Acid dissociation constants, pKa, of 2-pyrrolaldehyde phenylsulphonyl hydrazone, 1, and 2-thiophenealdehyde phenylsulphonyl hydrazone, 2, have been determined spectrophotometrically in ethanol-water media of various c...Acid dissociation constants, pKa, of 2-pyrrolaldehyde phenylsulphonyl hydrazone, 1, and 2-thiophenealdehyde phenylsulphonyl hydrazone, 2, have been determined spectrophotometrically in ethanol-water media of various compositions over the temperature range 25℃ - 45℃. The obtained results were used in the calculation of the enthalpy, △H°, and the entropy, △S°, of the ionization processes. The slight variations observed in the pKa values of the thiophene compound compared to the pyrrol analogue revealed that neither of the two hetero atoms in the pyrrol or thiophene rings, of the two compounds, is involved in a hydrogen bond chelation. This conclusion was also confirmed through measurements of the dipole moment, IR and NMR spectra.展开更多
6-（2,5-Dimethyl-1H-pyrrol-1-yl）pyridin-2-amine （1） was synthesized and characte-rized by elemental analyses,1H-NMR and 13C-NMR,FTIR,Uv-Vis,mass spectral studies and single-crystal X-ray diffraction.All data obtain...6-（2,5-Dimethyl-1H-pyrrol-1-yl）pyridin-2-amine （1） was synthesized and characte-rized by elemental analyses,1H-NMR and 13C-NMR,FTIR,Uv-Vis,mass spectral studies and single-crystal X-ray diffraction.All data obtained from spectral studies support the structural properties of 1.Intermolecular N-H…N hydrogen bonds produce an R22（8） ring.An extensive three-dimensional network formed by C-H…π and N-H…π-facial hydrogen bonds is responsible for the crystal stabilization.The combination of C-H…π interactions produces R33（12）,R43（19） and R44（20） rings.展开更多
A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a hi...A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.展开更多
A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction i...A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction in one pot was developed.The three-component cascade reaction was enabled by refluxing a mixture of the substrates in 1,4-dioxane in the presence of Ag_(2)CO_(3) as a Lewis acid promoter.As a result,a series of functionalized pyrroles(OPCMs,3),was prepared regioselectively and in high yields(80%-88%)through the formation of three bonds.This protocol can be used in the synthesis of OPCMs rather than through conventional,multi-step reactions and is suitable for both combinatorial and parallel syntheses of pyrroles.展开更多
3,3＇-Bis（5-（N-（4-hydroxylphenyl）imidomethyl）pyrrol-2-yl）pentane 1 has been synthesized and characterized. The crystal of its methanol complex, 1·（CH3OH）2, belongs to the orthorhombic system, space group ...3,3＇-Bis（5-（N-（4-hydroxylphenyl）imidomethyl）pyrrol-2-yl）pentane 1 has been synthesized and characterized. The crystal of its methanol complex, 1·（CH3OH）2, belongs to the orthorhombic system, space group Pccn with a = 18.094（2）, b = 11.6890（16）, c = 13.3629（19） , V = 2826.3（7） 3, Z = 8, C14.5H18N2O2, Mr = 252.31, Dc = 1.186 g/cm3, F（000） = 1080 and μ（MoKα） = 0.080 mm-1. The final R = 0.0662 and wR = 0.1801 for 1908 observed reflections with I 2σ（I）, and R = 0.0800 and wR = 0.1948 for all reflections. In the solid state, bridged by included methanol molecules, the molecules of compound 1 form interpenetrated grid structure through N–H···O and O–H···O hydrogen bonds.展开更多
Hydrilla verticillata （Linn. f.） Royle is a submerged plant for phytoremediation on Taihu Lake, China. The planted submerged plant should be harvested in every autumn to reduce the nutrition burden of the lake. Five...Hydrilla verticillata （Linn. f.） Royle is a submerged plant for phytoremediation on Taihu Lake, China. The planted submerged plant should be harvested in every autumn to reduce the nutrition burden of the lake. Five compounds were firstly isolated by column chromatography and purified from the extractions of Hydrilla verticillata （Linn. f.） Royle. 1-（5＇-Hydroxy-4＇-hydroxymethyl-1＇-methyl-1H-pyrrol-2＇-yl）-henicosa-2,12,15-trien-1-one （2） and thymidine （3） were identified by EIMS, 1H NMR, laC NMR and IR spectra. Crystal loliolide （1） and sulfur-gamma （4） were identified by X-ray diffraction. Octadecanedioic acid （5） was also elucidated. Among them, compound 2 is a new natural compound, loliolide （1） and thymidine （3） are known bioactive substances. The results provided basic research data for exploring their application as medical materials.展开更多
A simple and eco-friendly method for the preparation of 1,5-diaryl-3-（arylamino）-lH-pyrrol-2（5H）-ones via the cyclo-condensation reaction of aldehydes, amines and ethyl pyruvate in the presence of silica supported...A simple and eco-friendly method for the preparation of 1,5-diaryl-3-（arylamino）-lH-pyrrol-2（5H）-ones via the cyclo-condensation reaction of aldehydes, amines and ethyl pyruvate in the presence of silica supported ferric chlo- ride （SiO2-FeCl3） as reusable heterogeneous catalyst is described. The present methodology offers several advantages such as excellent yields, simple procedure and short reaction times.展开更多
The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray d...The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.展开更多
文摘Acid dissociation constants, pKa, of 2-pyrrolaldehyde phenylsulphonyl hydrazone, 1, and 2-thiophenealdehyde phenylsulphonyl hydrazone, 2, have been determined spectrophotometrically in ethanol-water media of various compositions over the temperature range 25℃ - 45℃. The obtained results were used in the calculation of the enthalpy, △H°, and the entropy, △S°, of the ionization processes. The slight variations observed in the pKa values of the thiophene compound compared to the pyrrol analogue revealed that neither of the two hetero atoms in the pyrrol or thiophene rings, of the two compounds, is involved in a hydrogen bond chelation. This conclusion was also confirmed through measurements of the dipole moment, IR and NMR spectra.
