A molecular structural characterization （MSC） method called molecular vertexes correlative index （MVCI） was used to describe the structures of 30 substituted aromatic compounds. Through multiple linear regression ...A molecular structural characterization （MSC） method called molecular vertexes correlative index （MVCI） was used to describe the structures of 30 substituted aromatic compounds. Through multiple linear regression （MLR） and stepwise multiple regression （SMR）, a quantitative structure-toxicity relationship （QSTR） model with 4 variables was obtained. The correlation coefficient （R） of the model was 0.9467. Through partial least-squares regression （PLS）, another QSTR model with 5 principal components was obtained. The correlation coefficient （R） of the model was 0.9518. Both models were evaluated by performing the cross-validation with the leave-one-out （LOO） procedure and the Cross-Validation （CV） correlation coefficients （Rcv） were 0.9208 and 0.9214, respectively. The results suggested good stability and predictability of the models, and the molecular vertexes correlative index could successfully describe the structures of the substituted aromatic compounds.展开更多
With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity...With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity relationship（QSAR） models to predict the acute toxicity（-lgEC50） of substituted aromatic compounds to Photobacterium phosphoreum were established.Four molecular descriptors that appear in the MLR model,namely,the second order valence molecular connectivity index（2XV）,the energy of the highest occupied molecular orbital（EHOMO）,the logarithm of n-octyl alcohol/water partition coefficient（logKow） and the Connolly molecular area（MA）,were inputs of the ANN model.The root-mean-square error（RMSE） of the training and validation sets of the ANN model are 0.1359 and 0.2523,and the correlation coefficient（R） is 0.9810 and 0.8681,respectively.The leave-one-out（LOO） cross validated correlation coefficient（Q L2OO） of the MLR and ANN models is 0.6954 and 0.6708,respectively.The result showed that the two methods are complementary in the calculations.The regression method gave support to the neural network with physical explanation,and the neural network method gave a more accurate model for QSAR.In addition,some insights into the structural factors affecting the acute toxicity and toxicity mechanism of substituted aromatic compounds were discussed.展开更多
Heteroatom-directed aromatic lithiation reactions used for the regiospecific synthesis of o-isopropyl substituted phenolic and benzyl alcoholic compounds are described.
Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free m...Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.展开更多
The knowledge of the existence,distribution and fate of polycyclic aromatic hydrocarbons(PAHs)and substituted polycyclic aromatic hydrocarbons(SPAHs)in wastewater treatment plants(WWTPs)was vital for reducing their co...The knowledge of the existence,distribution and fate of polycyclic aromatic hydrocarbons(PAHs)and substituted polycyclic aromatic hydrocarbons(SPAHs)in wastewater treatment plants(WWTPs)was vital for reducing their concentrations entering the aquatic environment.The concentrations of 13 SPAHs and 16 PAHs were all determined in a WWTP with styrene butadiene rubber(SBR)in partnership with the moving bed biofilm reactor(MBBR)process.SPAHs presented a higher concentration lever than PAHs in nearly all samples.The total removal efficiencies of PAHs and SPAHs ranged from 64.0%to 71.36%and 78.4%to 79.7%,respectively.The total yearly loads of PAHs(43.0 kg)and SPAHs(73.0 kg)were mainly reduced by the primary and SBR/MBBR biological treatment stages.The tertiary treatment stage had a minor contribution to target compounds removal.According to a synthesis and improvement fate model,we found that the dominant processes changed as the chemical octanol water partition coefficient(K_(ow))increased.But the seasonal variations of experimental removal efficiencies were more obvious than that of predicted data.In the primary sedimentation tank,dissolution in the aqueous phase and sorption to sludge/particulate matter were controlling processes for the removal of PAHs and SPAHs.The sorption to sludge and biodegradation were the principal removal mechanisms during the SBR/MBBR biological treatment process.The contribution of volatilization to removal was always insignificant.Furthermore,the basic physicochemical properties and operating parameters influenced the fate of PAHs and SPAHs in the WWTP.展开更多
Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformat...Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformation utilizes commercially available reagents,cheap electrodes,and simple equipment.Diverse aryl nitriles were successfully obtained in a direct and efficient way with broad substrate scope,excellent functional group tolerance,and selective C-O bond cleavage.Furthermore,late-stage modification of biorelevant compounds and gram-scale synthesis highlighted the potential application of the strategy.Mechanistic investigations suggest that the arene cation radical was considered as the key intermediate for the transformation,and undergoing the followed S_(N)Ar process.展开更多
The electrophilic aromatic substitution reactions have been studied by using the con- cept of pseudo orbital proposed by authors,Because the unoccupied orbitals of electrophilic reagents have been.taken into account,t...The electrophilic aromatic substitution reactions have been studied by using the con- cept of pseudo orbital proposed by authors,Because the unoccupied orbitals of electrophilic reagents have been.taken into account,the present results are better than ones given by superdelocalizability,S,.展开更多
