A green and highly efficient synthetic method for the synthesis of quinazoline-2,4-diones with hydrogen peroxide as the terminal oxidant has been developed, The reaction features the mild reaction conditions, broad su...A green and highly efficient synthetic method for the synthesis of quinazoline-2,4-diones with hydrogen peroxide as the terminal oxidant has been developed, The reaction features the mild reaction conditions, broad substrate scope, metal-free catalysts, and sole byproduct water. A plausible mechanism for this process was proposed. Moreover, an antibacterial activity study was performed to evaluate the antimicrobial activities towards two Gram-negative bacterial strains （Escherichia coli, and Klebsiella pneumonia） and two Gram-positive bacterial strains （Staphylococcus epidermidis, and Staphylococcus aureus） using the Broth microdilution method.展开更多
Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-...Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-carbaldehydes has been described.The protocol employs mild conditions and offers good yields of diverse 2,5-aryloxazole derivatives with a broad reaction scope.It is amenable to gram-scale synthesis and easily transformation.Moreover,this 5-aryl-2-(quinolin-2-yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.展开更多
A convenient and metal-flee DMAP-catalyzed domino reaction of isatins, arylamines and hydroximoyl chlorides has been developed to achieve 1,3-dipolar cycloaddition of imines into aryl nitrile oxides at ambient tempera...A convenient and metal-flee DMAP-catalyzed domino reaction of isatins, arylamines and hydroximoyl chlorides has been developed to achieve 1,3-dipolar cycloaddition of imines into aryl nitrile oxides at ambient tempera- ture. In this one-pot transformation, a 1,2,4-oxadiazole skeleton was efficiently formed. This methodology needs no extra additives and features wide substrate scope, good functional group tolerance and mild reaction conditions. A plausible mechanism for this process was proposed. Moreover, the antibacterial activities of the products were evaluated towards Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using the Broth microdilution method.展开更多
The versatile photosyntheticα-proteobacterium Rhodobacter sphaeroides,has recently been extensively engineered as a novel microbial cell factory(MCF)to produce pharmaceuticals,nutraceuticals,commodity chemicals and e...The versatile photosyntheticα-proteobacterium Rhodobacter sphaeroides,has recently been extensively engineered as a novel microbial cell factory(MCF)to produce pharmaceuticals,nutraceuticals,commodity chemicals and even hydrogen.However,there are no well-characterized high-activity promoters to modulate gene transcription during the engineering of R.sphaeroides.In this study,several native promoters from R.sphaeroides JDW-710(JDW-710),an industrial strain producing high levels of co-enzyme Q10(Q10)were selected on the basis of transcriptomic analysis.These candidate promoters were then characterized by using gusA as a reporter gene.Two native promoters,Prsp_7571 and Prsp_6124,showed 620%and 800%higher activity,respectively,than the tac promoter,which has previously been used for gene overexpression in R.sphaeroides.In addition,a Prsp_7571-derived synthetic promoter library with strengths ranging from 54%to 3200%of that of the tac promoter,was created on the basis of visualization of red fluorescent protein(RFP)expression in R.sphaeroides.Finally,as a demonstration,the synthetic pathway of Q10 was modulated by the selected promoter T334*in JDW-710;the Q10 yield in shake-flasks increased 28%and the production reached 226 mg/L.These well-characterized promoters should be highly useful in current synthetic biology platforms for refactoring the biosynthetic pathway in R.sphaeroides-derived MCFs.展开更多
基金Supporting information for this article is available on the WWW under http：//dx.doi.org/10.1002/cjoc,201700280 or from the author.Acknowledgement The work was partially supported by the National Natural Science Foundation of China （No. 21172001, 21372008）, the Natural Science Foundation of Education Administration of Anhui Province （KJ2016A267）, the Special and Excellent Research Fund of Anhui Normal University and the Doctoral Scientific Research Foundation of Anhui Normal University （No. 2016XJJ110）.
文摘A green and highly efficient synthetic method for the synthesis of quinazoline-2,4-diones with hydrogen peroxide as the terminal oxidant has been developed, The reaction features the mild reaction conditions, broad substrate scope, metal-free catalysts, and sole byproduct water. A plausible mechanism for this process was proposed. Moreover, an antibacterial activity study was performed to evaluate the antimicrobial activities towards two Gram-negative bacterial strains （Escherichia coli, and Klebsiella pneumonia） and two Gram-positive bacterial strains （Staphylococcus epidermidis, and Staphylococcus aureus） using the Broth microdilution method.
基金the National Natural Sci-ence Foundation of China(No.21772001)the Anhui Provincial Natural Science Foundation(No.1808085MB41)the Cultiva-tion Project for University Outstanding Talents of Anhui Province(2019).
文摘Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-carbaldehydes has been described.The protocol employs mild conditions and offers good yields of diverse 2,5-aryloxazole derivatives with a broad reaction scope.It is amenable to gram-scale synthesis and easily transformation.Moreover,this 5-aryl-2-(quinolin-2-yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.
基金The work was partially supported by the National Natural Science Foundation of China （Nos. 21172001, 21372008）, the Natural Science Foundation of Education Administration of Anhui Province （No. KJ2016A267）, the Special and Excellent Research Fund of Anhui Normal University and the Doctoral Scientific Research Foundation of Anhui Normal University （No. 2016XJJ110）.
文摘A convenient and metal-flee DMAP-catalyzed domino reaction of isatins, arylamines and hydroximoyl chlorides has been developed to achieve 1,3-dipolar cycloaddition of imines into aryl nitrile oxides at ambient tempera- ture. In this one-pot transformation, a 1,2,4-oxadiazole skeleton was efficiently formed. This methodology needs no extra additives and features wide substrate scope, good functional group tolerance and mild reaction conditions. A plausible mechanism for this process was proposed. Moreover, the antibacterial activities of the products were evaluated towards Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using the Broth microdilution method.
基金This work was supported by the National Natural Science Foundation of China[31870040]the National Key Research and Development Project(2020YFA0907804,2020YFA0907304)+1 种基金the“111”Project of China[B18022]the Fundamental Research Funds for the Central Universities[22221818014],and the Open Project Funding of the State Key Laboratory of Bioreactor Engineering.
文摘The versatile photosyntheticα-proteobacterium Rhodobacter sphaeroides,has recently been extensively engineered as a novel microbial cell factory(MCF)to produce pharmaceuticals,nutraceuticals,commodity chemicals and even hydrogen.However,there are no well-characterized high-activity promoters to modulate gene transcription during the engineering of R.sphaeroides.In this study,several native promoters from R.sphaeroides JDW-710(JDW-710),an industrial strain producing high levels of co-enzyme Q10(Q10)were selected on the basis of transcriptomic analysis.These candidate promoters were then characterized by using gusA as a reporter gene.Two native promoters,Prsp_7571 and Prsp_6124,showed 620%and 800%higher activity,respectively,than the tac promoter,which has previously been used for gene overexpression in R.sphaeroides.In addition,a Prsp_7571-derived synthetic promoter library with strengths ranging from 54%to 3200%of that of the tac promoter,was created on the basis of visualization of red fluorescent protein(RFP)expression in R.sphaeroides.Finally,as a demonstration,the synthetic pathway of Q10 was modulated by the selected promoter T334*in JDW-710;the Q10 yield in shake-flasks increased 28%and the production reached 226 mg/L.These well-characterized promoters should be highly useful in current synthetic biology platforms for refactoring the biosynthetic pathway in R.sphaeroides-derived MCFs.
