Enamines, promoted by the samarium/samarium diiodide mixed reagent, were synthesized via the cross-coupling of thioamides and diarylketones in good yields.
<span style='font-family:Verdana;font-size:12px;'>The medicinal uses and applications of metal complexes are of increasing clinical and commercial importance;this is as a result of some level of success ...<span style='font-family:Verdana;font-size:12px;'>The medicinal uses and applications of metal complexes are of increasing clinical and commercial importance;this is as a result of some level of success </span><span style='font-family:Verdana;font-size:12px;'>achieved so far. In this regard, novel enamine free-base ligands were synthesized</span><span style='font-family:Verdana;font-size:12px;'> by the condensation of terephthalaldehyde and 2-(methylamino)ethanol. This afforded a dinegative </span><i><span style='font-family:Verdana;font-size:12px;'>ONNO</span></i><span style='font-family:Verdana;font-size:12px;'> donor enamine, free base, characterized using </span><sup><span style='font-family:Verdana;font-size:12px;'>1</span></sup><span style='font-family:Verdana;font-size:12px;'>H and </span><sup><span style='font-family:Verdana;font-size:12px;'>13</span></sup><span style='font-family:Verdana;font-size:12px;'>C NMR, Fourier-transformed infrared and UV-vis spectroscopy. Coordination compounds of the enamine were also synthesized using Cu(II), Ni(II), Co(II) and VO(IV) ions. These complexes were characterized by electronic, IR spectrophotometry, mass spectrometry, magnetic susceptibility and </span><span style='font-family:Verdana;font-size:12px;'>E</span><span style='font-family:Verdana;font-size:12px;'>DX. The compounds were thereafter evaluated for their antimicrobial and cytotoxic activities. The data obtained w</span><span style='font-size:12px;font-family:Verdana;'>ere</span><span style='font-size:12px;font-family:Verdana;'> supportive of a</span><span style='font-size:12px;font-family:Verdana;'>n</span><span style='font-size:10.0pt;font-family:''><span style='font-family:Verdana;font-size:12px;'> octahedral geometry</span><span style='font-family:Verdana;font-size:12px;'> for the Cu(II) complex, a square-pyramidal geometry for the vanadium complex and a 4-coordinate square-planar geometry for both the cobalt and nickel complexes. The magnetic susceptibility data revealed that the complexes are magnetically dilute and mononuclear with exception of the cobalt complex. The ligands and the complexes did not exhibit significant antimicrobial and cytotoxic assays, indicative of the nontoxicity of the ligand and complexe</span><span style='font-family:Verdana;font-size:12px;'>s.</span></span>展开更多
Many proline-catalyzed asymmetric addition reactions with ketones as substrates were assumed to involve a key intermediate, an enamine, produced by the condensation of proline and ketone. In this paper, the key interm...Many proline-catalyzed asymmetric addition reactions with ketones as substrates were assumed to involve a key intermediate, an enamine, produced by the condensation of proline and ketone. In this paper, the key intermediate enamines derived from L-proline and cyclohexanone （or acetone） as well as the corresponding oxazolidinone and imine tautomers have been investigated by means of density functional calculations at the B3LYP/6-311＋G^＊＊ level. The predicted order of stability for these tautomers is oxazolidinones 〉 enamines 〉 imines in gas phase and oxazolidinones 〉 imines 〉 enamines in aprotic THF solvent. This prediction explains why enamine intermediate can not be observed experimentally. The predicted energy/enthalpy difference between the formal oxazolidinone structure and the zwitterionic imine structures is very small in THF solvent, suggesting the oxazolidinone-to-imine tautomerization can be readily induced in solvent. ^13C NMR chemical shifts of the oxazolidinone and imine structures have been computed and used to explain the experimental NMR spectra observed in oxazolidinone-to-imine tautomerization induced by protic solvent.展开更多
