Cerium trichloride heptahydrate(CeCl_3·7H_2O) was found to be an efficient and recyclable catalyst for the three-component direct Mannich reaction of anilines and benzaldehydes with acetophenone.This protocol has...Cerium trichloride heptahydrate(CeCl_3·7H_2O) was found to be an efficient and recyclable catalyst for the three-component direct Mannich reaction of anilines and benzaldehydes with acetophenone.This protocol has advantages of high yield,no environmental pollution,mild condition,and simple work-up procedure.展开更多
Amide ionic liquids （MLs）/L-proline synergistic catalyzed Mannich reactions of isovaleraldehyde, methyl ketones, and aromatic amines were carried out in moderate to high yields （ up to 96% ） and high stereo select...Amide ionic liquids （MLs）/L-proline synergistic catalyzed Mannich reactions of isovaleraldehyde, methyl ketones, and aromatic amines were carried out in moderate to high yields （ up to 96% ） and high stereo selectivities （ 〉99% e. e. ）. The products were easily isolated by extraction; and the catalyst system was readily recycled at least thrice without significant loss of efficiency. The scope of the substrates was studied and the interpretation of the manifest improvement of the reaction rates and enantio-selectivity of the novel catalyst system was speculated.展开更多
During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of produc...During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of product IM is postulated and discussed on the basis of deuterium labelling.展开更多
This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calcula...This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 438 8 kJ/mol and 393 9 kJ/mol respectively. The activation energy of the rate controlling step of the Mannich reaction which contains the potential Mannich reagent is 274 7 kJ/mol. Therefore, it can be derived that the potential Mannich reagent can increase the rate of the reaction remarkably. The reasons for this have been discussed in terms of the orbital match and electrostatic interaction between the atoms of reactant complexes. In this paper another different conjectured mechanism of the potential Mannich reagent which can reduce the activation energy is considerably studied.展开更多
The regioselective Mannich-type aminomethylation of hydroquinone afforded a nitrogen-containing compound, 2,5-bis-(morpholinomethyl)hydroquinone A, and its crystal structure was determined by single-crystal X-ray di...The regioselective Mannich-type aminomethylation of hydroquinone afforded a nitrogen-containing compound, 2,5-bis-(morpholinomethyl)hydroquinone A, and its crystal structure was determined by single-crystal X-ray diffraction. Crystal data for A: C16H24N2O4, Mr = 308.37, orthorhombic, space group Pbca, a = 10.479(4), b = 10.298(4), c = 14.865(5) ?, V = 1604.3(11) ?3, Z = 4, Dc = 1.277 g/cm3, F(000) = 664, μ = 0.092 mm-1, GOF = 1.078, the final R = 0.0508 and wR = 0.1075 for 1416 observed reflections with I > 2σ(I). There exist two intramolecular O–H…N hy- drogen bonds between the phenolic O atoms and the morpholine N donors and the morpholino rings assume the preferred chair conformation.展开更多
β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid de...β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.展开更多
A new approach modification reactions Atherton-Todd, Betty, Mannich and Doebner reactions with of arsine, stibine and bismuthine have been proposed in organometallic chemistry of these elements. These new reactions ca...A new approach modification reactions Atherton-Todd, Betty, Mannich and Doebner reactions with of arsine, stibine and bismuthine have been proposed in organometallic chemistry of these elements. These new reactions can be used for the synthesis of drugs and biologically active organic compound of arsenic, antimony and bismuth. A possible new mechanism of the reaction is proposed.展开更多
In study on the growth reaction mechanism of Eu-doped ZnO nanowire（NW）, the intermedium of reaction is characterized by measures such as FTIR. Besides, the influences of polyethyleneimine（PEI） on morphology, struc...In study on the growth reaction mechanism of Eu-doped ZnO nanowire（NW）, the intermedium of reaction is characterized by measures such as FTIR. Besides, the influences of polyethyleneimine（PEI） on morphology, structure and photoelectric property of NW are observed by SEM, TEM, XRD, UV-vis and PL spectrum. According to the result, it manifests that Eu-doped ZnO NW array growth response experiences six mutually associated reaction processes in PEI-HMTA system：（a） chelation reaction of PEI and Zn^2＋ ＆ Eu^3＋;（b） protonation reaction of PEI and NH_3;（c） decomposition reaction of hexamethylenetetramine（HMTA）;（d） Mannich reaction of HCHO and PEI;（e） formation of precursor of Eu-doped ZnO;（f） dehydration condensation of Eu-doped ZnO precursors, further forming a doped ZnO NW array. Among them, PEI is the key factor of the whole doping growth reaction process. It both plays a role in modifying the growth of ZnO NW and makes it become longer and thinner. In the meantime, it also facilitates doping of Eu and enables ZnO NW to capture more photoelectrons and higher transmission rate, which is critical to improve photovoltaic performance of optoelectronic devices.展开更多
The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory....The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C ＂C bond-forming step with the addition of enamine intermediate to the imine for the L-proline（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-amino acid）-catalyzed processes were reported.B3LYP/6-31G calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts（syn-selectivity for the ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.展开更多
Three N,N-heterylmethyl derivates of diaza-18-crown-6(I) are readily prepared by the reaction of (I) with paraformaldehyde and heterocyclic compounds in dry benzene.
Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the cor...Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.展开更多
Reaction of imines with 2-silyloxydiene catalyzed by ammonium chloride has been perfectly proceeded under environmentally friendly conditions to give Mannich-type product selectively. The reaction would proceed via Ma...Reaction of imines with 2-silyloxydiene catalyzed by ammonium chloride has been perfectly proceeded under environmentally friendly conditions to give Mannich-type product selectively. The reaction would proceed via Mannich-type mechanism, not cyclization/ring-opening process. Cyclopropanation of the corresponding Mannich-type product gave the precursor of prasugrel skeleton in high yield.展开更多
基金the financial support from Nanjing University of Science and Technology.