It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. se...It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. self-condensation in aprotic polar solvent occurs to give symmnetrical disubstituted diphenyl ethers. However. when it is substituted with moderate electron withdrawing groups, no diphenyl ethers are obtained under the same conditions, instead, corresponding carboxylates are yielded. As a result. the applicability of this reaction is distinctly clarified展开更多
An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0...An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0-5 ℃, solvent： water） within a short reaction time （1 h）. A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.展开更多
Chaetoxanthone D（1）, a new tetrahydropyran-substituted xanthone originated from polyketide pathway, together with the four known natural products chaetoxanthone C（2）, alternariol methyl ether（3）, alternariol（4...Chaetoxanthone D（1）, a new tetrahydropyran-substituted xanthone originated from polyketide pathway, together with the four known natural products chaetoxanthone C（2）, alternariol methyl ether（3）, alternariol（4） and 2,5-dimethyl-7-hydroxychromone（5） was isolated from a strain of Chaetomium murorum. The structures of these compounds were elucidated based on extensive spectroscopic analyses. The absolute configurations of 1 and 2 were determined by using quantum chemical electronic circular dichroism（ECD） calculations.展开更多
A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of he...A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of height equivalent to a theoretical plate was 25 mu m and rapid separations of small molecules such as substituted aromatic hydrocarbons and aromatic acids were achieved within five minutes.展开更多
We report a series of highly stable metallophthalocyanine-based covalent organic frameworks(MPc-dxCOFs) linked by robust 1,4-dioxin bonds constructed through nucleophilic aromatic substitution(SNAr)reaction. The chemi...We report a series of highly stable metallophthalocyanine-based covalent organic frameworks(MPc-dxCOFs) linked by robust 1,4-dioxin bonds constructed through nucleophilic aromatic substitution(SNAr)reaction. The chemical structures and crystallinity of the COFs largely remain unchanged even after treating with boiling water(90°C), concentrated acids(12 mol/L HCl) or bases(12 mol/L Na OH), oxidizing(30% H_(2)O_(2)) or reducing agents(1 mol/L NaBH;) for three days due to their stable M-Pc building blocks and resilient dioxin linkers. With metallated phthalocyanine active sites regularly arranged in the stable framework structures, MPc-dx-COFs can be directly used as efficient electrocatalysts for the oxygen reduction reaction(ORR) without pyrolysis treatment that has commonly been used in previous studies.展开更多
An efficient and practical synthetic protocol to synthesize nonsymmetrical aryl thioethers by nucleophilic aromatic substitution(S_NAr)reaction of nitroarenes by thiols with potassium phosphate as the catalyst is desc...An efficient and practical synthetic protocol to synthesize nonsymmetrical aryl thioethers by nucleophilic aromatic substitution(S_NAr)reaction of nitroarenes by thiols with potassium phosphate as the catalyst is described.Various moderate to strong electron-withdrawing functional groups are tolerated by the system to provide thioethers in a good to excellent yields.We also showed that the present method allows access to 3 drug examples in a short reaction time.Finally,mechanistic studies suggest that the reaction may form the classic Meisenheimer complex through a two-step additionelimination mechanism.展开更多
A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtai...A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtained in moderate to high isolated yields（up to 82%） with good stereoselevtivities（up to 15：1） in the presence of 5 mol% of Cu（OAc）2at room temperature.展开更多
Tetrabutylammonium fluoride （TBAF） effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane （PhSTMS） under mild and base-free neutral conditions ...Tetrabutylammonium fluoride （TBAF） effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane （PhSTMS） under mild and base-free neutral conditions at room temperature, providing a practical and efficient synthesis of useful unsymmetrical diaryl thioethers. Nitroarenes bearing ortho- and para-positioned electron-withdrawing groups are the most reactive substrates, indicating that this reaction most possibly proceeded via the nucleophilic aromatic substitution （SNAr） mechanism.展开更多
The 1-azido-2-chloro-4-nitrobenzene was prepared by nucleophilic substitution between 2-chloro-4-nitro-1-(trifluoromethylsulfinyl)benzene and sodium azide, and its structure was characterized by NMR spectrum and X-ray...The 1-azido-2-chloro-4-nitrobenzene was prepared by nucleophilic substitution between 2-chloro-4-nitro-1-(trifluoromethylsulfinyl)benzene and sodium azide, and its structure was characterized by NMR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n, Z = 8 and Mr = 198.57. A cultivation process of the single crystal of unstable aryl azide was provided. The group of trifluoromethyl sulfinyl was found for the first time to be a new excellent leaving group of aromatic nucleophilic substitution reactions.展开更多
Unsymmetrical sulfides can be generated by the reaction of chlorine substituted aromatic compounds in sulfoxide in the presence of fluorine anion in fair yield. A likely mechanism was proposed.