Compound 5-methyl-2-phenyl-4-[（Z）-3-tolylamino-phenylmethylene]pyrazol-3（2H）-one （C24H21N3O） crystallizes in the triclinic system, space group P1, with a = 9.267（3）, b = 9.904（4）,c = 12.035（4） A°, α ...Compound 5-methyl-2-phenyl-4-[（Z）-3-tolylamino-phenylmethylene]pyrazol-3（2H）-one （C24H21N3O） crystallizes in the triclinic system, space group P1, with a = 9.267（3）, b = 9.904（4）,c = 12.035（4） A°, α = 97.896（6）, β = 103.865（6）, γ = 107.950（6）°, Mr= 367.44, Z = 2, V = 993.2（6）A°^3,Dc = 1.229 g/cm^3,μ（MoKa） = 0.077 mm^-1 and F（000） = 388. The structure was refined to R =0.0444 and wR = 0.1199 for 2903 observed reflections （I 〉 2σ（I））. The results of ^1H NMR and single-crystal X-ray diffraction studies showed the enamine character of the compound. The strong intramolecular hydrogen bonds in the large conjugate system, together with weak intermolecular C-H……π hydrogen bonding and π……π stacking, lead to the formation of a multi-dimensional supramolecular network.展开更多
Brønsted acid-promoted;metal-free cascade reaction of easily available enamines/imines with diazopyruvates has been demonstrated.With triflic acid as the promoter;the reaction proceeds smoothly at room temperatur...Brønsted acid-promoted;metal-free cascade reaction of easily available enamines/imines with diazopyruvates has been demonstrated.With triflic acid as the promoter;the reaction proceeds smoothly at room temperature through sequential diazo protonation;nucleophilic enamine N-addition/C-addition and dehydrative aromatisa-tion in a highly regioselective manner.Interestingly;the regioselectivity of the reaction is governed by the un-usual enamine N-nucleophilic addition.The method provides an operationally trivial approach to the synthesis of multisubstituted pyrroles including tri-;tetra-;and penta-substituted derivatives as well as N-H free pyrroles with diverse functionalities in good yields under extraordinarily simple and mild conditions.The utility of the method is illustrated by the rapid assembly of polysubstituted bispyrroles and an array of diversely structured pyrrole derivatives.展开更多
C(sp^(2))-H amination represents an attractive approach for the synthesis of enamines,which is intrinsically associated with the challenge of controlling of stereochemistry and primarily relying on transition-metal ca...C(sp^(2))-H amination represents an attractive approach for the synthesis of enamines,which is intrinsically associated with the challenge of controlling of stereochemistry and primarily relying on transition-metal catalysis.Herein,a metal-free C(sp^(2))-H amination ofα-substituted styrenes has been achieved,leading to stereodivergent formation of both E-and Z-enamines in 50%–97%yield under mild conditions by using PhI(OAc)_(2) as a green oxidant and ortho-phenylenediamines as nitrogen source.Interestingly,the Z/E selectivity can be controlled readily by switching the reaction medium.E-isomers were formed preferentially in THF,whereas n-hexane favored the formation of Z-isomers.Preliminary mechanistic studies suggested that in situ formed ortho-benzoquinone diimides are the key intermediates,and there is a correlation between solvent polarity and stereoselectivity.This study enriches the chemical repertoire of ortho-benzoquinone diimides particularly with respect to sustainable amination.展开更多
A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to imin...A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.展开更多
