Artículos de revistas
First Report About the Use of Micellar Keggin Heteropolyacids as Catalysts in the Green Multicomponent Synthesis of Nifedipine Derivatives
Fecha
2016-06-24Registro en:
Palermo, Valeria; Sathicq, Angel Gabriel; Constantieux, Thierry; Rodriguez, Jean; Vazquez, Patricia Graciela; et al.; First Report About the Use of Micellar Keggin Heteropolyacids as Catalysts in the Green Multicomponent Synthesis of Nifedipine Derivatives; Springer; Catalysis Letters; 146; 9; 24-6-2016; 1634-1647
1011-372X
1572-879X
CONICET Digital
CONICET
Autor
Palermo, Valeria
Sathicq, Angel Gabriel
Constantieux, Thierry
Rodriguez, Jean
Vazquez, Patricia Graciela
Romanelli, Gustavo Pablo
Resumen
Micellar Keggin heteropolyacid catalysts were prepared using hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide—CTAB), 1-hexadecyl-pyridinium chloride, and Keggin heteropolyacids H3PMo12O40 and H4PMo11VO40 as precursors. Four catalysts were prepared (PMo12C16, PMo11VC16, PMo12C16Py, and PMo11VC16Py) and characterized by 31P NMR, FT-IR, XRD, SEM analysis and textural properties (SBET). The acidic characteristics of the catalysts were determined by potentiometric titration with n-butylamine. A series of bioactive 1,4-dihydropyridine derivatives such as nifedipine and nemadipine B were synthesized using these new materials, in a one-pot 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 1,4-dihydropyridine 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 1,4-dihydropyridines such as nitrendipine can be obtained through a sequence of steps in very good yield (78 %).