A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP ...A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.展开更多
Aromatic oxazolines are versatile in organic synthesis as directing groups,ligands,and protected carboxylic acids.Developing efficient approaches to oxazoline from an aromatic C−H bond is more desirable compared to th...Aromatic oxazolines are versatile in organic synthesis as directing groups,ligands,and protected carboxylic acids.Developing efficient approaches to oxazoline from an aromatic C−H bond is more desirable compared to the established protocols from carboxylic acid and its equivalents.Herein,a simple and efficient aromatic C−H oxazolination with broad substrate scope is described.By employing this transformation as an enabling step,diversity-oriented synthesis of functionalized arenes and target-oriented synthesis of four drugs were accomplished.Mechanistic experiments suggest that this aromatic oxazolination is an electrophilic aromatic substitution.It is anticipated that this transformation will find applications in aromatic C−H functionalization with oxazoline either as a removable directing group or as a masked carboxylic acid.展开更多
The reactions of [Bt3NH][μ-CO)(μ-RS)Fe2(CO)6] (1a-d) (R=nPr,nBu,tBu, Ph) with p-MeC6H4C=CPh or m-NO2C6H4C=CPh were studied and products of the vinyl type (μ-σ,π-p-MeC6H4C=CHPh)(μ-RS)Fe2(CO)6 (2) and (μ-σ,π-ph...The reactions of [Bt3NH][μ-CO)(μ-RS)Fe2(CO)6] (1a-d) (R=nPr,nBu,tBu, Ph) with p-MeC6H4C=CPh or m-NO2C6H4C=CPh were studied and products of the vinyl type (μ-σ,π-p-MeC6H4C=CHPh)(μ-RS)Fe2(CO)6 (2) and (μ-σ,π-phC=CHC6H4Me-p) (μ-RS)Fe2(CO)6 (3) (R=nPr, nBu, tBu, Ph) were obtained. While the structures of all the compounds 2a-d and 3a-d were characterized by elemental analysis, IR,1H NMR and MS spectroscopies, the single-crystal structure of 2c(R=tBu) was determined by X-ray diffraction method. The X-ray dim-action result of 2c showed that the substituted vinyl ligand p-MeC6H4C=CHPh bridges the two uon centers, being σ-bonded to one metal through the olefinic carbon attached to p-MeC6H44 group, while π-bonded to the other via olefinic linkage; the Fe2(CO)6 and proton units are in a cis fashion and the tBu group is bonded to sulfur atom through an e-type of bond.展开更多
基金supported by the Foundation of Education Bureau,Sichuan Province(09ZB036)
文摘A molecular structural characterization （MSC） method called molecular vertexes correlative index （MVCI） was used to describe the structures of 30 substituted aromatic compounds. Through multiple linear regression （MLR） and stepwise multiple regression （SMR）, a quantitative structure-toxicity relationship （QSTR） model with 4 variables was obtained. The correlation coefficient （R） of the model was 0.9467. Through partial least-squares regression （PLS）, another QSTR model with 5 principal components was obtained. The correlation coefficient （R） of the model was 0.9518. Both models were evaluated by performing the cross-validation with the leave-one-out （LOO） procedure and the Cross-Validation （CV） correlation coefficients （Rcv） were 0.9208 and 0.9214, respectively. The results suggested good stability and predictability of the models, and the molecular vertexes correlative index could successfully describe the structures of the substituted aromatic compounds.
