The oxidation on 1,4-substituted Hantzsch 1,4-dihydropyridines with nitrosonium tetrafluoroborate (NO+BF4-) in acetonitrile gave Hantzsch pyridines in good yields. In some cases the dealkylation occurred. The evidence...The oxidation on 1,4-substituted Hantzsch 1,4-dihydropyridines with nitrosonium tetrafluoroborate (NO+BF4-) in acetonitrile gave Hantzsch pyridines in good yields. In some cases the dealkylation occurred. The evidences to draw the mechanism were presented.展开更多
4-oxo-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy radical (TEMPO), a nitroxide, oxidized 4-substituted Hantzsch 1,4-dihydropyridines (DHP) under UV irradiation in CH3CN to give aromatic products in good yields. A possible...4-oxo-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy radical (TEMPO), a nitroxide, oxidized 4-substituted Hantzsch 1,4-dihydropyridines (DHP) under UV irradiation in CH3CN to give aromatic products in good yields. A possible mechanism for the oxidation was suggested.展开更多
A mild, general, convenient, and efficient one-pot synthesis of 4-arylpyridines (4) is described using conventional heating, ultrasound and microwave irradiation. Aryl aldehydes (2) were efficiently condensed with eth...A mild, general, convenient, and efficient one-pot synthesis of 4-arylpyridines (4) is described using conventional heating, ultrasound and microwave irradiation. Aryl aldehydes (2) were efficiently condensed with ethylacetoacetate (1) and ammonium acetate in acetonitrile to give dihydropyridine intermediates (4). The latter underwent a smooth Iodobenzene Diacetate (III) mediated aromatization reaction in the same pot to afford 4-arylpyridines (4) in good to excellent yields.展开更多
Heterocyclic skeleton building blocks to afford dihydropyrimidinones and dihydropyridines based on neat adducts of diketene, alcohols and aldehydes via silica sulfuric acid (SSA) catalyzed ring opening of diketene i...Heterocyclic skeleton building blocks to afford dihydropyrimidinones and dihydropyridines based on neat adducts of diketene, alcohols and aldehydes via silica sulfuric acid (SSA) catalyzed ring opening of diketene in four-component Biginelli-type and Hantzsch-type reactions are presented.展开更多
Multicomponent synthesis of mono and bis 4-substituted-1,4-dihydropyridines from aldehydes,dimedone and ammonium acetate in the presence of an efficient recyclable catalyst,L-proline,in high yield and short reaction t...Multicomponent synthesis of mono and bis 4-substituted-1,4-dihydropyridines from aldehydes,dimedone and ammonium acetate in the presence of an efficient recyclable catalyst,L-proline,in high yield and short reaction time is reported.展开更多
We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in t...We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in the presence of chiral N,N′-dioxide/metal complexes.This tandem reaction enabled rapid access to versatile chiral polycyclic N-heterocycles with good to excellent enantioselectivities under mild reaction conditions in spite of the strong background reaction,including 1,2-dihydroisoquinoline,1,2-dihydropyridine derivatives,and others.Meanwhile,a series of control experiments were conducted to elucidate the reaction mechanism and the roles of additives.展开更多
A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice r...A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.展开更多
Tin dioxide (SnO2 ) nanoparticles efficiently catalyzed unsymmetrical four-component Hantzsch condensations of various aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate to form polyhydroquinoline derivativ...Tin dioxide (SnO2 ) nanoparticles efficiently catalyzed unsymmetrical four-component Hantzsch condensations of various aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate to form polyhydroquinoline derivatives in excellent yields. This novel method offers several advantages over the traditional method of synthesizing these compounds, including safety, mild conditions, short reaction times, high yields, and an easy workup.展开更多
The three-component reaction of aromatic aldehyde,malononitrile and aliphatic amine in a mixed solvent of methanol and water exhibited very interesting molecular diversity and gave the derivatives of polysubstituted N...The three-component reaction of aromatic aldehyde,malononitrile and aliphatic amine in a mixed solvent of methanol and water exhibited very interesting molecular diversity and gave the derivatives of polysubstituted N-methyldihydropyridines,2-dialkylaminopyridines and 2-methoxypyridines as main products according to the structure of aliphatic amines used.展开更多
We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds ...We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.展开更多
文摘The oxidation on 1,4-substituted Hantzsch 1,4-dihydropyridines with nitrosonium tetrafluoroborate (NO+BF4-) in acetonitrile gave Hantzsch pyridines in good yields. In some cases the dealkylation occurred. The evidences to draw the mechanism were presented.
