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
A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through im...A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through improved Biginelli reaction.展开更多
A Nation-H catalyzed, single step and environmentally friendly process for synthesis of dihydropyrimidinones is described. This adopted protocol for Biginelli reaction has the advantages of reusability of the catalyst...A Nation-H catalyzed, single step and environmentally friendly process for synthesis of dihydropyrimidinones is described. This adopted protocol for Biginelli reaction has the advantages of reusability of the catalyst, high yields and ease of separation of pure products.展开更多
An efficient and greener synthesis of a series of dihydropyrimidinone (DHPMs) derivatives were accomplished via three-component one-pot cyclocondensation between substituted aryl aldehydes, diketone/ke- toester and ur...An efficient and greener synthesis of a series of dihydropyrimidinone (DHPMs) derivatives were accomplished via three-component one-pot cyclocondensation between substituted aryl aldehydes, diketone/ke- toester and urea. This solvent free approach is totally nonpolluting having several advantages such as shorter reaction time, mild reaction conditions, simple workup and reduced environmental impact.展开更多
A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyze...A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyzed by silica-bonded S-sulfonic acid.Compared to the classical Biginelli reaction conditions,this new protocol has the advantages of consistently excellent yields and short reaction times.After the reaction,the catalyst could be recovered easily and reused with little change in its activity.展开更多
3,4-Dihydropyrimidin-2（1H）-ones （DHPMs） were oxidized with 1.2 equiv, of nitrosonium tetrafluoroborate （NO^＋BF4^-） to pyrimidin-2（1H）-ones in acetonitrile at room temperature in high yields.
An efficient and environmentally friendly procedure for the one-pot synthesis of 13-acetyl-9-methyl-ll-oxo-8-oxa-10,12-diazatricyclo[7.3.1.0^2,7]trideca-2,4,6-triene from salicylaldehyde, acetylacetone and urea via Bi...An efficient and environmentally friendly procedure for the one-pot synthesis of 13-acetyl-9-methyl-ll-oxo-8-oxa-10,12-diazatricyclo[7.3.1.0^2,7]trideca-2,4,6-triene from salicylaldehyde, acetylacetone and urea via Biginelli condensation and intramolecular Michael-addition by using magnesium bromide as an inexpensive and easily available catalyst in a solvent-free condition is described. The structural elucidation of the product is reported by ^1H- and ^13C NMR spectra. The product can also be identified by its EI TOF mass spectrometry based on the molecular ion at m/s 246（10%） and on the fragment ions in which two nitrogen atoms are remained. Three kinds of characteristic fragmentation pathways from the molecular ion were observed. One is the loss of the OH radical to form the dihydropyrimidinone cation at m/z 229（48%）, followed by elimination of a molecular methane forming the pyrimidinone cation at m/z 213（27%）. The second is the cleavage of the C6H4OH radical, and the formation of the dihydropyrimidinone cation at m/z 153（24%）. The third one is the loss of MeC-O radical to afford the oxygen-bridged fragment ion at m/z 203（33%）.展开更多
A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified on...A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.展开更多
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the National Natural Science Foundation of China(29872018&29972026).
文摘A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through improved Biginelli reaction.
文摘A Nation-H catalyzed, single step and environmentally friendly process for synthesis of dihydropyrimidinones is described. This adopted protocol for Biginelli reaction has the advantages of reusability of the catalyst, high yields and ease of separation of pure products.
文摘An efficient and greener synthesis of a series of dihydropyrimidinone (DHPMs) derivatives were accomplished via three-component one-pot cyclocondensation between substituted aryl aldehydes, diketone/ke- toester and urea. This solvent free approach is totally nonpolluting having several advantages such as shorter reaction time, mild reaction conditions, simple workup and reduced environmental impact.
基金supported by the Research Council of Payame Noor University
文摘A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyzed by silica-bonded S-sulfonic acid.Compared to the classical Biginelli reaction conditions,this new protocol has the advantages of consistently excellent yields and short reaction times.After the reaction,the catalyst could be recovered easily and reused with little change in its activity.
基金Project No.20572040 was supported by National Natural Science Foundation of China
文摘3,4-Dihydropyrimidin-2（1H）-ones （DHPMs） were oxidized with 1.2 equiv, of nitrosonium tetrafluoroborate （NO^＋BF4^-） to pyrimidin-2（1H）-ones in acetonitrile at room temperature in high yields.
基金This work was supported by the Natural Science Foundation of China （No.20425309）.
文摘An efficient and environmentally friendly procedure for the one-pot synthesis of 13-acetyl-9-methyl-ll-oxo-8-oxa-10,12-diazatricyclo[7.3.1.0^2,7]trideca-2,4,6-triene from salicylaldehyde, acetylacetone and urea via Biginelli condensation and intramolecular Michael-addition by using magnesium bromide as an inexpensive and easily available catalyst in a solvent-free condition is described. The structural elucidation of the product is reported by ^1H- and ^13C NMR spectra. The product can also be identified by its EI TOF mass spectrometry based on the molecular ion at m/s 246（10%） and on the fragment ions in which two nitrogen atoms are remained. Three kinds of characteristic fragmentation pathways from the molecular ion were observed. One is the loss of the OH radical to form the dihydropyrimidinone cation at m/z 229（48%）, followed by elimination of a molecular methane forming the pyrimidinone cation at m/z 213（27%）. The second is the cleavage of the C6H4OH radical, and the formation of the dihydropyrimidinone cation at m/z 153（24%）. The third one is the loss of MeC-O radical to afford the oxygen-bridged fragment ion at m/z 203（33%）.
文摘A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.