基金supported by the Natural Science Foundation of Fujian Province (D0710019)the Natural Science Foundation of Overseas Chinese Affairs Office of the State Council (06QZR09)
文摘With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity relationship（QSAR） models to predict the acute toxicity（-lgEC50） of substituted aromatic compounds to Photobacterium phosphoreum were established.Four molecular descriptors that appear in the MLR model,namely,the second order valence molecular connectivity index（2XV）,the energy of the highest occupied molecular orbital（EHOMO）,the logarithm of n-octyl alcohol/water partition coefficient（logKow） and the Connolly molecular area（MA）,were inputs of the ANN model.The root-mean-square error（RMSE） of the training and validation sets of the ANN model are 0.1359 and 0.2523,and the correlation coefficient（R） is 0.9810 and 0.8681,respectively.The leave-one-out（LOO） cross validated correlation coefficient（Q L2OO） of the MLR and ANN models is 0.6954 and 0.6708,respectively.The result showed that the two methods are complementary in the calculations.The regression method gave support to the neural network with physical explanation,and the neural network method gave a more accurate model for QSAR.In addition,some insights into the structural factors affecting the acute toxicity and toxicity mechanism of substituted aromatic compounds were discussed.
文摘Heteroatom-directed aromatic lithiation reactions used for the regiospecific synthesis of o-isopropyl substituted phenolic and benzyl alcoholic compounds are described.
基金supported by the National Natural Science Foundation of China(22275072 and 62105184)the Natural Science Foundation of Guangdong Province(2020A1515010622)+1 种基金the Project of Science and Technology of Guangzhou(2024A04J3712)the Teli Young Scholar Program of Beijing Institute of Technology.
文摘Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.
基金This work was supported by the National Natural Science Foundation of China(No.51979255).
文摘The knowledge of the existence,distribution and fate of polycyclic aromatic hydrocarbons(PAHs)and substituted polycyclic aromatic hydrocarbons(SPAHs)in wastewater treatment plants(WWTPs)was vital for reducing their concentrations entering the aquatic environment.The concentrations of 13 SPAHs and 16 PAHs were all determined in a WWTP with styrene butadiene rubber(SBR)in partnership with the moving bed biofilm reactor(MBBR)process.SPAHs presented a higher concentration lever than PAHs in nearly all samples.The total removal efficiencies of PAHs and SPAHs ranged from 64.0%to 71.36%and 78.4%to 79.7%,respectively.The total yearly loads of PAHs(43.0 kg)and SPAHs(73.0 kg)were mainly reduced by the primary and SBR/MBBR biological treatment stages.The tertiary treatment stage had a minor contribution to target compounds removal.According to a synthesis and improvement fate model,we found that the dominant processes changed as the chemical octanol water partition coefficient(K_(ow))increased.But the seasonal variations of experimental removal efficiencies were more obvious than that of predicted data.In the primary sedimentation tank,dissolution in the aqueous phase and sorption to sludge/particulate matter were controlling processes for the removal of PAHs and SPAHs.The sorption to sludge and biodegradation were the principal removal mechanisms during the SBR/MBBR biological treatment process.The contribution of volatilization to removal was always insignificant.Furthermore,the basic physicochemical properties and operating parameters influenced the fate of PAHs and SPAHs in the WWTP.
基金Financial support from National Key R&D Program of China(No.2023YFA1507203)National Natural Science Foundation of China(Nos.22371149,22188101)+2 种基金the Fundamental Research Funds for the Central Universities(No.63224098)Frontiers Science Center for New Organic Matter,Nankai University(No.63181206)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformation utilizes commercially available reagents,cheap electrodes,and simple equipment.Diverse aryl nitriles were successfully obtained in a direct and efficient way with broad substrate scope,excellent functional group tolerance,and selective C-O bond cleavage.Furthermore,late-stage modification of biorelevant compounds and gram-scale synthesis highlighted the potential application of the strategy.Mechanistic investigations suggest that the arene cation radical was considered as the key intermediate for the transformation,and undergoing the followed S_(N)Ar process.
