Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition re...Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition reactions in water at room temperature. The mechanism responsible for the moder‐ate activity and enantioselectivity of the β‐cyclodextrin derivatives was explored using nuclear magnetic resonance spectroscopy, namely 2D 1H rotating‐frame overhauser effect spectroscopy （ROESY）, ultraviolet absorption spectroscopy, and quantum chemical calculations, which provide a useful technique for investigating the formation of inclusion complexes. The effects of the pH of the reaction medium, theβ‐cyclodextrin derivative dosage, the structure of the modifying amino group, and various substrates on the yield and enantioselectivity were investigated. The results indicated that these factors had an important effect on the enantiomeric excess （ee） in the reaction system. Experiments using a competitor for inclusion complex formation showed that a hydrophobic cavity is necessary for enantioselective Michael addition. A comparison of the reactions using 4‐nitro‐β‐nitrostyrene and 2‐nitro‐β‐nitrostyrene showed that steric hindrance improved the enan‐tioselectivity. This was verified by the optimized geometries obtained from quantum chemical cal‐culations. An ee of 71%was obtained in the asymmetric Michael addition of cyclohexanone and 2‐nitro‐β‐nitrostyrene, using （S）‐2‐aminomethylpyrrolidine‐modified β‐CD as the catalyst, in an aqueous buffer solution, i.e., CH3COONa‐HCl （pH 7.5）.展开更多
Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their...The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their distinct sensing mechanisms and experimental phenomena. The time-dependent density functional theory has been applied to investigate the ground states and the first singlet excited electronic states of the sensor as well as their possible Michael reaction products with cyanide, with a view to monitoring their geometries and photophysieal properties. The theoretical study indicates that the protic water solvent could lead to final Michael addition product of sensor a in the ground state, while the aprotic acetonitrile solvent could lead to carbanion as the final product of sensor b. Furthermore, the Michael reaction product of sensor a has been proved to have a torsion structure in its first singlet excited state. Correspondingly, sensor b also has a torsion structure around the nitrovinyl moiety in its first singlet excited state, while not in its carbanion structure. This could explain the observed strong fluorescence for sensor a and the quenching fluorescence for the sensor b upon the addition of the cyanide anions in the relevant sensing mechanisms.展开更多
A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A rang...A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A range of chalcones and nitroalkenes together with active methylene compounds have been converted smoothly to the corresponding products in high yields.展开更多
Michael addition of active methylene compounds to α,β-unsaturated carboxylic esters and nitriles was effectively catalyzed by a basic ionic liquid, 1-butyl-3-methylimidazolium acetate（[Bmim]OAc）. The his-addition ...Michael addition of active methylene compounds to α,β-unsaturated carboxylic esters and nitriles was effectively catalyzed by a basic ionic liquid, 1-butyl-3-methylimidazolium acetate（[Bmim]OAc）. The his-addition products were selectively obtained in high yields under mild reaction conditions.展开更多
Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
An efficient Michael addition of indoles to unsaturated enones, such as chalcones and β-nitrostyrenes, was achieved in the presence of a catalytic amount of nitrosonium tetrafluoroborate in ethyl ether. 2007 Long M...An efficient Michael addition of indoles to unsaturated enones, such as chalcones and β-nitrostyrenes, was achieved in the presence of a catalytic amount of nitrosonium tetrafluoroborate in ethyl ether. 2007 Long Min Wu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitro...A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitromethane, and active methylene compounds were converted smoothly to the corresponding products in high yields. The simple procedure, very mild conditions, high yields, and reuse of the IL without any loss of catalytic activity make this protocol considerably attractive for academic researches and practical applications.展开更多