The reaction of methyl α-diazoacetoacetate with enamines catalyzed by dirhodium and copper complexes un-derwent formal 1,3-dipolar addition to give 5-amino-4,5-dihydrofurans in moderate yields. The reaction was sug-g...The reaction of methyl α-diazoacetoacetate with enamines catalyzed by dirhodium and copper complexes un-derwent formal 1,3-dipolar addition to give 5-amino-4,5-dihydrofurans in moderate yields. The reaction was sug-gested to proceed via a nucleophilic addition of enamines to metal-carbenes and a subsequent intramolecular cycli-zation of the resulting zwitterionic intermediates.展开更多
Asymmetric catalytic hydrogenations of imines and enamines with chiral transition-metal complexes bearing chiral ligands are among the most green and powerful approaches for the elaboration of chiral amine structures ...Asymmetric catalytic hydrogenations of imines and enamines with chiral transition-metal complexes bearing chiral ligands are among the most green and powerful approaches for the elaboration of chiral amine structures in organic synthesis.This review focuses on recent applications of asymmetric hydrogenations of imine and enamine substrates in the total syntheses of natural products.These applications include diverse processes involving asymmetric transfer hydrogenation(ATH)and asymmetric hydrogenation(AH)to form key chiral amine motifs in natural products with good efficiency and high-level enantiocontrol.展开更多
The reactions of enamines (1a–b, 4, 6) with fluorinated acyl chlorides (2a–d ) produced fluorinated 1,3-diketones (3a–f) and 1,3-keto-aldehydes (7a–c) in good yields as well as byproducts fluorinated acylamides (5...The reactions of enamines (1a–b, 4, 6) with fluorinated acyl chlorides (2a–d ) produced fluorinated 1,3-diketones (3a–f) and 1,3-keto-aldehydes (7a–c) in good yields as well as byproducts fluorinated acylamides (5a–c). It is proposed that the reactions involve nucleophilic attack by the C-atom and/or N-atom of the enamines on acyl carbon of the fluorinated acyl chlorides.展开更多
Herein,organophotoredox-catalyzed annulation of enamines with sulfoxonium ylides to construct pyrrole derivatives is developed under transition-metal-free and mild condition.A broad range of readily accessible substra...Herein,organophotoredox-catalyzed annulation of enamines with sulfoxonium ylides to construct pyrrole derivatives is developed under transition-metal-free and mild condition.A broad range of readily accessible substrates are suitable for this protocol,providing a convenient and efficient approach to preparing pyrrole derivatives with satisfying yields.Mechanistically,a photoredox-mediated radical chain mechanistic pathway is proposed for this reaction by a synergistic experimental and computational study.Two key radicals,α-imino andα-carbonyl C-radicals derived from enamines and sulfoxonium ylides,respectively,could be generated via two steps of single-electron transfer in a photoredox catalytic loop.Subsequently,the formedα-carbonyl C-radical may attack the alkenyl moiety of enamines.Next,the formed radical adduct could undergo H-atom transfer with sulfoxonium ylides to regenerate the keyα-carbonyl C-radical and thus fulfill the chain propagation process.The afforded adduct intermediate could undergo an intramolecular cyclization followed by dehydration to furnish the desired pyrrole derivatives.展开更多
The cyclizations of alkyl 2-dimethoxyacetyl and 2-ethoxalyl-4-oxopentanoates were only effected by means of pyrrolidine with the formation of appropriately substituted 1-pyrrolidin-1-ylcyclopentadienes.
Synthesis of 4'-methoxyflavone, first by the reaction of 4 - methoxy acetophenone enamine with heptanedioyl chloride, then by dehydrogenation, is described.
