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
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
[Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly sus...[Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly susceptible to disease as experimental material, the changes of catalase(CAT), and superoxide dismutase(SOD) and MDA activities in rice treated by BABA were investigated. [Result] In rice plants treated by BABA, the activities of CAT and SOD increased, meanwhile the MDA content also rose to some extent, resulting in the disease resistance to rice blast. [Conclusion] By influencing reactive oxygen metabolism, BABA endows rice plants with resistance to rice blast. BABA is safe to environment and has highly resistance-inducing capacity, it could be generalized in production.展开更多
Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ket...Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.展开更多
The synthesis of two series of [3-amino ketones containing a p-aminobenzoic acid moiety （TM.1 and TM-2） using a modified protocol of the Mannich reaction is reported. The molecular structures of a total of tweenty t...The synthesis of two series of [3-amino ketones containing a p-aminobenzoic acid moiety （TM.1 and TM-2） using a modified protocol of the Mannich reaction is reported. The molecular structures of a total of tweenty three new target compounds were characterized by ~H NMR, 1~C NMR, ESI-MS and HR-MS. Subsequently, their antidiabetic activities were screened in vitro. The c^-glucodase inhibition （c^-GI） activity of compound le reached a remarkable level of 66.50%. The peroxisome proliferator- activated receptor （PPAR） relative activation activities of six compounds are above 80%, and in particular 2i displays an un- precedentedly high PPAR of 130.91%. The structure-activity relationships of the compounds were established. 2i is also sub- ject to further in-depth investigation.展开更多
A series of novel homochiral β-oligopeptides bearing aryl side chains was designed and synthesized from （S）-β-phenyl-β-amino acid derivatives by solution-phase methods. By means of circular dichroism（CD）, Fouri...A series of novel homochiral β-oligopeptides bearing aryl side chains was designed and synthesized from （S）-β-phenyl-β-amino acid derivatives by solution-phase methods. By means of circular dichroism（CD）, Fourier- transform infrared spectrometry（FTIR）, powder X-ray diffraction analysis（XRD） and density functional theory（DFT） calculations, we suggest that dipeptide P-2 and tripeptide P-3 adopt random coil-like conformations, pentapeptide P-5 and hexapeptide P-6 adopt stable 12-helix conformations in both solution and solid-state. Meanwhile, tetrapeptide P-4 adopt random coil-like conformation in solution and adopt 12-helix conformation in solid state.展开更多
A novel organophosphorus compound containing the structure of bothβ-amino acid andβ-aminophosphonate is designed and synthesized.Arbuzov reaction with P（OEt）_3,the N-Boc protected iodide 3 cannot provide the desir...A novel organophosphorus compound containing the structure of bothβ-amino acid andβ-aminophosphonate is designed and synthesized.Arbuzov reaction with P（OEt）_3,the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates,the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.展开更多
Saccharose was applied as an efficient and homogenous catalyst for a one-pot,three-component Mannich reaction for the formation ofβ-aminoketones from aromatic aldehydes,anilines,and acetophenone at ambient temperatur...Saccharose was applied as an efficient and homogenous catalyst for a one-pot,three-component Mannich reaction for the formation ofβ-aminoketones from aromatic aldehydes,anilines,and acetophenone at ambient temperature in excellent yields.This protocol has the following advantages： mild conditions,high yields,clean reaction profiles,operational simplicity,and environmentally benign and simple work-up procedures.展开更多
Four new chiral 1,2,3,4-tetrahydroisoquinoline-derived β-amino alcohols were synthesized from L-DOPA in good yields. The structures of the target compounds were confirmed by ^1H NMR, ^13C NMR and MS.
