نتایج جستجو برای: solvent free
تعداد نتایج: 560809 فیلتر نتایج به سال:
a simple and efficient method for the synthesis of quinolines and polycyclic quinolines using li+ modified nanoporous na+-montmorillonite is described. this new nanocatalyst proceeds via friedlander annulation under solvent-free conditions. it describes our observations about a trend of catalytic activity of lithium cation in nanoporous na+-montmorillonite. in this study, several types of 1,3-d...
a phosgene-free synthesis of symmetrical n,n'-disubstituted urea by the reaction of aromatic and aliphatic primary amines and urea promoted by microwave irradiation in the presence of a suitable energy-transfer solvent such as n-n-dimethylacetamide is described.
various types of aldehydes undergo crossed-aldol condensation with ketones in the presence of melamine trisulfonic acid (mtsa) under solvent-free conditions. the reported method is mild, efficient and has the advantages such as using heterogeneous catalysis, short reaction times, high yields of the products and the recyclability of the catalyst.
an efficient and environmentally friendly procedure for one-pot synthesis of 13-acetyl-9-methyl-11-ox-8-oxa-10,12-diazatricyclo [7.3.1. ] trideca-2,4,6-triene from salicylaldehyde, acetylaceton and urea via biginelli condensation and intramolecular michael-addition by using magnesium bromide as an expensive and easily available catalyst under solvent-free condition is desired. the structural el...
a mild and green method has been developed for the preparation of coumarins derivatives through the one-pot reactions. in our study,various phenols and ethyl acetoacetate compound in which we used silica-supported boron sulfonic acid [sio2/b(so4h)3] as a new, highly efficient and tri-functional inorganic brønsted acid catalyst were processed under solvent-free condition and thermal. the catalys...
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