A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good function...A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good functional group compatibility.The application experiments including gram-scale synthesis and derivatization of the product are performed to illustrate the synthetic potential.This method offers mild conditions and efficient access to polysubstituted pyrroles.展开更多
Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by p...Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes, Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2, 4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.展开更多
This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4＇- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropylox...This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4＇- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy chain.The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure.All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain（R = C_（18）H_（37））,exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.展开更多
Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and ...Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and dichloromethane is described. The reaction has intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes and a possible mechanism is also suggested.展开更多
Octanol/water partition coefficient （Kow） is a crucial property for evaluating the environmental behavior and fate of organic compound. Herein, some quantitative structure-property relationship （QSPR） studies were...Octanol/water partition coefficient （Kow） is a crucial property for evaluating the environmental behavior and fate of organic compound. Herein, some quantitative structure-property relationship （QSPR） studies were performed to estimate and predict the lgK ow of substituted anilines. 2D method （multiple linear regression, MLR） and 3D method （comparative molecular field analysis, CoMFA） were applied in this study. Successful 2D and 3D models yielded the correlation coefficient （R2） values of 0.981 and 0.966 and the Leave-One-Out （LOO） cross-validated correlation coefficient （q2） values of 0.933 and 0.820, respectively. The developed models have a highly predictive ability in both internal and external validation. In addition, the results were interpreted in terms of physical and chemical meanings of descriptors and field contribution maps. It showed that the steric and electrostatic properties are the primary factors that govern the lgK ow of substituted anilines. The information obtained from the QSPR models would be helpful to the interpretation of structural features pertinent to the lgK ow of substituted anilines, which may be helpful in estimating the organic compounds＇ potential harm to the environment.展开更多
We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidaz...We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidazole as activator.展开更多
Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides....Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.展开更多
While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic a...While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono- and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).展开更多
Six-membered N-heterocycles,such as 2-pyridones,are crucial in bioactive compounds and prevalent in natural products and pharmaceuticals,necessitating innovative synthesis approaches.Traditional methods,typically reli...Six-membered N-heterocycles,such as 2-pyridones,are crucial in bioactive compounds and prevalent in natural products and pharmaceuticals,necessitating innovative synthesis approaches.Traditional methods,typically reliant on the transitionmetal-catalyzed direct cyclization of alkynes,face limitations in product complexity.This study introduces a[1+2+3]annulation strategy for synthesizing 2-pyridones,employing anilines and CF_(3)-ynones through a base-promoted metal-free catalytic system.This method offers a more streamlined approach to generating polysubstituted 2-pyridones,demonstrating enhanced functional group compatibility across substrates compared with existing transformations.The anilines’adjacent dialkyl amino groups significantly contribute to the reaction,serving as both proton reservoirs and directing groups,facilitating the formation of 2-pyridones.This reaction involves a ring closure/opening sequence,followed by aza-6π-electrocyclization and a C−C bond cleavage-driven aromatization process.The method’s synthetic utility is further validated by its applicability in subsequent transformations,marking an advancement in the synthesis of complex N-heterocyclic compounds.展开更多
Amines are among the most fundamental motifs in chemical synthesis,and the introduction of amine building blocks via selective C-C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons t...Amines are among the most fundamental motifs in chemical synthesis,and the introduction of amine building blocks via selective C-C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification.Herein,we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents,which are easily prepared from hydroxylamine.Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions.Good compatibility and valuable applications of the transformation were also displayed.展开更多
Active free radicals formed by the electrooxidation of substituted anilines RC_6H_4NH_3 (R=H, p-Br, p-Cl, p-I, p-Me, p-COOH, p-MeCO, p-NO_2, m-CO_2H, and m-Cl) are trapped by spin trap 2-methyl-2-nitroso propane (MNP)...Active free radicals formed by the electrooxidation of substituted anilines RC_6H_4NH_3 (R=H, p-Br, p-Cl, p-I, p-Me, p-COOH, p-MeCO, p-NO_2, m-CO_2H, and m-Cl) are trapped by spin trap 2-methyl-2-nitroso propane (MNP). A multiple ESR signal of the solution containing electrolytic aniline and MNP is identified with the spin adduct of MNP and radical cation 1 by theore- tical simulation of observed spectrum. Furthermore, ESR spectra of para- or meta-substituted anilines give a reasonable explanation about spin adducts of MNP and the cation 2 or 3 by the same method.展开更多