Michael addition of the chiral alpha,beta -unsaturated ester 2 with furyl lithium proceeded in syn manner with excellent diastereoselectivity. The diastereoselectivity was not affected by the configuration of the doub...Michael addition of the chiral alpha,beta -unsaturated ester 2 with furyl lithium proceeded in syn manner with excellent diastereoselectivity. The diastereoselectivity was not affected by the configuration of the double bond in 2.展开更多
C-H bond can undergo vicarious Michael addition reaction （VMA） with doubleactivated double bond in the absence of strong base and catalyst under mild conditions. Intramolecular H-bonding, electron-withdrawing induct...C-H bond can undergo vicarious Michael addition reaction （VMA） with doubleactivated double bond in the absence of strong base and catalyst under mild conditions. Intramolecular H-bonding, electron-withdrawing inductive effect, and steric hindrance at aposition of nucleophile facilitates C-H addition over N-H addition. By using VMA, high branching multiplicity, novel branching pattern, controllable density and distribution of functional groups can be envisioned for novel dendrimer synthesis.展开更多
A Zn/NH4Cl system was exploited at room temperature to promote the Michael addition reaction of various primary and secondary amines with α,β-unsaturated esters,nitriles,amides,and ketones to give the corresponding ...A Zn/NH4Cl system was exploited at room temperature to promote the Michael addition reaction of various primary and secondary amines with α,β-unsaturated esters,nitriles,amides,and ketones to give the corresponding saturated amines under the mild condition in high yield.展开更多
Promoted by SmI3 β -diketones， β-ketoesters and α -cyano esters were added to α,β -unsaturated esters to form δ-carbonyl esters in mild conditions in moderate to good yields.
An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temp...An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temperature.展开更多
It is crucial to adapt the processing of forest bio-resources into biochemicals and bio-based ad-vanced materials in order to transform the current economic climate into a greener economy.Tall oil,as a by-product of t...It is crucial to adapt the processing of forest bio-resources into biochemicals and bio-based ad-vanced materials in order to transform the current economic climate into a greener economy.Tall oil,as a by-product of the Kraft process of wood pulp manufacture,is a promising resource for the extraction of various value-added products.Tall oil fatty acids-based multifunctional Michael acceptor acrylates were developed.The suitability of developed acrylates for polymerization with tall oil fatty acids-based Michael donor acetoacetates to form a highly cross-linked polymer ma-terial via the Michael addition was investigated.With this novel strategy,valuable chemicals and innovative polymer materials can be produced from tall oil in an entirely new way,making a significant contribution to the development of a forest-based bioeconomy.Two different tall oil-based acrylates were successfully synthesized and characterized.Synthesized acrylates were successfully used in the synthesis of bio-based thermoset polymers.Obtained polymers had a wide variety of mechanical and thermal properties(glass transition temperature from-12.1 to 29.6°C by dynamic mechanical analysis,Young’s modulus from 15 to 1760 MPa,and stress at break from 0.9 to 16.1 MPa).Gel permeation chromatography,Fourier-transform infrared(FT-IR)spectroscopy,matrix-assisted laser desorption/ionization-time of flight mass spectrometry,and nuclear magnetic resonance were used to analyse the chemical structure of synthesized acrylates.In addition,various titration methods and rheology tests were applied to characterize acrylates.The chemical composition and thermal and mechanical properties of the developed polymers were studied by using FT-IR,solid-state nuclear magnetic resonance,thermal gravimetric analy-sis,differential scanning calorimetry,dynamic mechanical analysis,and universal strength testing apparatus.展开更多
