The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-oTr model. Combined with local hard-soft and acid-base （HSAB） principle, we made reasonable explanation by calculating local sof...The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-oTr model. Combined with local hard-soft and acid-base （HSAB） principle, we made reasonable explanation by calculating local softness of atom and bond regions for the stereoselectivity of four Diels-Alder reactions involving cyclopentadiene.展开更多
Molecular structures of reactants were characterized by molecular electronegativity distance vector （VHMED） considering hydrogen association. A reasonable molecular modeling equation with 4-parameters was achieved f...Molecular structures of reactants were characterized by molecular electronegativity distance vector （VHMED） considering hydrogen association. A reasonable molecular modeling equation with 4-parameters was achieved for quantitative structure-property/activity relationship （QSPR/QSAR） by stepwise multiple regression （SMR） that the variable was introduced item by item in significant level order. A high correlation coefficient （R = 0.980） demonstrates that the model is able to well express a quantitative relation between stereoselectivity and the reactant structures as quantitative structure-reactivity/stereoselectivity relationship （QSRR/QSSR）. The multiple correlation coefficient （Rcv= 0.964） was tested through cross-validation with the leave-one-out （LOO） procedure. The above results show that the model possesses high estimation stability and good prediction ability between the amount of both cis and trans isomers in products and reactants.展开更多
(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1...(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.展开更多
3-Deoxy-D-manno–oct-2-ulosonic acid(Kdo)is widely distributed in bacteria,and the synthesis of Kdocontaining oligosaccharides is important for the development of novel antibiotics and immunological agents.We have rec...3-Deoxy-D-manno–oct-2-ulosonic acid(Kdo)is widely distributed in bacteria,and the synthesis of Kdocontaining oligosaccharides is important for the development of novel antibiotics and immunological agents.We have recently developed a strategy to achieveα-stereocontrolled glycosylation using a C3-p-tolylthio-substituted Kdo phosphite donor.The wide substrate scope and high reactivity of the donors enabled the efficient synthesis of a series of Kdo-containing glycosides with completeα-stereoselectivity and without the formation of 2,3-ene byproducts.In this study,we improved the method by replacing the leaving group diethyl phosphite with fluoride,which enhanced the stability of the donor and led to cleaner reaction.Furthermore,the substrate range was expanded by synthesizing a series of Kdo O/C/S/Nglycosides,which also opened up a new avenue for the synthesis of CMP-Kdo synthase inhibitors.展开更多
What is the most favorite and original chemistry developed in your research group? Developing PIP amine for regio-and enantioselective methylene C-H activation. How do you get into this specific field? Could you pleas...What is the most favorite and original chemistry developed in your research group? Developing PIP amine for regio-and enantioselective methylene C-H activation. How do you get into this specific field? Could you please share some experiences with our readers?展开更多
Recently, there has been considerable attention focused on the binding of metal complexes to DNA. Since the middle 1980s, Barton et al. have found that the chirl octahedral complexes that contain planar aromatic ligan...Recently, there has been considerable attention focused on the binding of metal complexes to DNA. Since the middle 1980s, Barton et al. have found that the chirl octahedral complexes that contain planar aromatic ligands can bind to double-helical DNA stereoselectively, and the chirl intercalator [Ru（phen）<sub>3</sub>]<sup>3+</sup> has been used as the probe to recognize B and Z-form DNA. The photophysical studies indicated that the complexes containing 1, 10-phenanthroline or larger planar aromatic ligands can be intercalated into DNA stereoselectively and the complexes containing smaller ligands such as 2, 2’-展开更多
From (+)- camphor, six new (+)-camphor derivatives were synthesized. According tothe structure and chemical properties of the derivatives, the relation between the substitutedgroups and the stereoselectivity of alkyla...From (+)- camphor, six new (+)-camphor derivatives were synthesized. According tothe structure and chemical properties of the derivatives, the relation between the substitutedgroups and the stereoselectivity of alkylations and reduction was examined. It is found thatthe chemical shift of protons of C(8), C(9) methyl groups and chemical properties of carbonylO(2) are associated with the substituted groups.展开更多
The authors regret that in the original article,the structure of(–)-swainsonine(1)in Graphical abstract,Fig.1,Schemes 1 and 3 was incorrect.The correct structure is shown here.
