In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antib...In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity.The results of antibacterial activities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity,and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues 7a and 7b.展开更多
A simple and efficient procedure for the synthesis of substituted benzothiazoles through condensation of 2-aminothiophenol with aromatic aldehydes in the presence of H2O2/HCl system in ethanol at room temperature is d...A simple and efficient procedure for the synthesis of substituted benzothiazoles through condensation of 2-aminothiophenol with aromatic aldehydes in the presence of H2O2/HCl system in ethanol at room temperature is described. The target compounds have been characterized by ^1H NMR, ^13C NMR, IR and MS. Short reaction time, easy and quick isolation of the products, and excellent yields are the main advantages of this procedure.展开更多
Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that ra...Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.展开更多
Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and s...Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and single crystal X-ray diffraction.Furthermore,all four compounds(most notably compound 7a) were found to be highly efficient against hepatitis B virus (HBV) in cultured HepG2 2.2.15 cell,making them promising drug candidates for potential bioactive molecule against hepatitis B.展开更多
Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst u...Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst under solvent-free conditions at room temperature.For unsymmetrical o-phenylenediamines bearing electron-withdrawing groups,regio-selective quinoxalines were obtained.展开更多
The catalytic system of[2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl)]nickel chloride/MAO(methylalu- minoxane)was found to be good active for vinyl polymerization of norbornene and provided polymers with relative...The catalytic system of[2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl)]nickel chloride/MAO(methylalu- minoxane)was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions.Various reaction parameters,such as the ratios of nickel precursor to MAO or monomer norbornene, and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities, polymer molecular weight and molecular we...展开更多
A series of novel 2-phenyl-10-substituted hymenialdisine derivatives was synthesized via the micro-wave-assisted Suzuki-Miyaura cross-coupling reactions of the 2-phenyl derivative of hymenialdisine and boronic acid, w...A series of novel 2-phenyl-10-substituted hymenialdisine derivatives was synthesized via the micro-wave-assisted Suzuki-Miyaura cross-coupling reactions of the 2-phenyl derivative of hymenialdisine and boronic acid, which enabled the successful introduction of electron-donating and electron-withdrawing groups to the 2-phenyl- hymenialdisine derivatives in good yields.展开更多
In an attempt to find new antitumor agents,a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chro...In an attempt to find new antitumor agents,a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chromone acids as the starting materials. During the preparation process,it was found that PPA could cleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone compound(5) to the ring-opening compound(6) varied with the change of reaction temperature and time. Based on MTT protocol,the antitumor activity of each of the compounds obtained was evaluated against three human cancer cell lines: KB(oral epidermal),A2780(ovary) and Bel7402(liver). The IC_ 50 varied from 54.7 μmol/L to more than 180 μmol/L.展开更多
Cyclopropanedicarboxylic anhydride can be converted to 4-substituted (or 4-spiro-)3-oxabicyclo[3.1.0]hexan-2-one by addition of Grignard (or α,ω-di-Crignard) reagents in ether or tetrahydrofuran solution.
Asymmetric hydrogenation of tetrasubstituted alkenes is an important but challenging research topic.Herein,we report an efficient iridium-catalyzed asymmetric hydrogenation of tetrasubstituted α,β-unsaturated ketone...Asymmetric hydrogenation of tetrasubstituted alkenes is an important but challenging research topic.Herein,we report an efficient iridium-catalyzed asymmetric hydrogenation of tetrasubstituted α,β-unsaturated ketones for the synthesis of chiral 2-substituted cyclopentyl aryl ketones,an important chiral structural motif for the preparation of chiral pharmaceuticals and bioactive molecules.The reaction proceeded very well with good functional group compatibility and delivered the hydrogenated products in high yields and stereoselectivities(up to 99% yield,>20:1 dr and 99%ee).In addition,the reaction could be carried out on a gram-scale,and all four stereoisomers of the hydrogenated products bearing two contiguous stereocenters were obtained.Furthermore,the hydrogenated product can be transformed into the ERβ agonist Erteberel,and the reaction pathway was also studied via deuterium-labelling experiments.展开更多
文摘In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity.The results of antibacterial activities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity,and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues 7a and 7b.