A series of novel Michael addition products of fluorene to chalcone were obtained in the presence of sodium hydroxide under solvent-free condition. The advantages of this procedure were mild reaction conditions, simpl...A series of novel Michael addition products of fluorene to chalcone were obtained in the presence of sodium hydroxide under solvent-free condition. The advantages of this procedure were mild reaction conditions, simple protocol, and high yields. The structures of the products were characterized by IR, 1H NMR, MS and X-ray diffraction. The crystal of the new compound 3 h is Triclinic, space group P-1 with a = 0.97352（6） nm, b = 1.08918（7） nm, c = 2.58418（16） nm, α = 80.1400（10）°, β = 79.5490（10）°, γ = 64.2440（10）°, V = 2.4137（3） nm3, Z = 4, Dc=1.220 g/cm3,μ = 0.286 mm-1, F（000） = 920, R = 0.0656 and wR = 0.1554 for 5664 observed reflection with I 〉 2σ（I）.展开更多
In this paper, a novel solid state Michael-type addition reaction of N-heterocyclic compounds containing the active-CH group was investigated. 3-Methyl-1-phenyl-5-pyrazolone (MPP) and indole (In) reacted with 4-arylme...In this paper, a novel solid state Michael-type addition reaction of N-heterocyclic compounds containing the active-CH group was investigated. 3-Methyl-1-phenyl-5-pyrazolone (MPP) and indole (In) reacted with 4-arylmethylene-3-methyl-1-phenyl-5-pyrazolone (1) in the solid state at room temperature to give the corresponding adducts, aryl-4,4'-bis(5-hydroxy-3-methyl-1-phenyl-pyrazolyl) methane (2a-n) and 1-aryl-1-(5'-hydroxy-3'-methyl-1'-phenyl-4'-pyrazolyl)-1-(3 ''-indolyl) methane (3a-n), respectively. This is a feasible method for preparing the compound which contains two heterocyclic groups on the same carbon.展开更多
The iron containing ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate （[C4mim]C1/FeCl3; Z = 0.5） proved to be an efficient catalyst for the solvent-free metal catalyzed Michael addition of β-keto esters a...The iron containing ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate （[C4mim]C1/FeCl3; Z = 0.5） proved to be an efficient catalyst for the solvent-free metal catalyzed Michael addition of β-keto esters and enones. Due to the ionic structure of the catalyst, a significant acceleration of the reaction rate was observed under microwave conditions. Furthermore, recycling of the ionic liquid catalyst could be performed after simply distilling off the products.展开更多
A convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3-indanedione at room temperature in PEG-400 is described. The use of PEG-400 as the reaction...A convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3-indanedione at room temperature in PEG-400 is described. The use of PEG-400 as the reaction medium and avoiding the use of any catalyst makes the process environmentally benign. Seven new compounds are reported.展开更多
基金supported by the National Natural Science Foundation of China (21425627,21376279)~~
文摘Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition reactions in water at room temperature. The mechanism responsible for the moder‐ate activity and enantioselectivity of the β‐cyclodextrin derivatives was explored using nuclear magnetic resonance spectroscopy, namely 2D 1H rotating‐frame overhauser effect spectroscopy （ROESY）, ultraviolet absorption spectroscopy, and quantum chemical calculations, which provide a useful technique for investigating the formation of inclusion complexes. The effects of the pH of the reaction medium, theβ‐cyclodextrin derivative dosage, the structure of the modifying amino group, and various substrates on the yield and enantioselectivity were investigated. The results indicated that these factors had an important effect on the enantiomeric excess （ee） in the reaction system. Experiments using a competitor for inclusion complex formation showed that a hydrophobic cavity is necessary for enantioselective Michael addition. A comparison of the reactions using 4‐nitro‐β‐nitrostyrene and 2‐nitro‐β‐nitrostyrene showed that steric hindrance improved the enan‐tioselectivity. This was verified by the optimized geometries obtained from quantum chemical cal‐culations. An ee of 71%was obtained in the asymmetric Michael addition of cyclohexanone and 2‐nitro‐β‐nitrostyrene, using （S）‐2‐aminomethylpyrrolidine‐modified β‐CD as the catalyst, in an aqueous buffer solution, i.e., CH3COONa‐HCl （pH 7.5）.
文摘Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
基金This work was supported by the National Key Basic Research Special Foundation （No.2007CB815202 and No.2009CB220010） and the National Natural Science Foundation of China （No.20833008）.