Twenty one 1,3 dioxolanes with varieties of substituents at 2,4 positions were synthesized by acid catalyzed acetalization and ketalization reactions of glycerol and its modified derivatives. The assignment and qua...Twenty one 1,3 dioxolanes with varieties of substituents at 2,4 positions were synthesized by acid catalyzed acetalization and ketalization reactions of glycerol and its modified derivatives. The assignment and quantitative analyses of thermodynamically equilibrated cis and trans 1,3 dioxolanes were completed by 1H NMR. The stereoselective regularity was found in acetalization and ketalization reactions of glycerol and its modified derivatives. The stereoselective regularity of the condensation reactions was reasonably explained by anomeric effect and 2,4 nonbonded interaction.展开更多
An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high r...An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.展开更多
Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-san...Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.展开更多
The dynamic kinetic asymmetric transformation of racemic propargylic ammonium salts with prochiral aldimine esters through a stereodivergent propargylation is catalyzed by dual nickel and copper catalysis.Thus,a diver...The dynamic kinetic asymmetric transformation of racemic propargylic ammonium salts with prochiral aldimine esters through a stereodivergent propargylation is catalyzed by dual nickel and copper catalysis.Thus,a diverse range of optically activeα-quaternary amino esters were produced via C-N bond cleavage with high reaction efficiency and stereoselectivity(up to>99%ee).By selection of the appropriate pair-wise combination of catalyst configurational isomers,all four possible stereoisomers of the corresponding propargylation products are obtained in high yields with excellent regio-,diastereo-,and enantioselectiv-ities.展开更多
A mild base-promoted three-component deconstructive functionalization of exocyclic 1,3-dicarbonyls with aryl diazonium tetrafluoroborates in the presence of alcohols is reported,enabling direct ring-opening of unstrai...A mild base-promoted three-component deconstructive functionalization of exocyclic 1,3-dicarbonyls with aryl diazonium tetrafluoroborates in the presence of alcohols is reported,enabling direct ring-opening of unstrained cyclic ring systems to produce six types of skeletally diverse hydrazonylated 1,n-diesters(e.g.,1,6-,1,7-1,8-,and 1,9-diesters)and 1,n-ketoesters(e.g.,1,6-and 1,7-ketoesters)with good yields,and the latter demonstrated complete(E)-selectivity.The methodology has the potential to be widely used throughout organic synthesis due to the use of easily accessible substrates with different substitution patterns,such as exocyclic 1,3-carbonyls and aryl diazonium tetrafluoroborates,and mild reaction conditions.Preliminary biological evaluation of some compounds,namely their inhibitory effect on human lung cancer cell MSTO-211H,was conducted.The results showed that compounds 3c and 3w exhibited significant inhibitory effects.展开更多
2-Deoxy-α-C-Glycosides are a significant class of carbohydrates found in numerous bioactive molecules and medicines.Developing a concise strategy for the assembly of theseα-configured C-glycosides is crucial in the ...2-Deoxy-α-C-Glycosides are a significant class of carbohydrates found in numerous bioactive molecules and medicines.Developing a concise strategy for the assembly of theseα-configured C-glycosides is crucial in the field of carbohydrate chemistry.However,current methods are restricted to the utilization of glycosyl radical precursors,which are required for pre-syntheses.Herein,we present a novel approach for the synthesis of 2-deoxy-α-C-glycosides using a nickel-catalyzed stereoselective coupling reaction with commercially available glycals.Notably,this method circumvents the preparation for diverse glycosyl radical precursors.The developed protocol exhibits a broad substrate scope and remarkable stereoselectivity under mild reaction conditions.Furthermore,the raw materials required for this process are readily accessible,eliminating the necessity for pre-functionalization modifications of the glycosyl substrates and ensuring high atomic economy.展开更多
Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analys...Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analysis.EstSIT01 demonstrated remarkable efficiency in asymmetrically hydrolyzing meso-dimethyl ester[Dimethyl cis-1,3-Dibenzyl-2-imidazolidine-4,5-dicarboxyate],producing over 99%yield and 99%enantiomeric excess(e.e.)for(4S,5R)-monomethyl ester,a crucial chiral intermediate during the synthesis of d-biotin.Notably,the recombinant E.coli expressing EstSIT01 exhibited over 40-fold higher activity than that of the wild strain.EstSIT01 displays a preference for short-chain p-NP esters.The optimal temperature and pH were 45°C and 10.0,with Km and kcat values of 0.147 mmol/L and 5.808 s−1,respectively.Molecular docking and MD simulations suggest that the high stereoselectivity for meso-diester may attribute to the narrow entrance tunnel and unique binding pocket structure.Collectively,EstSIT01 holds great potential for preparing chiral carboxylic acids and esters.展开更多