1-Phenyl-1,3-butandione benzidine diketoimine 2a （C32H28N2O2, Mr = 472.56） was synthesized in high yield by the reaction of 1-phenyl-1,3-butandione with benzidine in absolute ethanol, and determined by X-ray structu...1-Phenyl-1,3-butandione benzidine diketoimine 2a （C32H28N2O2, Mr = 472.56） was synthesized in high yield by the reaction of 1-phenyl-1,3-butandione with benzidine in absolute ethanol, and determined by X-ray structure analysis. It crystallizes in the orthorhombic system, space group P21/c with a = 7.9839（16）, b = 12.910（3）, c = 12.358（3）A, α = 90.00, β= 93.71（3）,γ = 90.00°, V = 1271.1（4） A3, Z = 2, Dc = 1.235 g/cm^3,/1 = 0.077 mm^-1, F（000） = 500, the final R = 0.0717 and wR = 0.1187. It presents a linear centrosymmetric framework constituted by a linkage of benzidine as a bridge and two terminal 1-phenyl-1,3-butanedione moieties.展开更多
To investigate the structural form of gossypol and gossypolone Schiff＇s bases, seven relevant Schiff＇s bases were synthesized and the electrospray ionization-tandem mass spectrometry （ESI-MS/MS） with low-energy co...To investigate the structural form of gossypol and gossypolone Schiff＇s bases, seven relevant Schiff＇s bases were synthesized and the electrospray ionization-tandem mass spectrometry （ESI-MS/MS） with low-energy collision-induced dissociation was used to analyze their fragmentations. A common fragmentation pathway with the loss of RNH2 from those schiff＇s bases quasi-molecular ions was observed and proposed on the basis of their MS/MS spectra data. This common pathway indicated that those Schiff＇s bases existed mainly as the enamine form not the imine form previously showed in most reports.展开更多
The selective transalkylation of N-methyl tertiary amines with 3,4-dibromobutenolides is described. The N-methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of bu...The selective transalkylation of N-methyl tertiary amines with 3,4-dibromobutenolides is described. The N-methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of butenolide-containing tertiary enamines were obtained in moderate to good yields. Interestingly, the product 2b has shown a promising anticancer activity against HeLa cell lines （IC50 = 0.19μmol/L）.展开更多
We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts.A simple chiral primary-tertiary diamine catalyst derived from lphenylala...We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts.A simple chiral primary-tertiary diamine catalyst derived from lphenylalanine was found to readily promote this aza-Michael addition reaction with enamine protonation as the key stereogenic step,thus enabling the effective synthesis of α-chiral β-azido ketones with good yields and moderate enantioselectivities.展开更多
A 5πe carbonyl activation mode is reported on the basis of photo-induced single-electron-transfer （SET） oxidation of a secondary enamine. The resultant β-enaminyl radical intermediate was trapped by a wide range o...A 5πe carbonyl activation mode is reported on the basis of photo-induced single-electron-transfer （SET） oxidation of a secondary enamine. The resultant β-enaminyl radical intermediate was trapped by a wide range of Michael acceptors, producing β-alkylation products of β-ketocarbonyls in a highly efficient manner,展开更多
基金the National Natural Science Foundation of China(Project No.20072033)Specialized Research Fund for the Doctoral Program of Higher Education of China.
文摘Enamines, promoted by the samarium/samarium diiodide mixed reagent, were synthesized via the cross-coupling of thioamides and diarylketones in good yields.
文摘<span style='font-family:Verdana;font-size:12px;'>The medicinal uses and applications of metal complexes are of increasing clinical and commercial importance;this is as a result of some level of success </span><span style='font-family:Verdana;font-size:12px;'>achieved so far. In this regard, novel enamine free-base ligands were synthesized</span><span style='font-family:Verdana;font-size:12px;'> by the condensation of terephthalaldehyde and 2-(methylamino)ethanol. This afforded a dinegative </span><i><span style='font-family:Verdana;font-size:12px;'>ONNO</span></i><span style='font-family:Verdana;font-size:12px;'> donor enamine, free base, characterized using </span><sup><span style='font-family:Verdana;font-size:12px;'>1</span></sup><span style='font-family:Verdana;font-size:12px;'>H and </span><sup><span style='font-family:Verdana;font-size:12px;'>13</span></sup><span style='font-family:Verdana;font-size:12px;'>C NMR, Fourier-transformed