文摘The electrophilic aromatic substitution reactions have been studied by using the con- cept of pseudo orbital proposed by authors,Because the unoccupied orbitals of electrophilic reagents have been.taken into account,the present results are better than ones given by superdelocalizability,S,.
文摘It is experimentally found that different renction courses exist when mtrite ion reacts with nitrobenzenes with different electron withdrawing groups. when it is substituted with strong electron withdrawing groups. self-condensation in aprotic polar solvent occurs to give symmnetrical disubstituted diphenyl ethers. However. when it is substituted with moderate electron withdrawing groups, no diphenyl ethers are obtained under the same conditions, instead, corresponding carboxylates are yielded. As a result. the applicability of this reaction is distinctly clarified
基金supported by the National Natural Science Foundation for Young Scholar of China(No.21276042)the National Science and Technology Pillar Program(No. 2013BAF08B06)Jiaogai Foundation of DUT(No.JGXM201224)
文摘An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0-5 ℃, solvent： water） within a short reaction time （1 h）. A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.
基金financial support from Program for Innovative Research Team in IMPLAD(PIRTI)the Open Funding Project of the State Key Laboratory of Bioactive Substance and Function of Natural Medicines+1 种基金PUMC Youth Fund and the Fundamental Research Funds for the Central Universitiesthe Chinese National S&T Special Project on Major New Drug Innovation(Nos.2013ZX09508104,2011ZX09307-002-01)
文摘Chaetoxanthone D（1）, a new tetrahydropyran-substituted xanthone originated from polyketide pathway, together with the four known natural products chaetoxanthone C（2）, alternariol methyl ether（3）, alternariol（4） and 2,5-dimethyl-7-hydroxychromone（5） was isolated from a strain of Chaetomium murorum. The structures of these compounds were elucidated based on extensive spectroscopic analyses. The absolute configurations of 1 and 2 were determined by using quantum chemical electronic circular dichroism（ECD） calculations.
文摘A highly efficient copolymer (methacrylic acid - co - styrene - divinylbenzene) in situ making high-performance liquid chromatographic column was prepared and evaluated. The column efficiency calculated in terms of height equivalent to a theoretical plate was 25 mu m and rapid separations of small molecules such as substituted aromatic hydrocarbons and aromatic acids were achieved within five minutes.
基金supported by University of Colorado Boulder and K. C. Wong Education Foundationfinancial support by the Koch Graduate fellowship。
文摘We report a series of highly stable metallophthalocyanine-based covalent organic frameworks(MPc-dxCOFs) linked by robust 1,4-dioxin bonds constructed through nucleophilic aromatic substitution(SNAr)reaction. The chemical structures and crystallinity of the COFs largely remain unchanged even after treating with boiling water(90°C), concentrated acids(12 mol/L HCl) or bases(12 mol/L Na OH), oxidizing(30% H_(2)O_(2)) or reducing agents(1 mol/L NaBH;) for three days due to their stable M-Pc building blocks and resilient dioxin linkers. With metallated phthalocyanine active sites regularly arranged in the stable framework structures, MPc-dx-COFs can be directly used as efficient electrocatalysts for the oxygen reduction reaction(ORR) without pyrolysis treatment that has commonly been used in previous studies.
基金financial support by the National Natural Science Foundation of China (No.U1532135)
文摘An efficient and practical synthetic protocol to synthesize nonsymmetrical aryl thioethers by nucleophilic aromatic substitution(S_NAr)reaction of nitroarenes by thiols with potassium phosphate as the catalyst is described.Various moderate to strong electron-withdrawing functional groups are tolerated by the system to provide thioethers in a good to excellent yields.We also showed that the present method allows access to 3 drug examples in a short reaction time.Finally,mechanistic studies suggest that the reaction may form the classic Meisenheimer complex through a two-step additionelimination mechanism.
基金the National Natural Science Foundation of China (No.21172023)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and STD of Jiangsu Province for their financial supports
文摘A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtained in moderate to high isolated yields（up to 82%） with good stereoselevtivities（up to 15：1） in the presence of 5 mol% of Cu（OAc）2at room temperature.