文摘The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their distinct sensing mechanisms and experimental phenomena. The time-dependent density functional theory has been applied to investigate the ground states and the first singlet excited electronic states of the sensor as well as their possible Michael reaction products with cyanide, with a view to monitoring their geometries and photophysieal properties. The theoretical study indicates that the protic water solvent could lead to final Michael addition product of sensor a in the ground state, while the aprotic acetonitrile solvent could lead to carbanion as the final product of sensor b. Furthermore, the Michael reaction product of sensor a has been proved to have a torsion structure in its first singlet excited state. Correspondingly, sensor b also has a torsion structure around the nitrovinyl moiety in its first singlet excited state, while not in its carbanion structure. This could explain the observed strong fluorescence for sensor a and the quenching fluorescence for the sensor b upon the addition of the cyanide anions in the relevant sensing mechanisms.
基金Supported by the Jilin University Innovation Fund(No.419070200033).
文摘A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A range of chalcones and nitroalkenes together with active methylene compounds have been converted smoothly to the corresponding products in high yields.
基金Supported by the National Natural Science Foundation of China(Nos.20533010 and 20873041)Shanghai Leading Academic Discipline Project,China(No.B409)
文摘Michael addition of active methylene compounds to α,β-unsaturated carboxylic esters and nitriles was effectively catalyzed by a basic ionic liquid, 1-butyl-3-methylimidazolium acetate（[Bmim]OAc）. The his-addition products were selectively obtained in high yields under mild reaction conditions.
文摘Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
基金Project No. 20572040 was supported by National Natural Science Foundation of China.
文摘An efficient Michael addition of indoles to unsaturated enones, such as chalcones and β-nitrostyrenes, was achieved in the presence of a catalytic amount of nitrosonium tetrafluoroborate in ethyl ether. 2007 Long Min Wu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitromethane, and active methylene compounds were converted smoothly to the corresponding products in high yields. The simple procedure, very mild conditions, high yields, and reuse of the IL without any loss of catalytic activity make this protocol considerably attractive for academic researches and practical applications.
基金This work was partially supported by the National Natural Science Foundation of China.
文摘Michael addition of the chiral alpha,beta -unsaturated ester 2 with furyl lithium proceeded in syn manner with excellent diastereoselectivity. The diastereoselectivity was not affected by the configuration of the double bond in 2.
文摘C-H bond can undergo vicarious Michael addition reaction （VMA） with doubleactivated double bond in the absence of strong base and catalyst under mild conditions. Intramolecular H-bonding, electron-withdrawing inductive effect, and steric hindrance at aposition of nucleophile facilitates C-H addition over N-H addition. By using VMA, high branching multiplicity, novel branching pattern, controllable density and distribution of functional groups can be envisioned for novel dendrimer synthesis.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,China
文摘A Zn/NH4Cl system was exploited at room temperature to promote the Michael addition reaction of various primary and secondary amines with α,β-unsaturated esters,nitriles,amides,and ketones to give the corresponding saturated amines under the mild condition in high yield.
文摘Promoted by SmI3 β -diketones， β-ketoesters and α -cyano esters were added to α,β -unsaturated esters to form δ-carbonyl esters in mild conditions in moderate to good yields.
基金We appreciate the National Natural Science Foundation of China （No. 20962018, 20862015, 20762009 and 20562011） for supporting this research.
文摘An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temperature.
基金funded by the Latvian Council of Science,project“High bio-based content thermoset polymer foam development from plant origin oils (Bio-Mer)” (No.lzp-2020/1-0385)supported by ESF within Project"Strengthening of PhD students and academic personnel of Riga Technical University and BA School of Business and Finance in the strategic fields of specialization" (No 8.2.2.0/20/I/008)of the Specific Objective 8.2.2"To Strengthen Academic Staffof Higher Education Institutions in Strategic Specialization Areas"of the Operational Programme"Growth and Employment”supported by Riga Technical University’s Doctoral Grant programme.