infrared and UV-vis spectroscopy. Coordination compounds of the enamine were also synthesized using Cu(II), Ni(II), Co(II) and VO(IV) ions. These complexes were characterized by electronic, IR spectrophotometry, mass spectrometry, magnetic susceptibility and </span><span style='font-family:Verdana;font-size:12px;'>E</span><span style='font-family:Verdana;font-size:12px;'>DX. The compounds were thereafter evaluated for their antimicrobial and cytotoxic activities. The data obtained w</span><span style='font-size:12px;font-family:Verdana;'>ere</span><span style='font-size:12px;font-family:Verdana;'> supportive of a</span><span style='font-size:12px;font-family:Verdana;'>n</span><span style='font-size:10.0pt;font-family:''><span style='font-family:Verdana;font-size:12px;'> octahedral geometry</span><span style='font-family:Verdana;font-size:12px;'> for the Cu(II) complex, a square-pyramidal geometry for the vanadium complex and a 4-coordinate square-planar geometry for both the cobalt and nickel complexes. The magnetic susceptibility data revealed that the complexes are magnetically dilute and mononuclear with exception of the cobalt complex. The ligands and the complexes did not exhibit significant antimicrobial and cytotoxic assays, indicative of the nontoxicity of the ligand and complexe</span><span style='font-family:Verdana;font-size:12px;'>s.</span></span>
基金This work was supported by the National Natural Science Foundation of China (No. 20425312)
文摘Many proline-catalyzed asymmetric addition reactions with ketones as substrates were assumed to involve a key intermediate, an enamine, produced by the condensation of proline and ketone. In this paper, the key intermediate enamines derived from L-proline and cyclohexanone （or acetone） as well as the corresponding oxazolidinone and imine tautomers have been investigated by means of density functional calculations at the B3LYP/6-311＋G^＊＊ level. The predicted order of stability for these tautomers is oxazolidinones 〉 enamines 〉 imines in gas phase and oxazolidinones 〉 imines 〉 enamines in aprotic THF solvent. This prediction explains why enamine intermediate can not be observed experimentally. The predicted energy/enthalpy difference between the formal oxazolidinone structure and the zwitterionic imine structures is very small in THF solvent, suggesting the oxazolidinone-to-imine tautomerization can be readily induced in solvent. ^13C NMR chemical shifts of the oxazolidinone and imine structures have been computed and used to explain the experimental NMR spectra observed in oxazolidinone-to-imine tautomerization induced by protic solvent.
文摘Compound 5-methyl-2-phenyl-4-[（Z）-3-tolylamino-phenylmethylene]pyrazol-3（2H）-one （C24H21N3O） crystallizes in the triclinic system, space group P1, with a = 9.267（3）, b = 9.904（4）,c = 12.035（4） A°, α = 97.896（6）, β = 103.865（6）, γ = 107.950（6）°, Mr= 367.44, Z = 2, V = 993.2（6）A°^3,Dc = 1.229 g/cm^3,μ（MoKa） = 0.077 mm^-1 and F（000） = 388. The structure was refined to R =0.0444 and wR = 0.1199 for 2903 observed reflections （I 〉 2σ（I））. The results of ^1H NMR and single-crystal X-ray diffraction studies showed the enamine character of the compound. The strong intramolecular hydrogen bonds in the large conjugate system, together with weak intermolecular C-H……π hydrogen bonding and π……π stacking, lead to the formation of a multi-dimensional supramolecular network.
基金support from the National Natural Science Foundation of China(No.21971103)the Shenzhen Science and Technology Innovation Commission(No.JCYJ20200109141408054)the Guangdong Provincial Key Laboratory Of Catalysis(No.2020B121201002).
文摘Brønsted acid-promoted;metal-free cascade reaction of easily available enamines/imines with diazopyruvates has been demonstrated.With triflic acid as the promoter;the reaction proceeds smoothly at room temperature through sequential diazo protonation;nucleophilic enamine N-addition/C-addition and dehydrative aromatisa-tion in a highly regioselective manner.Interestingly;the regioselectivity of the reaction is governed by the un-usual enamine N-nucleophilic addition.The method provides an operationally trivial approach to the synthesis of multisubstituted pyrroles including tri-;tetra-;and penta-substituted derivatives as well as N-H free pyrroles with diverse functionalities in good yields under extraordinarily simple and mild conditions.The utility of the method is illustrated by the rapid assembly of polysubstituted bispyrroles and an array of diversely structured pyrrole derivatives.