A new set of reaction conditions has been established and allowed for the first non-noble Cu（II）-catalyzed asymmetric 1,4-hydrosilylation ofN-aryl β-enamino esters under air to afford a selection ofN-aryl β-amino ...A new set of reaction conditions has been established and allowed for the first non-noble Cu（II）-catalyzed asymmetric 1,4-hydrosilylation ofN-aryl β-enamino esters under air to afford a selection ofN-aryl β-amino acid es- ters of moderate-to-good enantiopurities （ee up to 91%）.展开更多
Sitagliptin is the first new anti-diabetic drug in DPP-Ⅳ inhibitor class. The general synthesis of sitagliptin is by coupling of the β-amino acid fragment with the heterocycle fragment. Though the specific β-amino ...Sitagliptin is the first new anti-diabetic drug in DPP-Ⅳ inhibitor class. The general synthesis of sitagliptin is by coupling of the β-amino acid fragment with the heterocycle fragment. Though the specific β-amino acid can be easily made from the corresponding R-amino acid by Arndt-Eistert hornologation, the optically pure precursor R-amino acid is difficult to prepare. We herein reported a practical protocol to make the trifluorophenyl substituted R-amino acid 4 in 〉99.9% ee and 40.3% yield by the enzymatic resolution employing enantioselective hydrolysis and a general separation procedure. This protocol requires only cheap starting materials and friendly reaction condition. The procedure not only allows people to prepare the drug substance, but also provides an alternative method for prepareing the rare α-amino acid and the subsequent β-amino acid.展开更多
The nucleophilic ring opening of epoxides with amines is a well known route for the synthesis of β-amino alcohols. The use of carbonates offers significant advantages over epoxides as they are far less hazardous mate...The nucleophilic ring opening of epoxides with amines is a well known route for the synthesis of β-amino alcohols. The use of carbonates offers significant advantages over epoxides as they are far less hazardous materials, safe for handling, do not require high-pressure equipment and most notably the possibility of solvent less reactions. In this work, utilization of zeolite as host catalyst in the reaction media for synthesis of β-amino alcohols without using solvent is reported.展开更多
The conformations of four β-amino acids in a model peptide environment were investigated using Hartree-Fock (HF) and density functional theory (DFT) methods in gas phase and with solvation. Initial structures were ob...The conformations of four β-amino acids in a model peptide environment were investigated using Hartree-Fock (HF) and density functional theory (DFT) methods in gas phase and with solvation. Initial structures were obtained by varying dihedral angles in increments of 45° in the range 0° - 360°. Stable geometries were optimized at both levels of theory with the correlation consistent double-zeta basis set with polarization functions (cc-pVDZ). The results suggest that solvation generally stabilizes the conformations relative to the gas phase and that intramolecular hydrogen bonding may play an important role in the stability of the conformations. The β3 structures, in which the R-group of the amino acid is located on the carbon atom next to the N-terminus, are somewhat more stable relative to each other than the β2 structures which have the R-group on the carbon next to the carbonyl.展开更多
tert-Butyl （R）-3-amino-3-（3-fluorophenyl）propanoate（5） was prepared with conventional debenzylation method. However, the tert-butyl （R）-3-[（S）-1-phenylethyl-amino]-3-（3-fluorophenyl） propanoate（6） and te...tert-Butyl （R）-3-amino-3-（3-fluorophenyl）propanoate（5） was prepared with conventional debenzylation method. However, the tert-butyl （R）-3-[（S）-1-phenylethyl-amino]-3-（3-fluorophenyl） propanoate（6） and tert-butyl （R）-3-amino-3-phenylpropanoate（7） were generated as the byproducts under the general catalytic hydrogenation Pd（OH）2/C-H2 conditions. So a series of experiments was performed to optimize the reaction conditions so that product 5 could be obtained with high purity and yield. Finally an effective catalytic system, Pd/C-HCOOH-CH3OH, was discovered.展开更多
The regioselective ring-opening of epoxides with aniline and p-chlorop niline catalyzed by copper(Ⅱ) triflate provides the corresponding β-amino alcohols in excellent yields.