To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcoh...To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.展开更多
We report a novel P-directing effect of imidazolium based ionic liquid,which was observed when we conducted the glycosylation of a 6-O-acetyl-2,3,4-tri-O-benzyl-mannose trichloroacetimidate donor with a modified ionic...We report a novel P-directing effect of imidazolium based ionic liquid,which was observed when we conducted the glycosylation of a 6-O-acetyl-2,3,4-tri-O-benzyl-mannose trichloroacetimidate donor with a modified ionic liquid support acceptor. The mechanism was investigated and a hypothesis was proposed.After optimization of the reaction conditions,an innovative method for the selective construction of 1,2-cis-β-D-mannopyranosyl linkage was developed.展开更多
The protein binding of non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac with human serum albumin （HSA） was investigated using indirect chiral high performance liquid chromatography （HPLC...The protein binding of non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac with human serum albumin （HSA） was investigated using indirect chiral high performance liquid chromatography （HPLC） and ultrafiltration techniques. S-（-）-1-（1-naphthyl）- ethylamine （S-NEA） was utilized as chiral derivatization reagent and pre-column derivatization RP-HPLC method was established for the separation and assay of the three pairs of enantiomer. The method had good linear relationship over the investigated concentration range without interference. The average extraction efficiency was higher than 85% in different systems, and the intra-day and inter-day precisions were less than 15%. In serum albumin, the protein binding of etodolac enantiomers showed significant stereoselectivity that the affinity of S-enantiomer was stronger than R-enantiomer, and the stereoselectivity ratio reached 6.06; Flurbiprofen had only weak stereoselectivity in HSA, and ketoprofen had no stereoselectivity at all. Scatchard curves showed that all the three chiral drugs had two types of binding sites in HSA.展开更多
β-Iminophosphonamide ligated lanthanum bis（benzyl） complex（NPNDipp）La（CH2Ph-4-Me）2（THF）（NPNDipp = Ph2P（NC6H3iPr2-2,6）2）, upon activation of Al Et3 and [Ph3C][B（C6F5）4], exhibited high catalytic activity...β-Iminophosphonamide ligated lanthanum bis（benzyl） complex（NPNDipp）La（CH2Ph-4-Me）2（THF）（NPNDipp = Ph2P（NC6H3iPr2-2,6）2）, upon activation of Al Et3 and [Ph3C][B（C6F5）4], exhibited high catalytic activity and high trans-1,4 stereoselectivity for the polymerization of bio-sourced b-myrcene（MY）. Based on which, a series of novel trans-1,4 regulated elastomers could be generated by random/block copolymerization of MY and isoprene（IP）.展开更多
基金the grants from the National Natural Science Foundation of China.(No.20633050 and 20403007).
文摘The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-oTr model. Combined with local hard-soft and acid-base （HSAB） principle, we made reasonable explanation by calculating local softness of atom and bond regions for the stereoselectivity of four Diels-Alder reactions involving cyclopentadiene.
文摘Molecular structures of reactants were characterized by molecular electronegativity distance vector （VHMED） considering hydrogen association. A reasonable molecular modeling equation with 4-parameters was achieved for quantitative structure-property/activity relationship （QSPR/QSAR） by stepwise multiple regression （SMR） that the variable was introduced item by item in significant level order. A high correlation coefficient （R = 0.980） demonstrates that the model is able to well express a quantitative relation between stereoselectivity and the reactant structures as quantitative structure-reactivity/stereoselectivity relationship （QSRR/QSSR）. The multiple correlation coefficient （Rcv= 0.964） was tested through cross-validation with the leave-one-out （LOO） procedure. The above results show that the model possesses high estimation stability and good prediction ability between the amount of both cis and trans isomers in products and reactants.
基金Financial supports from the National Key R&D Program of China(2018YFC1604100)the National Natural Science Foundation of China(NSFC)[21676120,31872891]+8 种基金the 111 Project[111-2-06]the Highend Foreign Experts Recruitment Program[G20190010083]the Program for Advanced Talents within Six Industries of Jiangsu Province[2015-NY007]the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities[JUSRP51504]the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsTop-notch Academic Programs Project of Jiangsu Higher Education Institutionsthe Jiangsu Province“Collaborative Innovation Center for Advanced Industrial Fermentation”Industry Development Programthe National First-Class Discipline Program of Light Industry Technology and Engineering[LITE2018-09]。
文摘(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.
基金supported by the National Key R&D Program of China(Nos.2022YFF1203005,2022YFC2303700)supported by the National Natural Science Foundation of China(Nos.81930097,82151223).