文摘It is crucial to adapt the processing of forest bio-resources into biochemicals and bio-based ad-vanced materials in order to transform the current economic climate into a greener economy.Tall oil,as a by-product of the Kraft process of wood pulp manufacture,is a promising resource for the extraction of various value-added products.Tall oil fatty acids-based multifunctional Michael acceptor acrylates were developed.The suitability of developed acrylates for polymerization with tall oil fatty acids-based Michael donor acetoacetates to form a highly cross-linked polymer ma-terial via the Michael addition was investigated.With this novel strategy,valuable chemicals and innovative polymer materials can be produced from tall oil in an entirely new way,making a significant contribution to the development of a forest-based bioeconomy.Two different tall oil-based acrylates were successfully synthesized and characterized.Synthesized acrylates were successfully used in the synthesis of bio-based thermoset polymers.Obtained polymers had a wide variety of mechanical and thermal properties(glass transition temperature from-12.1 to 29.6°C by dynamic mechanical analysis,Young’s modulus from 15 to 1760 MPa,and stress at break from 0.9 to 16.1 MPa).Gel permeation chromatography,Fourier-transform infrared(FT-IR)spectroscopy,matrix-assisted laser desorption/ionization-time of flight mass spectrometry,and nuclear magnetic resonance were used to analyse the chemical structure of synthesized acrylates.In addition,various titration methods and rheology tests were applied to characterize acrylates.The chemical composition and thermal and mechanical properties of the developed polymers were studied by using FT-IR,solid-state nuclear magnetic resonance,thermal gravimetric analy-sis,differential scanning calorimetry,dynamic mechanical analysis,and universal strength testing apparatus.
文摘A series of novel Michael addition products of fluorene to chalcone were obtained in the presence of sodium hydroxide under solvent-free condition. The advantages of this procedure were mild reaction conditions, simple protocol, and high yields. The structures of the products were characterized by IR, 1H NMR, MS and X-ray diffraction. The crystal of the new compound 3 h is Triclinic, space group P-1 with a = 0.97352（6） nm, b = 1.08918（7） nm, c = 2.58418（16） nm, α = 80.1400（10）°, β = 79.5490（10）°, γ = 64.2440（10）°, V = 2.4137（3） nm3, Z = 4, Dc=1.220 g/cm3,μ = 0.286 mm-1, F（000） = 920, R = 0.0656 and wR = 0.1554 for 5664 observed reflection with I 〉 2σ（I）.
基金Project supported by the National Natural Science Foundation of China.
文摘In this paper, a novel solid state Michael-type addition reaction of N-heterocyclic compounds containing the active-CH group was investigated. 3-Methyl-1-phenyl-5-pyrazolone (MPP) and indole (In) reacted with 4-arylmethylene-3-methyl-1-phenyl-5-pyrazolone (1) in the solid state at room temperature to give the corresponding adducts, aryl-4,4'-bis(5-hydroxy-3-methyl-1-phenyl-pyrazolyl) methane (2a-n) and 1-aryl-1-(5'-hydroxy-3'-methyl-1'-phenyl-4'-pyrazolyl)-1-(3 ''-indolyl) methane (3a-n), respectively. This is a feasible method for preparing the compound which contains two heterocyclic groups on the same carbon.
基金financially supported by the Hochschuljubil umsstiftung der Stadt Wien
文摘The iron containing ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate （[C4mim]C1/FeCl3; Z = 0.5） proved to be an efficient catalyst for the solvent-free metal catalyzed Michael addition of β-keto esters and enones. Due to the ionic structure of the catalyst, a significant acceleration of the reaction rate was observed under microwave conditions. Furthermore, recycling of the ionic liquid catalyst could be performed after simply distilling off the products.
文摘A convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3-indanedione at room temperature in PEG-400 is described. The use of PEG-400 as the reaction medium and avoiding the use of any catalyst makes the process environmentally benign. Seven new compounds are reported.