An efficient and practical method is described for the ring-opening reactions of N-tosylaziridines with various thiols in water under mild conditions. Various surfactants have been evaluated to optimize the reactions....An efficient and practical method is described for the ring-opening reactions of N-tosylaziridines with various thiols in water under mild conditions. Various surfactants have been evaluated to optimize the reactions. Under optimal conditions, these reactions gave rise to the corresponding β-amino sulfides in good to excellent yields.展开更多
Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enant...Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enantiose-lectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with het-erocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst.展开更多
Halogen substituted β-amino acids, D,L-3-amino-3-（4-fluoro）phenylpropionic acid（D,L-HL1, 1） and D,L-3-amino-3-（4-bromo）phenylpropionic acid（D,L-HL2, 2）, as well as their Cu（II） coordination complexes [Cu（L...Halogen substituted β-amino acids, D,L-3-amino-3-（4-fluoro）phenylpropionic acid（D,L-HL1, 1） and D,L-3-amino-3-（4-bromo）phenylpropionic acid（D,L-HL2, 2）, as well as their Cu（II） coordination complexes [Cu（L1）2（CH3OH）2].2CH3OH（3） and [Cu（L2）2（CH3OH）2]-2CHaOH（4） were investigated and their single crystal structures were discussed in details. Supramolecular helical chains were found in β-amino acids 1 and 2 while there was no helix in their coordination complexes 3 and 4. The formation of supramolecular helixes could be due to the hydrogen bonds between terminal -NH3＋ and adjacent -COO- in β-amino acids 1 and 2. While, this kind of hydrogen bonds could not be observed in their Cu（II） coordination complexes 3 and 4, in which central-symmetrical dimers could be formed via coplanar coordinated bonds（N-Cu-O） between -NH2 and -COO-.展开更多
Two new optically active trans-2-atrfinocyclopropanecarboxylic esters （β-ACCs） of optical purity 91%-96% were concisely synthesized via ozonization, oxidation, Curtius rearrangement from commercial available optica...Two new optically active trans-2-atrfinocyclopropanecarboxylic esters （β-ACCs） of optical purity 91%-96% were concisely synthesized via ozonization, oxidation, Curtius rearrangement from commercial available optically active trans-chrysanthemate in total yield 36%.展开更多
The easily prepared and recoverable chiral N-sulfonylated fl-amino alcohol 2 in combination with Ti（OPr-i）4 was found to be an effective chiral catalyst for the enantioselective addition of alkynylzinc to ketones, w...The easily prepared and recoverable chiral N-sulfonylated fl-amino alcohol 2 in combination with Ti（OPr-i）4 was found to be an effective chiral catalyst for the enantioselective addition of alkynylzinc to ketones, which gave the useful products, i.e. chiral tertiary propargyl alcohols, with the ee up to 92%.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 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.
基金Supported by National Key Technology R&D Program During the Eleventh Five Year Plan (2006BAD08A04)Innovation Project(20076020)~~
文摘[Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly susceptible to disease as experimental material, the changes of catalase(CAT), and superoxide dismutase(SOD) and MDA activities in rice treated by BABA were investigated. [Result] In rice plants treated by BABA, the activities of CAT and SOD increased, meanwhile the MDA content also rose to some extent, resulting in the disease resistance to rice blast. [Conclusion] By influencing reactive oxygen metabolism, BABA endows rice plants with resistance to rice blast. BABA is safe to environment and has highly resistance-inducing capacity, it could be generalized in production.
基金the financial support from the National Natural Science Foundation of China(Nos.20902073 and 21062017)the Natural Science Foundation of Gansu Province(No.096RJZA116)the Scientific and Technological Innovation Engineering program of Northwest Normal University(Nos.nwnu-kjcxgc-03-64,nwnulkqn -10-15)
文摘Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.
基金the Natural Science Foundation of Chongqing (2005BB5095)the Ph.D Research Foundation of Southwest University (SWNU, B2005010)the Scientific and Technological Project in Chongqing (CSTC, 2011AB5001) for financial support
文摘The synthesis of two series of [3-amino ketones containing a p-aminobenzoic acid moiety （TM.1 and TM-2） using a modified protocol of the Mannich reaction is reported. The molecular structures of a total of tweenty three new target compounds were characterized by ~H NMR, 1~C NMR, ESI-MS and HR-MS. Subsequently, their antidiabetic activities were screened in vitro. The c^-glucodase inhibition （c^-GI） activity of compound le reached a remarkable level of 66.50%. The peroxisome proliferator- activated receptor （PPAR） relative activation activities of six compounds are above 80%, and in particular 2i displays an un- precedentedly high PPAR of 130.91%. The structure-activity relationships of the compounds were established. 2i is also sub- ject to further in-depth investigation.
