An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advanta...An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.展开更多
Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reac...Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.展开更多
An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The...An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.展开更多
The acid-base equilibrium of 1,10-phenanthroline (1,10-phen) in the presence of polyethylene glycol 400 (PEG-400, non-ionic) and tetrabutylammonium bromide (TBAB, ionic) micellar media has been studied by Calvin-Wilso...The acid-base equilibrium of 1,10-phenanthroline (1,10-phen) in the presence of polyethylene glycol 400 (PEG-400, non-ionic) and tetrabutylammonium bromide (TBAB, ionic) micellar media has been studied by Calvin-Wilson titration technique at different mole fractions (0.5% - 2.5%) of PEG-400 and TBAB micellar solutions at an ionic strength of 0.16 mol dm-3 NaCl and at a temperature of 298 K. The pH metric data were subjected to SCPHD program to obtain correction factor and Kw which were given as initial inputs for MINIQUAD75 program to refine protonation constants. HySS program was then used to generate the species distribution diagrams versus pH using the results obtained from the MINIQUAD75 program and SIM run data. The difference in values of protonation constants in aqueous medium (logβ1 = 4.93 & logβ2 = 6.22) and in the micellar media (PEG-400, logβ1 = 4.89 & logβ2 = 5.91 and TBAB, logβ1 = 4.84 & logβ2 = 5.73) is attributed to different intrinsic solvent characteristics of micelles. In case of ionic surfactants, the electrostatic micellar surface is an additional contributing factor.展开更多
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061-A25-019)the Scientific Research Fund of Gansu Provincial Education Department(No.0601-25).
文摘An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.
基金supported by the Natural Science Foundation of China(No.20272047,20572086)the Gansu Natural Science Foundation of China(No.0308RJZA-100)Key Laboratory of Eco-Environment-Related Polymer Material(Northwest Normal University),Ministry of the Education of China
文摘Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061- A25-019)the Scientific Research fund of Gansu Provincial Education Department(No.0601-25)
文摘An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.
文摘The acid-base equilibrium of 1,10-phenanthroline (1,10-phen) in the presence of polyethylene glycol 400 (PEG-400, non-ionic) and tetrabutylammonium bromide (TBAB, ionic) micellar media has been studied by Calvin-Wilson titration technique at different mole fractions (0.5% - 2.5%) of PEG-400 and TBAB micellar solutions at an ionic strength of 0.16 mol dm-3 NaCl and at a temperature of 298 K. The pH metric data were subjected to SCPHD program to obtain correction factor and Kw which were given as initial inputs for MINIQUAD75 program to refine protonation constants. HySS program was then used to generate the species distribution diagrams versus pH using the results obtained from the MINIQUAD75 program and SIM run data. The difference in values of protonation constants in aqueous medium (logβ1 = 4.93 & logβ2 = 6.22) and in the micellar media (PEG-400, logβ1 = 4.89 & logβ2 = 5.91 and TBAB, logβ1 = 4.84 & logβ2 = 5.73) is attributed to different intrinsic solvent characteristics of micelles. In case of ionic surfactants, the electrostatic micellar surface is an additional contributing factor.
