Facile one-pot synthesis of 5-amino-7-aryl-6-cyano-4H-pyrano[3,2-b]pyrroles using supported hydrogen sulfate ionic liquid
作者:Reza Sandaroos、Saman Damavandi、Mehri Salimi
DOI:10.1007/s00706-012-0744-2
日期:2012.12
Twelve new derivatives of 5-amino-7-aryl-6-cyano-4H-pyrano[3,2-b]pyrrole were prepared by one-pot acid-catalyzed cyclocondensation reaction of 3-hydroxypyrrole, malononitrile, and various aldehydes in the presence of the silica-supported ionic liquid 1-methyl-3-(triethoxysilylpropyl)imidazolium hydrogen sulfate as catalyst. The reaction efficiencies were enhanced by moderate electron-withdrawing groups, such Cl and Br, on benzaldehyde, but decreased as substituents became more electron-withdrawing. Among the solvents and catalysts screened for the model reaction, acetonitrile and the silica-supported hydrogen sulfate ionic liquid were found to be the best choices.