基金Education Department of Zhejiang Province(No.20060811) for the financial support of this work.
文摘A simple and efficient procedure for the synthesis of substituted benzothiazoles through condensation of 2-aminothiophenol with aromatic aldehydes in the presence of H2O2/HCl system in ethanol at room temperature is described. The target compounds have been characterized by ^1H NMR, ^13C NMR, IR and MS. Short reaction time, easy and quick isolation of the products, and excellent yields are the main advantages of this procedure.
文摘Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.
文摘Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and single crystal X-ray diffraction.Furthermore,all four compounds(most notably compound 7a) were found to be highly efficient against hepatitis B virus (HBV) in cultured HepG2 2.2.15 cell,making them promising drug candidates for potential bioactive molecule against hepatitis B.
基金Supported by the National Natural Science Foundation of China(Nos.20772088,21172163)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(No.JSSYSXK2010007)
文摘Ga（ClO4）3-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%（molar fraction） catalyst under solvent-free conditions at room temperature.For unsymmetrical o-phenylenediamines bearing electron-withdrawing groups,regio-selective quinoxalines were obtained.
文摘The catalytic system of[2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl)]nickel chloride/MAO(methylalu- minoxane)was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions.Various reaction parameters,such as the ratios of nickel precursor to MAO or monomer norbornene, and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities, polymer molecular weight and molecular we...
基金Supported by the National Natural Science Foundation of China(No.21002066)the Scientific Research Foundation for Young Teachers of Sichuan University,China(No.2009SCU11181)
文摘A series of novel 2-phenyl-10-substituted hymenialdisine derivatives was synthesized via the micro-wave-assisted Suzuki-Miyaura cross-coupling reactions of the 2-phenyl derivative of hymenialdisine and boronic acid, which enabled the successful introduction of electron-donating and electron-withdrawing groups to the 2-phenyl- hymenialdisine derivatives in good yields.
文摘In an attempt to find new antitumor agents,a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chromone acids as the starting materials. During the preparation process,it was found that PPA could cleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone compound(5) to the ring-opening compound(6) varied with the change of reaction temperature and time. Based on MTT protocol,the antitumor activity of each of the compounds obtained was evaluated against three human cancer cell lines: KB(oral epidermal),A2780(ovary) and Bel7402(liver). The IC_ 50 varied from 54.7 μmol/L to more than 180 μmol/L.
文摘Cyclopropanedicarboxylic anhydride can be converted to 4-substituted (or 4-spiro-)3-oxabicyclo[3.1.0]hexan-2-one by addition of Grignard (or α,ω-di-Crignard) reagents in ether or tetrahydrofuran solution.
基金supported by the National Key R&D Program of China(No.2018YFE0126800)the National Natural Science Foundation of China(Nos.21991112 and 22001164)the Shanghai Pujiang Program(20PJ1406400).
文摘Asymmetric hydrogenation of tetrasubstituted alkenes is an important but challenging research topic.Herein,we report an efficient iridium-catalyzed asymmetric hydrogenation of tetrasubstituted α,β-unsaturated ketones for the synthesis of chiral 2-substituted cyclopentyl aryl ketones,an important chiral structural motif for the preparation of chiral pharmaceuticals and bioactive molecules.The reaction proceeded very well with good functional group compatibility and delivered the hydrogenated products in high yields and stereoselectivities(up to 99% yield,>20:1 dr and 99%ee).In addition,the reaction could be carried out on a gram-scale,and all four stereoisomers of the hydrogenated products bearing two contiguous stereocenters were obtained.Furthermore,the hydrogenated product can be transformed into the ERβ agonist Erteberel,and the reaction pathway was also studied via deuterium-labelling experiments.