A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines i...A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design （OAD） with OA25（54） matrix. Analysis of variance （ANOVA） and percent contribution （PC） were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity （r2 〉 0.99） over the studied range （50-1000 ng g-l） for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections （LODs） and limit of quantitations （LOQs） ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.展开更多
Nitroanilines are important building blocks in pharmaceuticals,materials and dyes.Nitration methods for anilines under mild conditions are highly desired.Herein,we report a photochemical method for the nitration of an...Nitroanilines are important building blocks in pharmaceuticals,materials and dyes.Nitration methods for anilines under mild conditions are highly desired.Herein,we report a photochemical method for the nitration of anilines bearing various protecting groups by 5-methyl-1,4-dinitroimidazole as a new type of nitro source.This method is light-controlled and proceeds under mild reaction conditions with high efficiency.Fmoc-,Ts-and alkyl-protected anilines are all well nitrated with good functional group tolerance.展开更多
An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under...An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.展开更多
Rhodium-catalysed regioselective redox-neutral[3+3]-cycloaddition of anilines with CF_(3)-ynones was achieved via a traceless directing group strategy.A variety of substituted 2-trifluromethylquinoline compounds were ...Rhodium-catalysed regioselective redox-neutral[3+3]-cycloaddition of anilines with CF_(3)-ynones was achieved via a traceless directing group strategy.A variety of substituted 2-trifluromethylquinoline compounds were obtained in good to excellent yields,which exhibited favorable blue emission properties.展开更多
The reduction of nitrobenzene to aniline is very important for both pollution control and chemical synthesis.Nevertheless,difficulties still remain in developing a catalytic system having high efficiency and selectivi...The reduction of nitrobenzene to aniline is very important for both pollution control and chemical synthesis.Nevertheless,difficulties still remain in developing a catalytic system having high efficiency and selectivity for the production of aniline.Herein,it was found that PdO nanoparticles highly dispersed on TiO_(2)support(PdO/TiO_(2))functioned as a highly efficient catalyst for the reduction of nitrobenzene in the presence of NaBH4.Under favorable conditions,95%of the added nitrobenzene(1 mmol/L)was reduced within 1 min with an ultra-low apparent activation energy of 10.8 kJ/mol by using 0.5%PdO/TiO_(2)as catalysts and 2 mmol/L of NaBH4 as reductants,and the selectivity to aniline even reached up to 98%.The active hydrogen specieswere perceived as dominant species during the hydrogenation of nitrobenzene by the results of isotope labeling experiments and ESR spectroscopic.A mechanismwas proposed as follows:PdO activates the nitro groups and leads to in-situ generation of Pd,and the generated Pd acts as the reduction sites to produce active hydrogen species.In this catalytic system,nitrobenzene prefers to be adsorbed on the PdO nanoparticles of the PdO/TiO_(2)composite.Subsequently,the addition of NaBH_(4) results in in-situ generation of a Pd/PdO/TiO_(2)composite from the PdO/TiO_(2)composite,and the Pd nanoclusters would activate NaBH_(4) to generate active hydrogen species to attack the adsorbed nitro groups.This work will open up a new approach for the catalytic transfer hydrogenation of nitrobenzene to aniline in green chemistry.展开更多
2,6-Diisopropylaniline reacts with an open-cage fullerene derivative with a 11-membered orifice and forms an open-cage derivative containing one imino group on the rim of the expanded orifice.Further treatment with Le...2,6-Diisopropylaniline reacts with an open-cage fullerene derivative with a 11-membered orifice and forms an open-cage derivative containing one imino group on the rim of the expanded orifice.Further treatment with Lewis acids leads to open-cage fullerenes with an 18-membered orifice.Instead of the direct addition process observed before for less bulky anilines,an electron transfer process takes place in the initial step in the present reaction with bulky 2,6-diisopropylaniline.As a result,the chemo-selectivity is completely different affording the mono imino open-cage derivative selectively.展开更多
As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of ...As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of aniline in HNO_(3)solution was successfully achieved at room temperature without the use of chemical oxidants.Through the analysis of the radiation chemical reactions of inorganic acids and nitrate salt solutions,the characterization of the intermediate free radicals in the irradiated systems,and the influence of the pH of the solutions on the polymerization activity and product morphologies,the radiation-induced polymerization mechanism of aniline is discussed in detail and proposed.Only at a condition of[HNO_(3)]>[aniline],i.e.,pH<2.5,PANI can be successfully obtained underγ-ray radiation.The polymerization begins with the oxidation of aniline cations to aniline cation radicals by·NO_(3)generated by radiolysis reactions,and undergoes repeated