文摘3-Deoxy-D-manno–oct-2-ulosonic acid(Kdo)is widely distributed in bacteria,and the synthesis of Kdocontaining oligosaccharides is important for the development of novel antibiotics and immunological agents.We have recently developed a strategy to achieveα-stereocontrolled glycosylation using a C3-p-tolylthio-substituted Kdo phosphite donor.The wide substrate scope and high reactivity of the donors enabled the efficient synthesis of a series of Kdo-containing glycosides with completeα-stereoselectivity and without the formation of 2,3-ene byproducts.In this study,we improved the method by replacing the leaving group diethyl phosphite with fluoride,which enhanced the stability of the donor and led to cleaner reaction.Furthermore,the substrate range was expanded by synthesizing a series of Kdo O/C/S/Nglycosides,which also opened up a new avenue for the synthesis of CMP-Kdo synthase inhibitors.
文摘What is the most favorite and original chemistry developed in your research group? Developing PIP amine for regio-and enantioselective methylene C-H activation. How do you get into this specific field? Could you please share some experiences with our readers?
文摘Recently, there has been considerable attention focused on the binding of metal complexes to DNA. Since the middle 1980s, Barton et al. have found that the chirl octahedral complexes that contain planar aromatic ligands can bind to double-helical DNA stereoselectively, and the chirl intercalator [Ru（phen）<sub>3</sub>]<sup>3+</sup> has been used as the probe to recognize B and Z-form DNA. The photophysical studies indicated that the complexes containing 1, 10-phenanthroline or larger planar aromatic ligands can be intercalated into DNA stereoselectively and the complexes containing smaller ligands such as 2, 2’-
基金Project supported by the National Natural Science Foundation of China.
文摘From (+)- camphor, six new (+)-camphor derivatives were synthesized. According tothe structure and chemical properties of the derivatives, the relation between the substitutedgroups and the stereoselectivity of alkylations and reduction was examined. It is found thatthe chemical shift of protons of C(8), C(9) methyl groups and chemical properties of carbonylO(2) are associated with the substituted groups.
文摘The authors regret that in the original article,the structure of(–)-swainsonine(1)in Graphical abstract,Fig.1,Schemes 1 and 3 was incorrect.The correct structure is shown here.
文摘Twenty one 1,3 dioxolanes with varieties of substituents at 2,4 positions were synthesized by acid catalyzed acetalization and ketalization reactions of glycerol and its modified derivatives. The assignment and quantitative analyses of thermodynamically equilibrated cis and trans 1,3 dioxolanes were completed by 1H NMR. The stereoselective regularity was found in acetalization and ketalization reactions of glycerol and its modified derivatives. The stereoselective regularity of the condensation reactions was reasonably explained by anomeric effect and 2,4 nonbonded interaction.
文摘An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.
基金financially supported by the open research fund program of Science and Technology on Aerospace Chemical Power Laboratory (No. STACPL120221B03)the National Natural Science Foundation of China (Nos. s22175059,52073275 and U21A20279)。
文摘Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.
基金support from the National Natural Science Foundation of China(Nos.21702198,21971227)the Anhui Provincial Natural Science Foundation(No.1808085MB30)the Fundamental Research Funds for the Central Universities(No.WK2340000090).
文摘The dynamic kinetic asymmetric transformation of racemic propargylic ammonium salts with prochiral aldimine esters through a stereodivergent propargylation is catalyzed by dual nickel and copper catalysis.Thus,a diverse range of optically activeα-quaternary amino esters were produced via C-N bond cleavage with high reaction efficiency and stereoselectivity(up to>99%ee).By selection of the appropriate pair-wise combination of catalyst configurational isomers,all four possible stereoisomers of the corresponding propargylation products are obtained in high yields with excellent regio-,diastereo-,and enantioselectiv-ities.
文摘A mild base-promoted three-component deconstructive functionalization of exocyclic 1,3-dicarbonyls with aryl diazonium tetrafluoroborates in the presence of alcohols is reported,enabling direct ring-opening of unstrained cyclic ring systems to produce six types of skeletally diverse hydrazonylated 1,n-diesters(e.g.,1,6-,1,7-1,8-,and 1,9-diesters)and 1,n-ketoesters(e.g.,1,6-and 1,7-ketoesters)with good yields,and the latter demonstrated complete(E)-selectivity.The methodology has the potential to be widely used throughout organic synthesis due to the use of easily accessible substrates with different substitution patterns,such as exocyclic 1,3-carbonyls and aryl diazonium tetrafluoroborates,and mild reaction conditions.Preliminary biological evaluation of some compounds,namely their inhibitory effect on human lung cancer cell MSTO-211H,was conducted.The results showed that compounds 3c and 3w exhibited significant inhibitory effects.
