Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was des...Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
A microwave-assisted sol-gel method was employed for the preparetion of nano-sized MgO particles using Mg(NO 3)2·6H2O as precursor and deionized water as solvent.The sample calcined at 500℃ had a high specific s...A microwave-assisted sol-gel method was employed for the preparetion of nano-sized MgO particles using Mg(NO 3)2·6H2O as precursor and deionized water as solvent.The sample calcined at 500℃ had a high specific surface area of 243.2m2/g and particles sizes from 9.5to10.5nm.For comparison,MgO nanoparticles were also synthesized without microwave irradiation.X-ray diffraction (XRD) characterization showed the formation of smaller particles after microwave irradiation.The structure and morphology of the MgO particles were analyzed by N2 adsorption-desorption,XRD,scanning electron microscopy,and transmission electron microscopy.Their catalytic behavior was studied with the one-pot synthesis of Hantzsch1,4-dihydropyridines from the reaction of aromatic aldehydes,ethyl acetoacetate,and ammonium acetate.The MgO nanoparticles have high catalytic activity and gave the desired products in good to high yields.The catalyst can be easily recovered by filtration and was used at least three times with only a slight reduction in its catalytic activity.展开更多
1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodolo...1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.展开更多
A straightforward and general method has been developed for the synthesis of C5-unsubstitiuted 1,4-dihydropyridines by a reaction using dimedone, acetophenone, aromatic aldehydes, and ammonium acetate in the presence ...A straightforward and general method has been developed for the synthesis of C5-unsubstitiuted 1,4-dihydropyridines by a reaction using dimedone, acetophenone, aromatic aldehydes, and ammonium acetate in the presence of a catalytic amount of Co nanoparticles as a heterogeneous and eco-friendly catalyst with high catalytic activity at room temperature under solvent-free conditions. This catalyst is easily separated by magnetic devices and can be reused without any apparent loss of activity for the reaction. In addition, it is very interesting that when using Co nanoparticles as a catalyst, spatially-hindered aldehydes such as 2-methoxy-, 2-fluoro-, and 2-chloro-aldehydes are suitable for this reaction.展开更多
A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes,ethyl acetoacetate,and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature u...A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes,ethyl acetoacetate,and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature under solvent-free condition. This new protocol has the advantage of short reaction time and excellent yields,and is an environmentally benign route to the synthesis of 1,4-dihydropyridines.展开更多
The novel 1,2-diaryl substituted pyrrolo[3,4-b]pyridine-5,7-diones were selectively synthesized in high yields by the base catalyzed cyclization reaction of 3-arylamino-l-methyl-lH-pyrrole-2,5-diones with cinnamaldehy...The novel 1,2-diaryl substituted pyrrolo[3,4-b]pyridine-5,7-diones were selectively synthesized in high yields by the base catalyzed cyclization reaction of 3-arylamino-l-methyl-lH-pyrrole-2,5-diones with cinnamaldehyde and its derivatives in acetonitrile at room temperature. However, when piperidinium trifluoroacetate was employed as catalyst, the reaction afforded a mixture of 1,2-diaryl and 1,4-diaryl substituted pyrrolo[3,4-b]pyridine-5,7-diones in comparable yields.展开更多
文摘Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
基金supported by Islamic Azad University,Mashhad Branch
文摘A microwave-assisted sol-gel method was employed for the preparetion of nano-sized MgO particles using Mg(NO 3)2·6H2O as precursor and deionized water as solvent.The sample calcined at 500℃ had a high specific surface area of 243.2m2/g and particles sizes from 9.5to10.5nm.For comparison,MgO nanoparticles were also synthesized without microwave irradiation.X-ray diffraction (XRD) characterization showed the formation of smaller particles after microwave irradiation.The structure and morphology of the MgO particles were analyzed by N2 adsorption-desorption,XRD,scanning electron microscopy,and transmission electron microscopy.Their catalytic behavior was studied with the one-pot synthesis of Hantzsch1,4-dihydropyridines from the reaction of aromatic aldehydes,ethyl acetoacetate,and ammonium acetate.The MgO nanoparticles have high catalytic activity and gave the desired products in good to high yields.The catalyst can be easily recovered by filtration and was used at least three times with only a slight reduction in its catalytic activity.
基金supported by the Research Council of Mazandaran UniversityGorgan Medical UniversityIslamic Azad University-Ayatollah Amoli Branch for the partial support of this work
文摘1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.
基金supported by the University Grants Commission, University of Kashan
文摘A straightforward and general method has been developed for the synthesis of C5-unsubstitiuted 1,4-dihydropyridines by a reaction using dimedone, acetophenone, aromatic aldehydes, and ammonium acetate in the presence of a catalytic amount of Co nanoparticles as a heterogeneous and eco-friendly catalyst with high catalytic activity at room temperature under solvent-free conditions. This catalyst is easily separated by magnetic devices and can be reused without any apparent loss of activity for the reaction. In addition, it is very interesting that when using Co nanoparticles as a catalyst, spatially-hindered aldehydes such as 2-methoxy-, 2-fluoro-, and 2-chloro-aldehydes are suitable for this reaction.
文摘A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes,ethyl acetoacetate,and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature under solvent-free condition. This new protocol has the advantage of short reaction time and excellent yields,and is an environmentally benign route to the synthesis of 1,4-dihydropyridines.
文摘The novel 1,2-diaryl substituted pyrrolo[3,4-b]pyridine-5,7-diones were selectively synthesized in high yields by the base catalyzed cyclization reaction of 3-arylamino-l-methyl-lH-pyrrole-2,5-diones with cinnamaldehyde and its derivatives in acetonitrile at room temperature. However, when piperidinium trifluoroacetate was employed as catalyst, the reaction afforded a mixture of 1,2-diaryl and 1,4-diaryl substituted pyrrolo[3,4-b]pyridine-5,7-diones in comparable yields.