three steps of monomer free radical recombination,deprotonation,and oxidation reaction of·NO_(3),thus forming a PANI macromolecule.In addition to the polymerization reaction,the aniline units are protonated and oxidized because of the strongly acidity and oxidation of the reaction system under γ-ray irradiation,which means that the molecular chain structure of the radiation-synthesized PANI can be regulated by pH,nitrate concentration,and irradiation conditions.Radiation-synthesized PANI has a moderate protonation and oxidation state,which can be used for the preparation of PANI supercapacitors with better electrochemical properties than those prepared by chemical oxidation under the same conditions.This work presents a new radiation-synthesis method and polymerization mechanism of PANI,which not only expands the application of radiation technique in the field of polymer synthesis,but also provides a new idea for the structural regulation and electrochemical property optimization of PANI.展开更多
Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method.Scanning electron microscopy,X-ray diffraction,and electroche...Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method.Scanning electron microscopy,X-ray diffraction,and electrochemical measurements were used to characterize its morphology,crystal structure,and electrochemical properties.Removal of aniline by the Ti/TiOxHy/Sb-SnO2electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand（COD）analysis under different conditions,including current densities,initial concentrations of aniline,pH values,concentrations of chloride ions,and types of reactor.It was found that a higher current density,a lower initial concentration of aniline,an acidic solution,the presence of chloride ions（0.2wt%NaCl）,and a three-dimensional（3D） reactor promoted the removal efficiency of aniline.Electrochemical degradation of aniline followed pseudo-first-order kinetics.The aniline（200 mL of 100mg·L-（-1）） and COD removal efficiencies reached 100%and 73.5%,respectively,at a current density of 20 mA·cm-（-2）,pH of 7.0,and supporting electrolyte of 0.5 wt%Na2SO4 after 2 h electrolysis in a 3D reactor.These results show that aniline can be significantly removed on the Ti/TiOxHy/Sb-SnO2electrode,which provides an efficient way for elimination of aniline from aqueous solution.展开更多
文摘A palladium-catalyzed three-component annulation of anilines,alkyne esters,and alkynes has been developed for the synthesis of polysubstituted pyrroles.The protocol demonstrates broad substrate scope and good functional group compatibility.The application experiments including gram-scale synthesis and derivatization of the product are performed to illustrate the synthetic potential.This method offers mild conditions and efficient access to polysubstituted pyrroles.
基金This work was supported by the National Natural Science Foundation of China (No. 50379012)Program for New Century Excellent Talents in University (No. 05-0481).
文摘Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes, Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2, 4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.
基金Universiti Sains Malaysia for USM RU(No.1001/PKIMIA/811159) and the research facilities
文摘This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4＇- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy chain.The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure.All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain（R = C_（18）H_（37））,exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.
文摘Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and dichloromethane is described. The reaction has intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes and a possible mechanism is also suggested.
基金Supported by the NNSF of China (No. 20737001)Program for Environment Protection in Jiangsu Province (201140)
文摘Octanol/water partition coefficient （Kow） is a crucial property for evaluating the environmental behavior and fate of organic compound. Herein, some quantitative structure-property relationship （QSPR） studies were performed to estimate and predict the lgK ow of substituted anilines. 2D method （multiple linear regression, MLR） and 3D method （comparative molecular field analysis, CoMFA） were applied in this study. Successful 2D and 3D models yielded the correlation coefficient （R2） values of 0.981 and 0.966 and the Leave-One-Out （LOO） cross-validated correlation coefficient （q2） values of 0.933 and 0.820, respectively. The developed models have a highly predictive ability in both internal and external validation. In addition, the results were interpreted in terms of physical and chemical meanings of descriptors and field contribution maps. It showed that the steric and electrostatic properties are the primary factors that govern the lgK ow of substituted anilines. The information obtained from the QSPR models would be helpful to the interpretation of structural features pertinent to the lgK ow of substituted anilines, which may be helpful in estimating the organic compounds＇ potential harm to the environment.
文摘We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidazole as activator.
基金partial financial support from the Ministry of Science and Technology of China (No. 2016YFE0132600)Zhengzhou University
文摘Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.
文摘While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono- and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).
基金the Fundamental Research Funds for the Central Universities(buctrc202408)National Natural Science Foundation of China(21801061)+1 种基金Natural Science Foundation of Henan(212300410119)Henan University,and Beijing University of Chemical Technology.
