A simplified procedure for enantioselective synthesis of (S)-(+)-2-(6-methoxyl-2- naphthyl) propionic acid ((S)-(+)-naproxen), starting from (6-methoxy-a-naphthyl) -1-propanone, with D-mannitol as auxiliary catalyzed ...A simplified procedure for enantioselective synthesis of (S)-(+)-2-(6-methoxyl-2- naphthyl) propionic acid ((S)-(+)-naproxen), starting from (6-methoxy-a-naphthyl) -1-propanone, with D-mannitol as auxiliary catalyzed by SmCl3 in onepot is described. The yield is 87.5 %(ee value 99 %).展开更多
CRISPR-Cas12a system has been shown promising for nucleic acid diagnostics due to its rapid,portable and accurate features.However,cleavage of the amplicons and primers by the cis-and trans-activity of Cas12a hinders ...CRISPR-Cas12a system has been shown promising for nucleic acid diagnostics due to its rapid,portable and accurate features.However,cleavage of the amplicons and primers by the cis-and trans-activity of Cas12a hinders the attempts to integrate the amplification and detection into a single reaction.Through phosphorothioate modification of primers,we realized onepot detection with high sensitivity using plasmids of SARS-CoV-2,HPV16 and HPV18.We also identified the activated Cas12a has a much higher affinity to C nucleotide-rich reporter than others.By applying such reporters,the reaction time required for a lateral-flow readout was significantly reduced.Furthermore,to improve the specificity of the strip-based assay,we created a novel reporter and,when combined with a customized gold-nanopaticle strip,the readout was greatly enhanced owing to the elimination of the nonspecific signal.This established system,termed Targeting DNA by Cas12a-based Eye Sight Testing in an Onepot Reaction(TESTOR),was validated using clinical cervical scrape samples for human papillomaviruses(HPVs)detection.Our system represents a general approach to integrating the nucleic acid amplification and detection into a single reaction in CRISPR-Cas systems,highlighting its potential as a rapid,portable and accurate detection platform of nucleic acids.展开更多
Chemical glycosylation methodologies for the preparation of the bioactive oligosaccharides and glycoconjugates promise reliable access to these compounds as homogeneous materials with welldefined structures in suffici...Chemical glycosylation methodologies for the preparation of the bioactive oligosaccharides and glycoconjugates promise reliable access to these compounds as homogeneous materials with welldefined structures in sufficient amounts.Here we report a novel activation method of thio(seleno)glycosides employing donor-acceptor cyclopropane(DAC)agents and Sc(OTf)_(3).The Lewis acid catalyst converts DAC into a formal 1,3-zwitterionic species that in turn activates thioglycosides to furnish a glycosyl 1,4-zwitterionic intermediate,interconverting with reactive glycosyl oxocarbenium in the solution with reversible leaving-group dissociation.This activation method effectively promotes glycosylation reactions between both armed and disarmed thioglycosides and structurally diverse acceptors,affording oligosaccharides with satisfactory yields.The usefulness of our activation method has been demonstrated by the mechanism-inspired 2,4-dinitrobenzenesulfonyl(DNs)group directed S_(N)2-like glycosylation and the facile preparation of both linear and branched trisaccharides in one pot via controlled sequential activation of thioglycoside donors.展开更多
文摘A simplified procedure for enantioselective synthesis of (S)-(+)-2-(6-methoxyl-2- naphthyl) propionic acid ((S)-(+)-naproxen), starting from (6-methoxy-a-naphthyl) -1-propanone, with D-mannitol as auxiliary catalyzed by SmCl3 in onepot is described. The yield is 87.5 %(ee value 99 %).
基金This work was supported by the Discipline Construction Ability Promotion Project of Shenzhen Health and Population Family Planning Commission(NO.SZXJ2018031(Kan L.J.))Sanming Project of Medicine in Shenzhen(NO.SZSM201601062(Zhang X.M.))Shenzhen Key Medical Discipline Construction Fund(NO.SZXK054(Zhang X.M.)).
文摘CRISPR-Cas12a system has been shown promising for nucleic acid diagnostics due to its rapid,portable and accurate features.However,cleavage of the amplicons and primers by the cis-and trans-activity of Cas12a hinders the attempts to integrate the amplification and detection into a single reaction.Through phosphorothioate modification of primers,we realized onepot detection with high sensitivity using plasmids of SARS-CoV-2,HPV16 and HPV18.We also identified the activated Cas12a has a much higher affinity to C nucleotide-rich reporter than others.By applying such reporters,the reaction time required for a lateral-flow readout was significantly reduced.Furthermore,to improve the specificity of the strip-based assay,we created a novel reporter and,when combined with a customized gold-nanopaticle strip,the readout was greatly enhanced owing to the elimination of the nonspecific signal.This established system,termed Targeting DNA by Cas12a-based Eye Sight Testing in an Onepot Reaction(TESTOR),was validated using clinical cervical scrape samples for human papillomaviruses(HPVs)detection.Our system represents a general approach to integrating the nucleic acid amplification and detection into a single reaction in CRISPR-Cas systems,highlighting its potential as a rapid,portable and accurate detection platform of nucleic acids.
基金the National Natural Science Foundation of China(grant no.22207092)the Natural Science Basic Research Plan of Shaanxi Province of China(grant no.2022JQ-091)+3 种基金the Fundamental Research Funds for the Central Universities(grant no.G2021KY05117)from Chinathe National Research Foundation(grant no.NRF-CRP22-2019-0002)the Ministry of Education(grant no.MOE-T2EP30120-0007)A*STAR(grant no.A20E5c0087)from Singapore for their financial support of this research.
文摘Chemical glycosylation methodologies for the preparation of the bioactive oligosaccharides and glycoconjugates promise reliable access to these compounds as homogeneous materials with welldefined structures in sufficient amounts.Here we report a novel activation method of thio(seleno)glycosides employing donor-acceptor cyclopropane(DAC)agents and Sc(OTf)_(3).The Lewis acid catalyst converts DAC into a formal 1,3-zwitterionic species that in turn activates thioglycosides to furnish a glycosyl 1,4-zwitterionic intermediate,interconverting with reactive glycosyl oxocarbenium in the solution with reversible leaving-group dissociation.This activation method effectively promotes glycosylation reactions between both armed and disarmed thioglycosides and structurally diverse acceptors,affording oligosaccharides with satisfactory yields.The usefulness of our activation method has been demonstrated by the mechanism-inspired 2,4-dinitrobenzenesulfonyl(DNs)group directed S_(N)2-like glycosylation and the facile preparation of both linear and branched trisaccharides in one pot via controlled sequential activation of thioglycoside donors.
