前景和优势的结构单元,在医药和农业领域具有相当大的研究价值。本文在无溶剂条件下,以取代肼、取代醛、乙酰乙酸乙酯和丙二腈为原料,研究探讨反应时间、催化剂用量和温度对产率的影响,确定了最优反应条件,在此基础上,成功合成了一系列不同取代的吡喃并[2,3-c]吡唑化合物。在最优条件下,通过对不同时段的反应进行检测,推断出其发生的反应机理。目标化合物的结构经^(1)H-NMR、^(13)C-NMR和高分辨质谱仪(high resolution mass spectrometer,HRMS)确证。该方法所得目标化合物收率良好,操作简便,实用性强,具有潜在的工业化前景。展开更多
The use of biocatalysts is attracting an increasing amount of attention in chemical catalysis.Here,we have shown that bovine serum albumin（BSA）,a ubiquitous,inexpensive,non-enzymatic transport protein,can serve as a...The use of biocatalysts is attracting an increasing amount of attention in chemical catalysis.Here,we have shown that bovine serum albumin（BSA）,a ubiquitous,inexpensive,non-enzymatic transport protein,can serve as an efficient,retrievable catalyst in the one-pot four-component reaction of aryl aldehydes,malononitrile,hydrazine hydrate,and ethyl acetoacetate for the synthesis of pyrano[2,3-c]pyrazoles under mild reaction conditions.The BSA biocatalyst also displayed a high catalytic affinity for acyclic/cyclic ketones to yield the corresponding pyrano[2,3-c]pyrazoles or their spirocyclic variants.The BSA could be used for at least five cycles without serious loss of catalytic activity.This novel,efficient protocol has the merits of high yield,operational simplicity,and a relatively benign environmental impact.Moreover,the method extends the promiscuity of BSA as a biocatalyst.展开更多
基金the University of Sistan and Baluchestan Research Council for the partial support of this research
文摘Brnsted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate, and triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, catalyzed efficient Pechmann condensation of phloroglucinol with β-keto ethyl/ methyl esters. 5,7-Dihydroxy-4-methylcoumarin and 5,7-dihydroxy-4-phenylcoumarin were prepared in good to excellent yields under mild, ambient, and solvent-free conditions. Pyrano[2,3-h] coumarins were then prepared by one-pot three-component reactions of 5,7-dihydroxy-4-subsituted coumarin, malononitrile, and aldehydes in the presence of catalytic amounts of Br nsted basic ionic liquids, namely 2-hydroxyethylammonium formate, 3-hydroxypropanaminium acetate, 1-butyl-3-methylimidazolium hydroxide, pyrrolidinium formate, and pyrrolidinium acetate, under thermal solvent-free conditions. The catalysts are environmentally benign and can be easily prepared, stored, and recovered without significant loss of activity.
文摘Silica-grafted N-propyl-imidazolium hydrogen sulfate ([Sipim]HSO4) is employed as a recyclable heterogeneous ionic liquid catalyst for the synthesis of 3,4-dihydropyrano[c]-chromenes by the reaction of aromatic aldehydes, malononitrile and 4-hydroxycoumarin at 100°C under solvent-free conditions. Also, heterogeneous ionic liquid catalyst was used for the synthesis of pyrano[2,3-c]-pyrazoles by the reaction of aromatic aldehydes, malononitrile and 3-methyl-l-phenyl-5-pyrazolone at 110°C under solvent-free conditions. The heterogeneous ionic liquid showed much the same efficiency when used in consecutive reaction runs.
基金the National Key R&D Program of China(No.2018YF-A0507602)the National Natural Science Foundation of China(Nos.81821004 and21738001)。
文摘A series of novel pyrano[2,3-d]trizaole compounds were synthesized and theirα-glucosidase inhibitory activities were evaluated by in vitro enzyme assay.The experimental data demonstrated that compound 10 f showed up to 10-fold higher inhibition(IC5074.0±1.3μmol·L-1)than acarbose.The molecular docking revealed that compound 10 f could bind toα-glucosidase via the hydrophobic,π-πstacking,and hydrogen bonding interactions.The results may benefit further structural modifications to find new and potentα-glucosidase inhibitors.
基金the Foundation of the Youth (OH060099) of China University of Mining and Technologythe Foundation of Natural Science Foundation (06AXL010) of Xuzhou Normal UniversityNatural Science Foundation (04KJB150139) of Education Committee of Jiangsu Province
文摘The title compound 7-amino-2,3,4,5-tetrahydro-1,3-dimethyl-5-（2-nitrophenyl）- 2,4- dioxo-1H-pyrano[2,3-d] pyrirnidine-6-carbonitrile DMF solvate 1 （C19H20N6O6, Mr = 428.41） was synthesized and crystallized. The crystal belongs to the monoclinic system, space group P2 1/c with a = 11.383（2）, b = 13.372（2）, c = 13.673（2）A, β = 97.380（4）°, Z = 4, V = 2063.8（6）A^3, Dc = 1.379 g/cm^3,μ（MoKα） = 0.105 mm^-1, F（000） = 896, the final R = 0.0738 and wR = 0.1647 for 2964 observed reflections （I〉 2σ（I））. X-ray analysis reveals that the new pyran ring is coplanar, which is obviously different from those of other similar compounds. In addition, the unclassical hydrogen bonds of C-H…O and C-H…N are presented in the crystals except for the normal hydrogen bonds of N-H…O.
文摘An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-aza- 1,3-butadienes and aliphatic aldehydes tethered to an α,β-unsaturated ketone motif. A tandem O-Michael addition reaction was completed via acid catalysis.
文摘吡喃并[2,3-c]吡唑类化合物作为一种极具前景和优势的结构单元,在医药和农业领域具有相当大的研究价值。本文在无溶剂条件下,以取代肼、取代醛、乙酰乙酸乙酯和丙二腈为原料,研究探讨反应时间、催化剂用量和温度对产率的影响,确定了最优反应条件,在此基础上,成功合成了一系列不同取代的吡喃并[2,3-c]吡唑化合物。在最优条件下,通过对不同时段的反应进行检测,推断出其发生的反应机理。目标化合物的结构经^(1)H-NMR、^(13)C-NMR和高分辨质谱仪(high resolution mass spectrometer,HRMS)确证。该方法所得目标化合物收率良好,操作简便,实用性强,具有潜在的工业化前景。
基金supported by the National Natural Science Foundation of China(21372099,21072077)the the Natural Science Foundation of Guangdong Province(10151063201000051,8151063201000016)~~
文摘The use of biocatalysts is attracting an increasing amount of attention in chemical catalysis.Here,we have shown that bovine serum albumin（BSA）,a ubiquitous,inexpensive,non-enzymatic transport protein,can serve as an efficient,retrievable catalyst in the one-pot four-component reaction of aryl aldehydes,malononitrile,hydrazine hydrate,and ethyl acetoacetate for the synthesis of pyrano[2,3-c]pyrazoles under mild reaction conditions.The BSA biocatalyst also displayed a high catalytic affinity for acyclic/cyclic ketones to yield the corresponding pyrano[2,3-c]pyrazoles or their spirocyclic variants.The BSA could be used for at least five cycles without serious loss of catalytic activity.This novel,efficient protocol has the merits of high yield,operational simplicity,and a relatively benign environmental impact.Moreover,the method extends the promiscuity of BSA as a biocatalyst.