文摘Six-membered N-heterocycles,such as 2-pyridones,are crucial in bioactive compounds and prevalent in natural products and pharmaceuticals,necessitating innovative synthesis approaches.Traditional methods,typically reliant on the transitionmetal-catalyzed direct cyclization of alkynes,face limitations in product complexity.This study introduces a[1+2+3]annulation strategy for synthesizing 2-pyridones,employing anilines and CF_(3)-ynones through a base-promoted metal-free catalytic system.This method offers a more streamlined approach to generating polysubstituted 2-pyridones,demonstrating enhanced functional group compatibility across substrates compared with existing transformations.The anilines’adjacent dialkyl amino groups significantly contribute to the reaction,serving as both proton reservoirs and directing groups,facilitating the formation of 2-pyridones.This reaction involves a ring closure/opening sequence,followed by aza-6π-electrocyclization and a C−C bond cleavage-driven aromatization process.The method’s synthetic utility is further validated by its applicability in subsequent transformations,marking an advancement in the synthesis of complex N-heterocyclic compounds.
基金Financial support from the National Natural Science Foundation of China(Nos.21772002,21901010,and 21901012)the Open Research Fund of State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)is greatly appreciated.
文摘Amines are among the most fundamental motifs in chemical synthesis,and the introduction of amine building blocks via selective C-C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification.Herein,we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents,which are easily prepared from hydroxylamine.Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions.Good compatibility and valuable applications of the transformation were also displayed.
文摘Active free radicals formed by the electrooxidation of substituted anilines RC_6H_4NH_3 (R=H, p-Br, p-Cl, p-I, p-Me, p-COOH, p-MeCO, p-NO_2, m-CO_2H, and m-Cl) are trapped by spin trap 2-methyl-2-nitroso propane (MNP). A multiple ESR signal of the solution containing electrolytic aniline and MNP is identified with the spin adduct of MNP and radical cation 1 by theore- tical simulation of observed spectrum. Furthermore, ESR spectra of para- or meta-substituted anilines give a reasonable explanation about spin adducts of MNP and the cation 2 or 3 by the same method.
基金supported by the National Natural Science Foundation of China (20905073 & 20975105)
文摘A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design （OAD） with OA25（54） matrix. Analysis of variance （ANOVA） and percent contribution （PC） were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity （r2 〉 0.99） over the studied range （50-1000 ng g-l） for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections （LODs） and limit of quantitations （LOQs） ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.
基金supported by NSF of China(Grant 21922703 and 91953112 to H.W.)the Natural Science Foundation of Jiangsu Province(Grant BK20190004 and BK20202004)National Key R&D Program of China(2019YFA0905800).
文摘Nitroanilines are important building blocks in pharmaceuticals,materials and dyes.Nitration methods for anilines under mild conditions are highly desired.Herein,we report a photochemical method for the nitration of anilines bearing various protecting groups by 5-methyl-1,4-dinitroimidazole as a new type of nitro source.This method is light-controlled and proceeds under mild reaction conditions with high efficiency.Fmoc-,Ts-and alkyl-protected anilines are all well nitrated with good functional group tolerance.
基金Project supported by the National Natural Science Foundation of China （No. 20672035） and Key Laboratory of 0rganofluorine Chemistry, Shanghai Institute of 0rganic Chemistry, Chinese Academy of Sciences.
文摘An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.
基金supported by NSF of China(no.21602064 and 22004041)the Science and Technology Project of Quanzhou City(2018C073R)the Instrumental Analysis Center of Huaqiao University.
文摘Rhodium-catalysed regioselective redox-neutral[3+3]-cycloaddition of anilines with CF_(3)-ynones was achieved via a traceless directing group strategy.A variety of substituted 2-trifluromethylquinoline compounds were obtained in good to excellent yields,which exhibited favorable blue emission properties.
基金supported by the National Natural Science Foundation of China (No.22076052)the Natural Science Foundation of Hubei Province (Nos.2021CFB535 and 2020CFB437)+2 种基金the Knowledge Innovation Program of Wuhan-Basic Research (No.SZY23005)the Fundamental Research Funds for the Central Universities,South-Central Minzu University (No.CZQ22002)Wuhan University (No.2042020kf0036).
