Authors: Valeria Palermo Ángel G Sathicq Thierry Constantieux Jean Rodríguez Patricia G Vázquez Gustavo P Romanelli
Publish Date: 2016/06/24
Volume: 146, Issue: 9, Pages: 1634-1647
Abstract
Micellar Keggin heteropolyacid catalysts were prepared using hexadecyltrimethylammonium bromide cetyltrimethylammonium bromide—CTAB 1hexadecylpyridinium chloride and Keggin heteropolyacids H3PMo12O40 and H4PMo11VO40 as precursors Four catalysts were prepared PMo12C16 PMo11VC16 PMo12C16Py and PMo11VC16Py and characterized by 31P NMR FTIR XRD SEM analysis and textural properties SBET The acidic characteristics of the catalysts were determined by potentiometric titration with nbutylamine A series of bioactive 14dihydropyridine derivatives such as nifedipine and nemadipine B were synthesized using these new materials in a onepot procedure in ethanol This methodology requires a reaction time of 8 h and a temperature of 78 °C to obtain good to excellent yields of 14dihydropyridine derivatives The micellar Keggin catalysts are insoluble in polar media which allows easy removal of the reaction products without affecting their catalytic activity The leaching test showed that they have an excellent stability and can be used five times as heterogeneous catalysts without appreciable loss of the catalytic activity Using the same material unsymmetrical 14dihydropyridines such as nitrendipine can be obtained through a sequence of steps in very good yield 78 The authors thank G Valle for FTIR spectra M Theiller for the SEM analysis E Soto for SBET data and F Ziarelli for 31PNMR spectra This work was supported by CONICET PIP 003 ANPCyT PICT 20130409 UNLP Centre National de la Recherche Scientifique CNRS and the Université Paul Cézanne d’AixMarseille VP AGS PGV and GPR are members of CONICET
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