文摘Cerium trichloride heptahydrate(CeCl_3·7H_2O) was found to be an efficient and recyclable catalyst for the three-component direct Mannich reaction of anilines and benzaldehydes with acetophenone.This protocol has advantages of high yield,no environmental pollution,mild condition,and simple work-up procedure.
基金the National Natural Science Foundation of China(No 20576026)State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology(No 200402)+2 种基金Science & Technology Office of Hebei Province(No 04213036)Foundation of HebeiUniversity of Science and Technology(No XL2006021)Environmental Engineering Key Subject of Hebei Province
文摘Amide ionic liquids （MLs）/L-proline synergistic catalyzed Mannich reactions of isovaleraldehyde, methyl ketones, and aromatic amines were carried out in moderate to high yields （ up to 96% ） and high stereo selectivities （ 〉99% e. e. ）. The products were easily isolated by extraction; and the catalyst system was readily recycled at least thrice without significant loss of efficiency. The scope of the substrates was studied and the interpretation of the manifest improvement of the reaction rates and enantio-selectivity of the novel catalyst system was speculated.
基金the National Natural Science Foundation of China.
文摘During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of product IM is postulated and discussed on the basis of deuterium labelling.
文摘This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 438 8 kJ/mol and 393 9 kJ/mol respectively. The activation energy of the rate controlling step of the Mannich reaction which contains the potential Mannich reagent is 274 7 kJ/mol. Therefore, it can be derived that the potential Mannich reagent can increase the rate of the reaction remarkably. The reasons for this have been discussed in terms of the orbital match and electrostatic interaction between the atoms of reactant complexes. In this paper another different conjectured mechanism of the potential Mannich reagent which can reduce the activation energy is considerably studied.
基金This work was financially supported by the Natural Science Foundation of Tianjin (No. 013606111)
文摘The regioselective Mannich-type aminomethylation of hydroquinone afforded a nitrogen-containing compound, 2,5-bis-(morpholinomethyl)hydroquinone A, and its crystal structure was determined by single-crystal X-ray diffraction. Crystal data for A: C16H24N2O4, Mr = 308.37, orthorhombic, space group Pbca, a = 10.479(4), b = 10.298(4), c = 14.865(5) ?, V = 1604.3(11) ?3, Z = 4, Dc = 1.277 g/cm3, F(000) = 664, μ = 0.092 mm-1, GOF = 1.078, the final R = 0.0508 and wR = 0.1075 for 1416 observed reflections with I > 2σ(I). There exist two intramolecular O–H…N hy- drogen bonds between the phenolic O atoms and the morpholine N donors and the morpholino rings assume the preferred chair conformation.
基金the financial support form National Natural Science Foundation of China(No.20472116).
文摘β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.
文摘A new approach modification reactions Atherton-Todd, Betty, Mannich and Doebner reactions with of arsine, stibine and bismuthine have been proposed in organometallic chemistry of these elements. These new reactions can be used for the synthesis of drugs and biologically active organic compound of arsenic, antimony and bismuth. A possible new mechanism of the reaction is proposed.
基金Financially supported by the National Natural Science Foundation of China(Nos:51463023 and 21461028)Guangxi Key Laboratory of Farm Products Processing(Cultivation Base)Guangxi Colleges and Universities Program of Innovative Research Team and Outstanding Talent
文摘In study on the growth reaction mechanism of Eu-doped ZnO nanowire（NW）, the intermedium of reaction is characterized by measures such as FTIR. Besides, the influences of polyethyleneimine（PEI） on morphology, structure and photoelectric property of NW are observed by SEM, TEM, XRD, UV-vis and PL spectrum. According to the result, it manifests that Eu-doped ZnO NW array growth response experiences six mutually associated reaction processes in PEI-HMTA system：（a） chelation reaction of PEI and Zn^2＋ ＆ Eu^3＋;（b） protonation reaction of PEI and NH_3;（c） decomposition reaction of hexamethylenetetramine（HMTA）;（d） Mannich reaction of HCHO and PEI;（e） formation of precursor of Eu-doped ZnO;（f） dehydration condensation of Eu-doped ZnO precursors, further forming a doped ZnO NW array. Among them, PEI is the key factor of the whole doping growth reaction process. It both plays a role in modifying the growth of ZnO NW and makes it become longer and thinner. In the meantime, it also facilitates doping of Eu and enables ZnO NW to capture more photoelectrons and higher transmission rate, which is critical to improve photovoltaic performance of optoelectronic devices.
基金Supported by the National Natural Science Foundation of China(Nos.20773071,20901043)the Natural Science Foundation of Shandong Province,China(No.ZR2010BM024)the Project of Shandong Province Higher Educational Science and Technology Program,China(No.J10LB06)
文摘The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C ＂C bond-forming step with the addition of enamine intermediate to the imine for the L-proline（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-amino acid）-catalyzed processes were reported.B3LYP/6-31G calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts（syn-selectivity for the ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.
文摘Three N,N-heterylmethyl derivates of diaza-18-crown-6(I) are readily prepared by the reaction of (I) with paraformaldehyde and heterocyclic compounds in dry benzene.
文摘Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.
文摘Reaction of imines with 2-silyloxydiene catalyzed by ammonium chloride has been perfectly proceeded under environmentally friendly conditions to give Mannich-type product selectively. The reaction would proceed via Mannich-type mechanism, not cyclization/ring-opening process. Cyclopropanation of the corresponding Mannich-type product gave the precursor of prasugrel skeleton in high yield.