文摘The reduction of nitrobenzene to aniline is very important for both pollution control and chemical synthesis.Nevertheless,difficulties still remain in developing a catalytic system having high efficiency and selectivity for the production of aniline.Herein,it was found that PdO nanoparticles highly dispersed on TiO_(2)support(PdO/TiO_(2))functioned as a highly efficient catalyst for the reduction of nitrobenzene in the presence of NaBH4.Under favorable conditions,95%of the added nitrobenzene(1 mmol/L)was reduced within 1 min with an ultra-low apparent activation energy of 10.8 kJ/mol by using 0.5%PdO/TiO_(2)as catalysts and 2 mmol/L of NaBH4 as reductants,and the selectivity to aniline even reached up to 98%.The active hydrogen specieswere perceived as dominant species during the hydrogenation of nitrobenzene by the results of isotope labeling experiments and ESR spectroscopic.A mechanismwas proposed as follows:PdO activates the nitro groups and leads to in-situ generation of Pd,and the generated Pd acts as the reduction sites to produce active hydrogen species.In this catalytic system,nitrobenzene prefers to be adsorbed on the PdO nanoparticles of the PdO/TiO_(2)composite.Subsequently,the addition of NaBH_(4) results in in-situ generation of a Pd/PdO/TiO_(2)composite from the PdO/TiO_(2)composite,and the Pd nanoclusters would activate NaBH_(4) to generate active hydrogen species to attack the adsorbed nitro groups.This work will open up a new approach for the catalytic transfer hydrogenation of nitrobenzene to aniline in green chemistry.
基金supported by Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-201904)National Natural Science Foundation of China(NSFC,Nos.22171009,and 22261039)。
文摘2,6-Diisopropylaniline reacts with an open-cage fullerene derivative with a 11-membered orifice and forms an open-cage derivative containing one imino group on the rim of the expanded orifice.Further treatment with Lewis acids leads to open-cage fullerenes with an 18-membered orifice.Instead of the direct addition process observed before for less bulky anilines,an electron transfer process takes place in the initial step in the present reaction with bulky 2,6-diisopropylaniline.As a result,the chemo-selectivity is completely different affording the mono imino open-cage derivative selectively.
基金financially supported by the National Natural Science Foundation of China(Nos.51973205 and 51773189)the Fundamental Research Funds for the Central Universities(Nos.WK9110000066,WK345000005 and WK345000006).
文摘As a highly promising conductive polymer material,the synthesis method,structure regulation,and performance improvement of polyaniline(PANI)are hot research topics.In this work,the radiation-induced polymerization of aniline in HNO_(3)solution was successfully achieved at room temperature without the use of chemical oxidants.Through the analysis of the radiation chemical reactions of inorganic acids and nitrate salt solutions,the characterization of the intermediate free radicals in the irradiated systems,and the influence of the pH of the solutions on the polymerization activity and product morphologies,the radiation-induced polymerization mechanism of aniline is discussed in detail and proposed.Only at a condition of[HNO_(3)]>[aniline],i.e.,pH<2.5,PANI can be successfully obtained underγ-ray radiation.The polymerization begins with the oxidation of aniline cations to aniline cation radicals by·NO_(3)generated by radiolysis reactions,and undergoes repeated three steps of monomer free radical recombination,deprotonation,and oxidation reaction of·NO_(3),thus forming a PANI macromolecule.In addition to the polymerization reaction,the aniline units are protonated and oxidized because of the strongly acidity and oxidation of the reaction system under γ-ray irradiation,which means that the molecular chain structure of the radiation-synthesized PANI can be regulated by pH,nitrate concentration,and irradiation conditions.Radiation-synthesized PANI has a moderate protonation and oxidation state,which can be used for the preparation of PANI supercapacitors with better electrochemical properties than those prepared by chemical oxidation under the same conditions.This work presents a new radiation-synthesis method and polymerization mechanism of PANI,which not only expands the application of radiation technique in the field of polymer synthesis,but also provides a new idea for the structural regulation and electrochemical property optimization of PANI.
基金supported by the National Natural Science Foundation of China(21507104)the Fundamental Research Funds for the Central Universities of China
文摘Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method.Scanning electron microscopy,X-ray diffraction,and electrochemical measurements were used to characterize its morphology,crystal structure,and electrochemical properties.Removal of aniline by the Ti/TiOxHy/Sb-SnO2electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand（COD）analysis under different conditions,including current densities,initial concentrations of aniline,pH values,concentrations of chloride ions,and types of reactor.It was found that a higher current density,a lower initial concentration of aniline,an acidic solution,the presence of chloride ions（0.2wt%NaCl）,and a three-dimensional（3D） reactor promoted the removal efficiency of aniline.Electrochemical degradation of aniline followed pseudo-first-order kinetics.The aniline（200 mL of 100mg·L-（-1）） and COD removal efficiencies reached 100%and 73.5%,respectively,at a current density of 20 mA·cm-（-2）,pH of 7.0,and supporting electrolyte of 0.5 wt%Na2SO4 after 2 h electrolysis in a 3D reactor.These results show that aniline can be significantly removed on the Ti/TiOxHy/Sb-SnO2electrode,which provides an efficient way for elimination of aniline from aqueous solution.