基金supported by Karadeniz Technical University Research Fund (No. 2005.111.02.2)the Faculty of Arts and Sciences,Ondokuz Mayis University,Turkey,for the use of the Stoe IPDS-II diffractometer (purchased under grant No. F279 of the University Research Fund)
文摘6-（2,5-Dimethyl-1H-pyrrol-1-yl）pyridin-2-amine （1） was synthesized and characte-rized by elemental analyses,1H-NMR and 13C-NMR,FTIR,Uv-Vis,mass spectral studies and single-crystal X-ray diffraction.All data obtained from spectral studies support the structural properties of 1.Intermolecular N-H…N hydrogen bonds produce an R22（8） ring.An extensive three-dimensional network formed by C-H…π and N-H…π-facial hydrogen bonds is responsible for the crystal stabilization.The combination of C-H…π interactions produces R33（12）,R43（19） and R44（20） rings.
文摘A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.
基金the Natural Science Foundation of Yunnan Province(No.2019FY003003)the National Natural Science Foundation of China(No.21662042)the Scientific and Technological Innovation Team of Green Synthesis and Activity Research of Natural-like Heterocyclic Compound Libraries in Universities of Yunnan Province(No.C17624011121).
文摘A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction in one pot was developed.The three-component cascade reaction was enabled by refluxing a mixture of the substrates in 1,4-dioxane in the presence of Ag_(2)CO_(3) as a Lewis acid promoter.As a result,a series of functionalized pyrroles(OPCMs,3),was prepared regioselectively and in high yields(80%-88%)through the formation of three bonds.This protocol can be used in the synthesis of OPCMs rather than through conventional,multi-step reactions and is suitable for both combinatorial and parallel syntheses of pyrroles.
基金supported by the National Natural Science Foundation of China (No. 20702038)
文摘3,3＇-Bis（5-（N-（4-hydroxylphenyl）imidomethyl）pyrrol-2-yl）pentane 1 has been synthesized and characterized. The crystal of its methanol complex, 1·（CH3OH）2, belongs to the orthorhombic system, space group Pccn with a = 18.094（2）, b = 11.6890（16）, c = 13.3629（19） , V = 2826.3（7） 3, Z = 8, C14.5H18N2O2, Mr = 252.31, Dc = 1.186 g/cm3, F（000） = 1080 and μ（MoKα） = 0.080 mm-1. The final R = 0.0662 and wR = 0.1801 for 1908 observed reflections with I 2σ（I）, and R = 0.0800 and wR = 0.1948 for all reflections. In the solid state, bridged by included methanol molecules, the molecules of compound 1 form interpenetrated grid structure through N–H···O and O–H···O hydrogen bonds.
文摘Hydrilla verticillata （Linn. f.） Royle is a submerged plant for phytoremediation on Taihu Lake, China. The planted submerged plant should be harvested in every autumn to reduce the nutrition burden of the lake. Five compounds were firstly isolated by column chromatography and purified from the extractions of Hydrilla verticillata （Linn. f.） Royle. 1-（5＇-Hydroxy-4＇-hydroxymethyl-1＇-methyl-1H-pyrrol-2＇-yl）-henicosa-2,12,15-trien-1-one （2） and thymidine （3） were identified by EIMS, 1H NMR, laC NMR and IR spectra. Crystal loliolide （1） and sulfur-gamma （4） were identified by X-ray diffraction. Octadecanedioic acid （5） was also elucidated. Among them, compound 2 is a new natural compound, loliolide （1） and thymidine （3） are known bioactive substances. The results provided basic research data for exploring their application as medical materials.
文摘A simple and eco-friendly method for the preparation of 1,5-diaryl-3-（arylamino）-lH-pyrrol-2（5H）-ones via the cyclo-condensation reaction of aldehydes, amines and ethyl pyruvate in the presence of silica supported ferric chlo- ride （SiO2-FeCl3） as reusable heterogeneous catalyst is described. The present methodology offers several advantages such as excellent yields, simple procedure and short reaction times.
基金This work was supported by the National Natural Science Foundation of China (No. 20472072 and 20332060)the CAS Academician Foundation of Zhejiang Province
文摘The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.
