Preyssler Heteropoly Acids Encapsulated in a Silica Framework for an Efficient Preparation of Fluorinated Hexahydropyrimidine Derivatives under Solvent-Free Conditions
synthesized using Preyssler heteropoly acid H14NaP5W29MoO110 encapsulated in a silica framework as the catalyst undersolvent-freeconditions. This synthesis requires short reaction times (1.5 h) and 80 °C undersolvent-freeconditions to obtain good to excellent yields of 18 hexahydropyrimidine derivatives. Preyssler catalyst embedded in the silica matrix, unlike the bulk or supported on silica, is insoluble
Green synthesis and antimicrobial evaluation of some new trifluoromethyl-substituted hexahydropyrimidines by grinding
作者:Hussein F. Zohdi、Nora M. Rateb、Sherif M. Elnagdy
DOI:10.1016/j.ejmech.2011.09.036
日期:2011.11
A series of trifluoromethyl-substituted hexahydropyrimidine derivatives were efficiently synthesized in excellent yields via one-pot three-component reaction of aromatic aldehydes, ethyl trifluoroacetoacetate and thiourea(urea) in presence of p-toluenesulfonic acid under solvent-free conditions at room temperature by grinding. The present method does not involve any hazardous organic solvent and has proven to be simple, efficient, environmentally benign and cost-effective compared with the classical synthetic methods.These compounds were screened for their antibacterial activities against Escherichia coli and Bacillus thuringiensis and found to exhibit remarkably better antibacterial activities than the control drug. (C) 2011 Elsevier Masson SAS. All rights reserved.
New Vanadium Keggin Heteropolyacids Encapsulated in a Silica Framework: Recyclable Catalysts for the Synthesis of Highly Substituted Hexahydropyrimidines Under Suitable Conditions
catalysts were determined by potentiometric titration with n-butylamine. A series of highly substituted hexahydropyrimidines were synthesized using these new materials, encapsulated in a silica framework, as catalyst in solvent-free conditions. This methodology requires short reaction time (1.5 h), a temperature of 80 °C in solvent free-conditions to obtain good to excellent yields of trifluoromethyl-hexahydropyrimidine