The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed ...The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.展开更多
In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl gro...In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.展开更多
Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that...Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.展开更多
In the presence of BiCl3/Al or BiCl3/Fe, in THF-H2O, allylic (benzylic) bromides or α-bromoketones react with diorganyl diselenides to give allylic (benzylic) selenides orα-organylselenocarbonyl compounds respective...In the presence of BiCl3/Al or BiCl3/Fe, in THF-H2O, allylic (benzylic) bromides or α-bromoketones react with diorganyl diselenides to give allylic (benzylic) selenides orα-organylselenocarbonyl compounds respectively in moderate to good yields.展开更多
The fused heterocyclic compounds 2 : imidazo [1.2-a] pyriding 2a-c and pyrido [ 1 .2-a] pyrimidine 2d were obtained from the reaction of α-cinnamoyl ketene dibenzylthio acetals 1 with diamine. When α-cinnamoyl -a...The fused heterocyclic compounds 2 : imidazo [1.2-a] pyriding 2a-c and pyrido [ 1 .2-a] pyrimidine 2d were obtained from the reaction of α-cinnamoyl ketene dibenzylthio acetals 1 with diamine. When α-cinnamoyl -a'-benzoyl ketene N. N-acetals 3a-b were treated by t-BuONa/t- BuOH Solution. 8- benzoyl-pyrido[1.2-a] pyrimidine 4 was produced.展开更多
N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted additio...N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.展开更多
Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The...Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.展开更多
Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran der...Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.展开更多
Lassa hemorrhagic fever,caused by Lassa mammarenavirus(LASV)infection,accumulates up to 5000 deaths every year.Currently,there is no vaccine available to combat this disease.In this study,a library of 200 bioactive co...Lassa hemorrhagic fever,caused by Lassa mammarenavirus(LASV)infection,accumulates up to 5000 deaths every year.Currently,there is no vaccine available to combat this disease.In this study,a library of 200 bioactive compounds was virtually screened to study their drug-likeness with the capacity to block theα-dystroglycan(α-DG)receptor and prevent LASV influx.Following rigorous absorption,distribution,metabolism,and excretion(ADME)and quantitative structure-activity relationship(QSAR)profiling,molecular docking was conducted with the top ligands against theα-DG receptor.The compounds chrysin,reticuline,and 3-caffeoylshikimic acid emerged as the top three ligands in terms of binding affinity.Post-docking analysis revealed that interactions with Arg76,Asn224,Ser259,and Lys302 amino acid residues of the receptor protein were important for the optimum binding affinity of ligands.Molecular dynamics simulation was performed comprehensively to study the stability of the protein-ligand complexes.In-depth assessment of root-mean-square deviation(RMSD),root mean square fluctuation(RMSF),polar surface area(PSA),B-Factor,radius of gyration(Rg),solvent accessible surface area(SASA),and molecular surface area(MolSA)values of the protein-ligand complexes affirmed that the candidates with the best binding affinity formed the most stable protein-ligand complexes.To authenticate the potentialities of the ligands as target-specific drugs,an in vivo study is underway in real time as the continuation of the research.展开更多
α-C(sp^(3))-H arylation is an important type of C-H functionalization.Various biologically significant natural products,chemi-cal intermediates,and drugs have been effectively prepared via C-H functionalization.Cycli...α-C(sp^(3))-H arylation is an important type of C-H functionalization.Various biologically significant natural products,chemi-cal intermediates,and drugs have been effectively prepared via C-H functionalization.Cyclic carbonyl compounds comprise of cyclic ketones,enones,lactones,and lactams.Theα-C(sp^(3))-H arylation of these compounds have been exhibited high efficiency in forming C(sp^(3))-C(sp^(2))bonds,played a crucial role in organic synthesis,and attracted majority of interests from organic and medicinal communities.This review focused on the most significant advances including methods,mechanism,and applications in total synthesis of natural products in the field ofα-C(sp^(3))-H arylations of cyclic carbonyl compounds in recent years.展开更多
基金supported by National Natural Science Foundation of China(Nos.31871861 and 31501548)The Apicultural Industry Technology System(NCYTI-43-KXJ17)The Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2015-IAR)。
文摘The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.