基金the National Natural Science Foundation of China（No.21172217）.
文摘A series of novel homochiral β-oligopeptides bearing aryl side chains was designed and synthesized from （S）-β-phenyl-β-amino acid derivatives by solution-phase methods. By means of circular dichroism（CD）, Fourier- transform infrared spectrometry（FTIR）, powder X-ray diffraction analysis（XRD） and density functional theory（DFT） calculations, we suggest that dipeptide P-2 and tripeptide P-3 adopt random coil-like conformations, pentapeptide P-5 and hexapeptide P-6 adopt stable 12-helix conformations in both solution and solid-state. Meanwhile, tetrapeptide P-4 adopt random coil-like conformation in solution and adopt 12-helix conformation in solid state.
文摘A novel organophosphorus compound containing the structure of bothβ-amino acid andβ-aminophosphonate is designed and synthesized.Arbuzov reaction with P（OEt）_3,the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates,the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.
基金financial support from the Research Council of University of Sistan and Baluchestan
文摘Saccharose was applied as an efficient and homogenous catalyst for a one-pot,three-component Mannich reaction for the formation ofβ-aminoketones from aromatic aldehydes,anilines,and acetophenone at ambient temperature in excellent yields.This protocol has the following advantages： mild conditions,high yields,clean reaction profiles,operational simplicity,and environmentally benign and simple work-up procedures.
文摘Four new chiral 1,2,3,4-tetrahydroisoquinoline-derived β-amino alcohols were synthesized from L-DOPA in good yields. The structures of the target compounds were confirmed by ^1H NMR, ^13C NMR and MS.
文摘A new set of reaction conditions has been established and allowed for the first non-noble Cu（II）-catalyzed asymmetric 1,4-hydrosilylation ofN-aryl β-enamino esters under air to afford a selection ofN-aryl β-amino acid es- ters of moderate-to-good enantiopurities （ee up to 91%）.
基金supported in part by grant from Science and Technology Program of Guangdong Province(No. 2007B031503005).
文摘Sitagliptin is the first new anti-diabetic drug in DPP-Ⅳ inhibitor class. The general synthesis of sitagliptin is by coupling of the β-amino acid fragment with the heterocycle fragment. Though the specific β-amino acid can be easily made from the corresponding R-amino acid by Arndt-Eistert hornologation, the optically pure precursor R-amino acid is difficult to prepare. We herein reported a practical protocol to make the trifluorophenyl substituted R-amino acid 4 in 〉99.9% ee and 40.3% yield by the enzymatic resolution employing enantioselective hydrolysis and a general separation procedure. This protocol requires only cheap starting materials and friendly reaction condition. The procedure not only allows people to prepare the drug substance, but also provides an alternative method for prepareing the rare α-amino acid and the subsequent β-amino acid.
文摘The nucleophilic ring opening of epoxides with amines is a well known route for the synthesis of β-amino alcohols. The use of carbonates offers significant advantages over epoxides as they are far less hazardous materials, safe for handling, do not require high-pressure equipment and most notably the possibility of solvent less reactions. In this work, utilization of zeolite as host catalyst in the reaction media for synthesis of β-amino alcohols without using solvent is reported.
文摘The conformations of four β-amino acids in a model peptide environment were investigated using Hartree-Fock (HF) and density functional theory (DFT) methods in gas phase and with solvation. Initial structures were obtained by varying dihedral angles in increments of 45° in the range 0° - 360°. Stable geometries were optimized at both levels of theory with the correlation consistent double-zeta basis set with polarization functions (cc-pVDZ). The results suggest that solvation generally stabilizes the conformations relative to the gas phase and that intramolecular hydrogen bonding may play an important role in the stability of the conformations. The β3 structures, in which the R-group of the amino acid is located on the carbon atom next to the N-terminus, are somewhat more stable relative to each other than the β2 structures which have the R-group on the carbon next to the carbonyl.