基金the National Natural Science Foundation of China(No.20902070)Natural Science Foundation of Zhejiang Province(No.Y4100579)Qianjiang Talents Program of Zhejiang Province(No.QJD0902004) for financial supports
文摘Tetrabutylammonium fluoride （TBAF） effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane （PhSTMS） under mild and base-free neutral conditions at room temperature, providing a practical and efficient synthesis of useful unsymmetrical diaryl thioethers. Nitroarenes bearing ortho- and para-positioned electron-withdrawing groups are the most reactive substrates, indicating that this reaction most possibly proceeded via the nucleophilic aromatic substitution （SNAr） mechanism.
文摘The 1-azido-2-chloro-4-nitrobenzene was prepared by nucleophilic substitution between 2-chloro-4-nitro-1-(trifluoromethylsulfinyl)benzene and sodium azide, and its structure was characterized by NMR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n, Z = 8 and Mr = 198.57. A cultivation process of the single crystal of unstable aryl azide was provided. The group of trifluoromethyl sulfinyl was found for the first time to be a new excellent leaving group of aromatic nucleophilic substitution reactions.
基金Hui LOU thanks the Natural Science Foundation of Zhejiang Province (No.299024).
文摘Unsymmetrical sulfides can be generated by the reaction of chlorine substituted aromatic compounds in sulfoxide in the presence of fluorine anion in fair yield. A likely mechanism was proposed.
文摘A new electrophilic polymer, 2,4-dinitrophenyl ether of polyvinyl alcohol (PVA-DNP), having a degree of substitution of 0.5 was prepared from polyvinyl alcohol (PVA) and 1-fluro-2,4-dinitrobenzene (DNFB). The PVA-DNP polymer was characterized by NMR, IR, and UV-visible spectroscopy. The reaction of PVA-DNP with sodium methoxide was followed by NMR and UV-visible spectroscopy. Evidence of polymer bound spirocyclic SIGMA complex, C-1 and C-3 polymer bound DNP-methoxy SIGMA complexes and the formation and C-1 methoxy complex of 2,4-dinitroanisole was observed.
基金the Fundamental Research Funds for the Central Universities(22qntd2306)Guangzhou Municipal Science and Technology Bureau(202201011151)the National Natural Science Foundation of China(22201311).
文摘Aromatic oxazolines are versatile in organic synthesis as directing groups,ligands,and protected carboxylic acids.Developing efficient approaches to oxazoline from an aromatic C−H bond is more desirable compared to the established protocols from carboxylic acid and its equivalents.Herein,a simple and efficient aromatic C−H oxazolination with broad substrate scope is described.By employing this transformation as an enabling step,diversity-oriented synthesis of functionalized arenes and target-oriented synthesis of four drugs were accomplished.Mechanistic experiments suggest that this aromatic oxazolination is an electrophilic aromatic substitution.It is anticipated that this transformation will find applications in aromatic C−H functionalization with oxazoline either as a removable directing group or as a masked carboxylic acid.
基金supported by the National Natural Science Foundation of China.
文摘The reactions of [Bt3NH][μ-CO)(μ-RS)Fe2(CO)6] (1a-d) (R=nPr,nBu,tBu, Ph) with p-MeC6H4C=CPh or m-NO2C6H4C=CPh were studied and products of the vinyl type (μ-σ,π-p-MeC6H4C=CHPh)(μ-RS)Fe2(CO)6 (2) and (μ-σ,π-phC=CHC6H4Me-p) (μ-RS)Fe2(CO)6 (3) (R=nPr, nBu, tBu, Ph) were obtained. While the structures of all the compounds 2a-d and 3a-d were characterized by elemental analysis, IR,1H NMR and MS spectroscopies, the single-crystal structure of 2c(R=tBu) was determined by X-ray diffraction method. The X-ray dim-action result of 2c showed that the substituted vinyl ligand p-MeC6H4C=CHPh bridges the two uon centers, being σ-bonded to one metal through the olefinic carbon attached to p-MeC6H44 group, while π-bonded to the other via olefinic linkage; the Fe2(CO)6 and proton units are in a cis fashion and the tBu group is bonded to sulfur atom through an e-type of bond.