基金The authors gratefully acknowledge the financial support of the Natural Science Foundation of China,China(Grant No.21975082 and 21736003)the Guangdong Basic and Applied Basic Research Foundation(Grant Number:2019A1515011472 and 2022A1515011341)the Science and Technology Program of Guangzhou(Grant Number:202102080479).
文摘In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.
文摘Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.
基金the Natural Science Foundation of the Education Commission of Jiangsu Province
文摘In the presence of BiCl3/Al or BiCl3/Fe, in THF-H2O, allylic (benzylic) bromides or α-bromoketones react with diorganyl diselenides to give allylic (benzylic) selenides orα-organylselenocarbonyl compounds respectively in moderate to good yields.
文摘The fused heterocyclic compounds 2 : imidazo [1.2-a] pyriding 2a-c and pyrido [ 1 .2-a] pyrimidine 2d were obtained from the reaction of α-cinnamoyl ketene dibenzylthio acetals 1 with diamine. When α-cinnamoyl -a'-benzoyl ketene N. N-acetals 3a-b were treated by t-BuONa/t- BuOH Solution. 8- benzoyl-pyrido[1.2-a] pyrimidine 4 was produced.
文摘N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.
基金supported by the National Natural Science Foundation of China (No. 20871071)the Science and Technology Commission Foundation of Tianjin (Nos. 09JCYBJC03600 and 10JCYBJC03900)
文摘Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeC13 aqueous solution followed by a calcination process. In the synthesis of porous α-Fe2O3, no templates or pore-directing agents were used. The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles. The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated. The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone, ether, methanol, ethanol, butanol and hexanol. Meanwhile, it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260 ℃. The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.
基金the National Natural Science Foundation of China (No.20676123) for financial support.
文摘Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.
文摘Lassa hemorrhagic fever,caused by Lassa mammarenavirus(LASV)infection,accumulates up to 5000 deaths every year.Currently,there is no vaccine available to combat this disease.In this study,a library of 200 bioactive compounds was virtually screened to study their drug-likeness with the capacity to block theα-dystroglycan(α-DG)receptor and prevent LASV influx.Following rigorous absorption,distribution,metabolism,and excretion(ADME)and quantitative structure-activity relationship(QSAR)profiling,molecular docking was conducted with the top ligands against theα-DG receptor.The compounds chrysin,reticuline,and 3-caffeoylshikimic acid emerged as the top three ligands in terms of binding affinity.Post-docking analysis revealed that interactions with Arg76,Asn224,Ser259,and Lys302 amino acid residues of the receptor protein were important for the optimum binding affinity of ligands.Molecular dynamics simulation was performed comprehensively to study the stability of the protein-ligand complexes.In-depth assessment of root-mean-square deviation(RMSD),root mean square fluctuation(RMSF),polar surface area(PSA),B-Factor,radius of gyration(Rg),solvent accessible surface area(SASA),and molecular surface area(MolSA)values of the protein-ligand complexes affirmed that the candidates with the best binding affinity formed the most stable protein-ligand complexes.To authenticate the potentialities of the ligands as target-specific drugs,an in vivo study is underway in real time as the continuation of the research.
基金We gratefully acknowledge financial support from the National Science of Foundation of China(81960631)the Yunnan Fundamental Research Project(202001AS070038)+1 种基金the Top Young Talent of Ten Thousand Talents Program of Yunnan Province(R.Zhan and L.-D Shao)the Start-up Fund of Yunnan University of Chinese Medicine(2019YZG03).
文摘α-C(sp^(3))-H arylation is an important type of C-H functionalization.Various biologically significant natural products,chemi-cal intermediates,and drugs have been effectively prepared via C-H functionalization.Cyclic carbonyl compounds comprise of cyclic ketones,enones,lactones,and lactams.Theα-C(sp^(3))-H arylation of these compounds have been exhibited high efficiency in forming C(sp^(3))-C(sp^(2))bonds,played a crucial role in organic synthesis,and attracted majority of interests from organic and medicinal communities.This review focused on the most significant advances including methods,mechanism,and applications in total synthesis of natural products in the field ofα-C(sp^(3))-H arylations of cyclic carbonyl compounds in recent years.
