A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished via lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, α,β-ketoester and ammo...A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished via lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, α,β-ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic aldehydes affording 1,4-dihydropyridines.展开更多
The difluoromethyl-containing Hantzsch 1,4-dihydropyridines were synthesized in good yields by a one-pot cyclocondensation of ethyl difluoroacetoacetate (EDFAA),a variety of aromatic aldehydes and ammonium acetate und...The difluoromethyl-containing Hantzsch 1,4-dihydropyridines were synthesized in good yields by a one-pot cyclocondensation of ethyl difluoroacetoacetate (EDFAA),a variety of aromatic aldehydes and ammonium acetate under solvent and catalyst free conditions.The comparison of reaction conditions and products was made among the different 1,3-carbonyl substrates (ethyl acetoacetate,ethyl difluoroacetoacetate and ethyl trifluoroacetoacetate) for the Hantzsch reaction.展开更多
An efficient approach to 1,4-dihydropyridines containing novel substituted pyrazole is achieved via threecomponent reaction of pyrazolyl aldehyde, β-ketoester, and ammonium acetate in one-pot under sulfamic acid cata...An efficient approach to 1,4-dihydropyridines containing novel substituted pyrazole is achieved via threecomponent reaction of pyrazolyl aldehyde, β-ketoester, and ammonium acetate in one-pot under sulfamic acid catalysis.展开更多
An environmentally friendly and highly efficient procedure for the preparation of 1,4-dihydropyridines by the reaction between a,β-unsaturated aldehydes, aromatic amines and β-keto esters in the presence of silica s...An environmentally friendly and highly efficient procedure for the preparation of 1,4-dihydropyridines by the reaction between a,β-unsaturated aldehydes, aromatic amines and β-keto esters in the presence of silica supported perchloric acid is described.展开更多
Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies dem...Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2-·) is responsible for this typical photochemical oxidation.展开更多
An efficient and green method for the synthesis of 1, 4-dihydropyridine derivatives mediated in an ionic liquid, [bmim][BF4], through a four-component condensation process of aldehydes, 1, 3-dione, Meldrum＇s acid and...An efficient and green method for the synthesis of 1, 4-dihydropyridine derivatives mediated in an ionic liquid, [bmim][BF4], through a four-component condensation process of aldehydes, 1, 3-dione, Meldrum＇s acid and ammonium acetate is disclosed in this paper.展开更多
The Hantzsch synthesis has been used for the preparation of the 1,4-Dihydropyridines compounds with different pharmacophore groups. The use of a designed glycosylated compound in Hantzsch synthesis would lead to a nov...The Hantzsch synthesis has been used for the preparation of the 1,4-Dihydropyridines compounds with different pharmacophore groups. The use of a designed glycosylated compound in Hantzsch synthesis would lead to a novel Dihydropyridines C-Glycosylated compound. We used the 6-methoxy-2, 2-dimethyltetrahydrofuro [3, 4-d] [1, 3] dioxole-4-carbaldehyde as a glycosylated-based aldehydes. The 4-(3,4-Dihydroxy-5-methoxy-tetrahydro-furan-2-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxy-lic acid 3-ethyl ester 5-methyl ester was synthesized. The structure of compounds was determined by NMR spectroscopy, FTIR and mass spectroscopy methods. We synthesized this 1,4-Dihydropyridines compound by ionic liquid under ultrasound irradiation as a green chemistry synthesis.展开更多
A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.
文摘A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished via lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, α,β-ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic aldehydes affording 1,4-dihydropyridines.
基金supported by the National Basic Research Program of China (2010CB126101)Shanghai Foundation of Science and Technology (09391911800)+1 种基金the National High Technology Research and Development Program of China (2006AA10A201)the Shanghai Leading Academic Discipline Project (B507)
文摘The difluoromethyl-containing Hantzsch 1,4-dihydropyridines were synthesized in good yields by a one-pot cyclocondensation of ethyl difluoroacetoacetate (EDFAA),a variety of aromatic aldehydes and ammonium acetate under solvent and catalyst free conditions.The comparison of reaction conditions and products was made among the different 1,3-carbonyl substrates (ethyl acetoacetate,ethyl difluoroacetoacetate and ethyl trifluoroacetoacetate) for the Hantzsch reaction.
文摘An efficient approach to 1,4-dihydropyridines containing novel substituted pyrazole is achieved via threecomponent reaction of pyrazolyl aldehyde, β-ketoester, and ammonium acetate in one-pot under sulfamic acid catalysis.
文摘An environmentally friendly and highly efficient procedure for the preparation of 1,4-dihydropyridines by the reaction between a,β-unsaturated aldehydes, aromatic amines and β-keto esters in the presence of silica supported perchloric acid is described.
基金supported by the National Natural Science Foundation of China (20732007,20972171,50973125)the Ministry of Science and Technology of China (G2007CB808004,2009CB2 20008),and the Bureau for Basic Research of the Chinese Academy of Sciences
文摘Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2-·) is responsible for this typical photochemical oxidation.
文摘An efficient and green method for the synthesis of 1, 4-dihydropyridine derivatives mediated in an ionic liquid, [bmim][BF4], through a four-component condensation process of aldehydes, 1, 3-dione, Meldrum＇s acid and ammonium acetate is disclosed in this paper.
文摘The Hantzsch synthesis has been used for the preparation of the 1,4-Dihydropyridines compounds with different pharmacophore groups. The use of a designed glycosylated compound in Hantzsch synthesis would lead to a novel Dihydropyridines C-Glycosylated compound. We used the 6-methoxy-2, 2-dimethyltetrahydrofuro [3, 4-d] [1, 3] dioxole-4-carbaldehyde as a glycosylated-based aldehydes. The 4-(3,4-Dihydroxy-5-methoxy-tetrahydro-furan-2-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxy-lic acid 3-ethyl ester 5-methyl ester was synthesized. The structure of compounds was determined by NMR spectroscopy, FTIR and mass spectroscopy methods. We synthesized this 1,4-Dihydropyridines compound by ionic liquid under ultrasound irradiation as a green chemistry synthesis.
文摘A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.