基金supported by the National Natural Science Foundation of China(No.22001085)Shandong Provincial Natural Science Foundation(No.ZR2021QB148)+1 种基金Fundamental Research Funds for the Central Universities(No.HUST:2023JCYJ001)Research Institute of Zhejiang Sci-Tech University in Longgang(No.LGYJY2021013)for financial support。
文摘C(sp^(2))-H amination represents an attractive approach for the synthesis of enamines,which is intrinsically associated with the challenge of controlling of stereochemistry and primarily relying on transition-metal catalysis.Herein,a metal-free C(sp^(2))-H amination ofα-substituted styrenes has been achieved,leading to stereodivergent formation of both E-and Z-enamines in 50%–97%yield under mild conditions by using PhI(OAc)_(2) as a green oxidant and ortho-phenylenediamines as nitrogen source.Interestingly,the Z/E selectivity can be controlled readily by switching the reaction medium.E-isomers were formed preferentially in THF,whereas n-hexane favored the formation of Z-isomers.Preliminary mechanistic studies suggested that in situ formed ortho-benzoquinone diimides are the key intermediates,and there is a correlation between solvent polarity and stereoselectivity.This study enriches the chemical repertoire of ortho-benzoquinone diimides particularly with respect to sustainable amination.
基金the financial support from the National Science Foun-dation (CHE-1057569,W. W.)the China 111 Project (B07023,J. L. and W. W.)+1 种基金the National Natural Science Foundation of China (20972051,X. Y.-H.)the Science and Technology Commission of Shanghai Mu-nicipality (08430703900 & 08431901800,X. Y.-H.)
文摘A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to （E） selective a, β-unsamrated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.
基金Project supported by the National Natural Science Foundation of China (No. 20472061) Suzhou University (No. Q4109308) and the Key Laboratory of Organic Synthesis of Jiangsu Province (No. JSK004).
文摘The reaction of methyl α-diazoacetoacetate with enamines catalyzed by dirhodium and copper complexes un-derwent formal 1,3-dipolar addition to give 5-amino-4,5-dihydrofurans in moderate yields. The reaction was sug-gested to proceed via a nucleophilic addition of enamines to metal-carbenes and a subsequent intramolecular cycli-zation of the resulting zwitterionic intermediates.
基金This work was supported by the Fundamental Research Funds for the Central Universities(YJ201805,YJ201864).
文摘Asymmetric catalytic hydrogenations of imines and enamines with chiral transition-metal complexes bearing chiral ligands are among the most green and powerful approaches for the elaboration of chiral amine structures in organic synthesis.This review focuses on recent applications of asymmetric hydrogenations of imine and enamine substrates in the total syntheses of natural products.These applications include diverse processes involving asymmetric transfer hydrogenation(ATH)and asymmetric hydrogenation(AH)to form key chiral amine motifs in natural products with good efficiency and high-level enantiocontrol.
基金Project (No. 29272043) supported by the National Natural Science Foundation of China
文摘The reactions of enamines (1a–b, 4, 6) with fluorinated acyl chlorides (2a–d ) produced fluorinated 1,3-diketones (3a–f) and 1,3-keto-aldehydes (7a–c) in good yields as well as byproducts fluorinated acylamides (5a–c). It is proposed that the reactions involve nucleophilic attack by the C-atom and/or N-atom of the enamines on acyl carbon of the fluorinated acyl chlorides.
基金the National Natural Science Foundation of China(22373073)the project of scientific and technologic infrastructure of Suzhou(SZS201708)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)for financial support.