基金Supported by the National Key New Drug Creation Program of China(No.2009ZX09103-001)the Jiangsu Key Laboratory of Molecular Targeted Antitumor Drug Research Foundation China(No.BM2008201)
文摘tert-Butyl （R）-3-amino-3-（3-fluorophenyl）propanoate（5） was prepared with conventional debenzylation method. However, the tert-butyl （R）-3-[（S）-1-phenylethyl-amino]-3-（3-fluorophenyl） propanoate（6） and tert-butyl （R）-3-amino-3-phenylpropanoate（7） were generated as the byproducts under the general catalytic hydrogenation Pd（OH）2/C-H2 conditions. So a series of experiments was performed to optimize the reaction conditions so that product 5 could be obtained with high purity and yield. Finally an effective catalytic system, Pd/C-HCOOH-CH3OH, was discovered.
基金Project (No. 29790127) supported by the National Natural Science Foundation of China
文摘 The regioselective ring-opening of epoxides with aniline and p-chlorop niline catalyzed by copper(Ⅱ) triflate provides the corresponding β-amino alcohols in excellent yields.
基金Project supported by the National Natural Science Foundation of China （Nos. ＇20862009, 20962010）, Jiangxi Educational Committee （No. G J J10386） and the National Natural Science Foundation of Jiangxi Province （No. 2008GQH0026）.
文摘An efficient and practical method is described for the ring-opening reactions of N-tosylaziridines with various thiols in water under mild conditions. Various surfactants have been evaluated to optimize the reactions. Under optimal conditions, these reactions gave rise to the corresponding β-amino sulfides in good to excellent yields.
基金Project supported by the National Key Project for Basic Research （No. 2010CB126105）, Key Technologies R＆D Program （No. 2011BAE06B05）, the National Natural Science Foundation of China （No. 20872021） and Innovation Foundation for Graduate Students in Guizhou University （No. 2010023）.
文摘Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enantiose-lectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with het-erocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst.
基金Supported by the National Natural Science Foundation of China（Nos.21071018, 21271026）.
文摘Halogen substituted β-amino acids, D,L-3-amino-3-（4-fluoro）phenylpropionic acid（D,L-HL1, 1） and D,L-3-amino-3-（4-bromo）phenylpropionic acid（D,L-HL2, 2）, as well as their Cu（II） coordination complexes [Cu（L1）2（CH3OH）2].2CH3OH（3） and [Cu（L2）2（CH3OH）2]-2CHaOH（4） were investigated and their single crystal structures were discussed in details. Supramolecular helical chains were found in β-amino acids 1 and 2 while there was no helix in their coordination complexes 3 and 4. The formation of supramolecular helixes could be due to the hydrogen bonds between terminal -NH3＋ and adjacent -COO- in β-amino acids 1 and 2. While, this kind of hydrogen bonds could not be observed in their Cu（II） coordination complexes 3 and 4, in which central-symmetrical dimers could be formed via coplanar coordinated bonds（N-Cu-O） between -NH2 and -COO-.
基金Finacial support by the National Natural Science Foundation of China(No.2047211)is gratefully acknowledged.
文摘Two new optically active trans-2-atrfinocyclopropanecarboxylic esters （β-ACCs） of optical purity 91%-96% were concisely synthesized via ozonization, oxidation, Curtius rearrangement from commercial available optically active trans-chrysanthemate in total yield 36%.
基金Project supported by the National Natural Science Foundation of China （Nos. 29925205, 30271488, 20021001 and 203900501）.
文摘The easily prepared and recoverable chiral N-sulfonylated fl-amino alcohol 2 in combination with Ti（OPr-i）4 was found to be an effective chiral catalyst for the enantioselective addition of alkynylzinc to ketones, which gave the useful products, i.e. chiral tertiary propargyl alcohols, with the ee up to 92%.