基金the National Natural Science Foundation of China for the financial support (The grant No. 20072013)
文摘4-oxo-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy radical (TEMPO), a nitroxide, oxidized 4-substituted Hantzsch 1,4-dihydropyridines (DHP) under UV irradiation in CH3CN to give aromatic products in good yields. A possible mechanism for the oxidation was suggested.
文摘A mild, general, convenient, and efficient one-pot synthesis of 4-arylpyridines (4) is described using conventional heating, ultrasound and microwave irradiation. Aryl aldehydes (2) were efficiently condensed with ethylacetoacetate (1) and ammonium acetate in acetonitrile to give dihydropyridine intermediates (4). The latter underwent a smooth Iodobenzene Diacetate (III) mediated aromatization reaction in the same pot to afford 4-arylpyridines (4) in good to excellent yields.
文摘Heterocyclic skeleton building blocks to afford dihydropyrimidinones and dihydropyridines based on neat adducts of diketene, alcohols and aldehydes via silica sulfuric acid (SSA) catalyzed ring opening of diketene in four-component Biginelli-type and Hantzsch-type reactions are presented.
基金support from the Research Council of Islamic Azad University-Rasht Branch
文摘Multicomponent synthesis of mono and bis 4-substituted-1,4-dihydropyridines from aldehydes,dimedone and ammonium acetate in the presence of an efficient recyclable catalyst,L-proline,in high yield and short reaction time is reported.
基金the National Natural Science Foundation of China(grant no.21772127).
文摘We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in the presence of chiral N,N′-dioxide/metal complexes.This tandem reaction enabled rapid access to versatile chiral polycyclic N-heterocycles with good to excellent enantioselectivities under mild reaction conditions in spite of the strong background reaction,including 1,2-dihydroisoquinoline,1,2-dihydropyridine derivatives,and others.Meanwhile,a series of control experiments were conducted to elucidate the reaction mechanism and the roles of additives.
文摘A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.
基金the research facilities provided by the Ayatollah Amoli Branch of the Islamic Azad University
文摘Tin dioxide (SnO2 ) nanoparticles efficiently catalyzed unsymmetrical four-component Hantzsch condensations of various aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate to form polyhydroquinoline derivatives in excellent yields. This novel method offers several advantages over the traditional method of synthesizing these compounds, including safety, mild conditions, short reaction times, high yields, and an easy workup.
基金Supported by the National Natural Science Foundation of China(No.20972132)
文摘The three-component reaction of aromatic aldehyde,malononitrile and aliphatic amine in a mixed solvent of methanol and water exhibited very interesting molecular diversity and gave the derivatives of polysubstituted N-methyldihydropyridines,2-dialkylaminopyridines and 2-methoxypyridines as main products according to the structure of aliphatic amines used.
基金the National Natural Science Foundation of China(Nos.22171154 and 21801144)the Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education,the Natural Science Foundation of Shandong Province(Nos.ZR2020QB114 and ZR2020QB008)+4 种基金Jinan Science&Technology Bureau(No.2021GXRC080)supported by the Foundation(No.ZZ20190312)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology(Shandong Academy of Sciences)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,the Open Fund of the Department of Chemistry,Qingdao University of Science and Technology(No.QUSTHX202010)Science and Technology Innovation Development Plan of Yantai(No.2020MSGY114)Yantai“Double Hundred Plan”.
文摘We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.