文摘Herein,organophotoredox-catalyzed annulation of enamines with sulfoxonium ylides to construct pyrrole derivatives is developed under transition-metal-free and mild condition.A broad range of readily accessible substrates are suitable for this protocol,providing a convenient and efficient approach to preparing pyrrole derivatives with satisfying yields.Mechanistically,a photoredox-mediated radical chain mechanistic pathway is proposed for this reaction by a synergistic experimental and computational study.Two key radicals,α-imino andα-carbonyl C-radicals derived from enamines and sulfoxonium ylides,respectively,could be generated via two steps of single-electron transfer in a photoredox catalytic loop.Subsequently,the formedα-carbonyl C-radical may attack the alkenyl moiety of enamines.Next,the formed radical adduct could undergo H-atom transfer with sulfoxonium ylides to regenerate the keyα-carbonyl C-radical and thus fulfill the chain propagation process.The afforded adduct intermediate could undergo an intramolecular cyclization followed by dehydration to furnish the desired pyrrole derivatives.
文摘The cyclizations of alkyl 2-dimethoxyacetyl and 2-ethoxalyl-4-oxopentanoates were only effected by means of pyrrolidine with the formation of appropriately substituted 1-pyrrolidin-1-ylcyclopentadienes.
文摘Synthesis of 4'-methoxyflavone, first by the reaction of 4 - methoxy acetophenone enamine with heptanedioyl chloride, then by dehydrogenation, is described.
文摘1-Phenyl-1,3-butandione benzidine diketoimine 2a （C32H28N2O2, Mr = 472.56） was synthesized in high yield by the reaction of 1-phenyl-1,3-butandione with benzidine in absolute ethanol, and determined by X-ray structure analysis. It crystallizes in the orthorhombic system, space group P21/c with a = 7.9839（16）, b = 12.910（3）, c = 12.358（3）A, α = 90.00, β= 93.71（3）,γ = 90.00°, V = 1271.1（4） A3, Z = 2, Dc = 1.235 g/cm^3,/1 = 0.077 mm^-1, F（000） = 500, the final R = 0.0717 and wR = 0.1187. It presents a linear centrosymmetric framework constituted by a linkage of benzidine as a bridge and two terminal 1-phenyl-1,3-butanedione moieties.
文摘To investigate the structural form of gossypol and gossypolone Schiff＇s bases, seven relevant Schiff＇s bases were synthesized and the electrospray ionization-tandem mass spectrometry （ESI-MS/MS） with low-energy collision-induced dissociation was used to analyze their fragmentations. A common fragmentation pathway with the loss of RNH2 from those schiff＇s bases quasi-molecular ions was observed and proposed on the basis of their MS/MS spectra data. This common pathway indicated that those Schiff＇s bases existed mainly as the enamine form not the imine form previously showed in most reports.
基金NSFC(No.21062014)the‘‘211’’Project in Ningxia University for financial support
文摘The selective transalkylation of N-methyl tertiary amines with 3,4-dibromobutenolides is described. The N-methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of butenolide-containing tertiary enamines were obtained in moderate to good yields. Interestingly, the product 2b has shown a promising anticancer activity against HeLa cell lines （IC50 = 0.19μmol/L）.
基金National Natural Science Foundation of China(NSFC Nos.21390400,21521002 and 21502198)the Ministry of Science and Technology,Chinese Academy of Sciences(No.QYZDJSSW-SLH023)for generous financial supportsupported by National Program for Support of Top-notch Young Professionals,CAS Youth Innovation Promotion Association and CAS onehundred talented program(D)
文摘We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts.A simple chiral primary-tertiary diamine catalyst derived from lphenylalanine was found to readily promote this aza-Michael addition reaction with enamine protonation as the key stereogenic step,thus enabling the effective synthesis of α-chiral β-azido ketones with good yields and moderate enantioselectivities.
基金We thank the National Natural Science Foundation of China （21390400, 21521002, 21572232 and 21672217） and the Chinese Academy of Sciences （QYZDJ-SSW-SLH023） for financial support. S. L. is supported by National Program of Top-notch Young Profes- sionals.
文摘A 5πe carbonyl activation mode is reported on the basis of photo-induced single-electron-transfer （SET） oxidation of a secondary enamine. The resultant β-enaminyl radical intermediate was trapped by a wide range of Michael acceptors, producing β-alkylation products of β-ketocarbonyls in a highly efficient manner,