基金supported by grants from the Fundamental Research Funds for Central Universities(No.2042021kf0190)。
文摘2-Deoxy-α-C-Glycosides are a significant class of carbohydrates found in numerous bioactive molecules and medicines.Developing a concise strategy for the assembly of theseα-configured C-glycosides is crucial in the field of carbohydrate chemistry.However,current methods are restricted to the utilization of glycosyl radical precursors,which are required for pre-syntheses.Herein,we present a novel approach for the synthesis of 2-deoxy-α-C-glycosides using a nickel-catalyzed stereoselective coupling reaction with commercially available glycals.Notably,this method circumvents the preparation for diverse glycosyl radical precursors.The developed protocol exhibits a broad substrate scope and remarkable stereoselectivity under mild reaction conditions.Furthermore,the raw materials required for this process are readily accessible,eliminating the necessity for pre-functionalization modifications of the glycosyl substrates and ensuring high atomic economy.
基金supported by the Shanghai Committee of Science and Technology(No.13430503400)Project of Leading Talents in Shandong Taishan Industry(Grant No.LJNY202019)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(No.ZX2012-05)Innovation Program of Shanghai Municipal Education Commission(No.11YZ227).
文摘Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analysis.EstSIT01 demonstrated remarkable efficiency in asymmetrically hydrolyzing meso-dimethyl ester[Dimethyl cis-1,3-Dibenzyl-2-imidazolidine-4,5-dicarboxyate],producing over 99%yield and 99%enantiomeric excess(e.e.)for(4S,5R)-monomethyl ester,a crucial chiral intermediate during the synthesis of d-biotin.Notably,the recombinant E.coli expressing EstSIT01 exhibited over 40-fold higher activity than that of the wild strain.EstSIT01 displays a preference for short-chain p-NP esters.The optimal temperature and pH were 45°C and 10.0,with Km and kcat values of 0.147 mmol/L and 5.808 s−1,respectively.Molecular docking and MD simulations suggest that the high stereoselectivity for meso-diester may attribute to the narrow entrance tunnel and unique binding pocket structure.Collectively,EstSIT01 holds great potential for preparing chiral carboxylic acids and esters.
文摘To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.
基金National Natural Science Foundation of China (Grant No.20732001) the State New Drug Innovation(the Ministry of Science and Technology of China,Grant No. 2009ZX09501-011)
文摘We report a novel P-directing effect of imidazolium based ionic liquid,which was observed when we conducted the glycosylation of a 6-O-acetyl-2,3,4-tri-O-benzyl-mannose trichloroacetimidate donor with a modified ionic liquid support acceptor. The mechanism was investigated and a hypothesis was proposed.After optimization of the reaction conditions,an innovative method for the selective construction of 1,2-cis-β-D-mannopyranosyl linkage was developed.
基金supported by National Major Projects for Science and Technology Development of Ministry Science and Technology of China (2009ZX09304-003)
文摘The protein binding of non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac with human serum albumin （HSA） was investigated using indirect chiral high performance liquid chromatography （HPLC） and ultrafiltration techniques. S-（-）-1-（1-naphthyl）- ethylamine （S-NEA） was utilized as chiral derivatization reagent and pre-column derivatization RP-HPLC method was established for the separation and assay of the three pairs of enantiomer. The method had good linear relationship over the investigated concentration range without interference. The average extraction efficiency was higher than 85% in different systems, and the intra-day and inter-day precisions were less than 15%. In serum albumin, the protein binding of etodolac enantiomers showed significant stereoselectivity that the affinity of S-enantiomer was stronger than R-enantiomer, and the stereoselectivity ratio reached 6.06; Flurbiprofen had only weak stereoselectivity in HSA, and ketoprofen had no stereoselectivity at all. Scatchard curves showed that all the three chiral drugs had two types of binding sites in HSA.
基金financially supported by the National Natural Science Foundation of China(Nos.51321062 and 21304088)the Department of Science and Technology of Jilin Province for Project No.20150204079GX
文摘β-Iminophosphonamide ligated lanthanum bis（benzyl） complex（NPNDipp）La（CH2Ph-4-Me）2（THF）（NPNDipp = Ph2P（NC6H3iPr2-2,6）2）, upon activation of Al Et3 and [Ph3C][B（C6F5）4], exhibited high catalytic activity and high trans-1,4 stereoselectivity for the polymerization of bio-sourced b-myrcene（MY）. Based on which, a series of novel trans-1,4 regulated elastomers could be generated by random/block copolymerization of MY and isoprene（IP）.
