79925-38-5Relevant articles and documents
First Report About the Use of Micellar Keggin Heteropolyacids as Catalysts in the Green Multicomponent Synthesis of Nifedipine Derivatives
Palermo, Valeria,Sathicq, ángel G.,Constantieux, Thierry,Rodríguez, Jean,Vázquez, Patricia G.,Romanelli, Gustavo P.
, p. 1634 - 1647 (2016/08/30)
Abstract: 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?%). Graphical Abstract: [Figure not available: see fulltext.]
Light induced synthesis of symmetrical and unsymmetrical dihydropyridines in ethyl lactate-water under tunable conditions
Ghosh, Partha Pratim,Paul, Sanjay,Das, Asish R.
, p. 138 - 142 (2013/02/21)
A highly efficient environment-friendly one-pot green methodology has been developed for the synthesis of symmetrical and unsymmetrical 1,4-dihydropyridines and polyhydroquinolines following the multicomponent Hantzsch synthesis under visible light irradiation in ethyl-l-lactate-water solution at room temperature. The present methodology offers several advantages such as simple procedure, greener condition, excellent yields and short reaction time sans any catalyst, support or promoter. The developed protocol has been materialized with the involvement of a household compact tungsten lamp as the visible light source, and the manifested high selectivity of the reaction performed in ethyl lactate-water solvent mixture under tunable conditions. The Ca2+ channel blocker nitrendipine and nemadipine B were also successfully synthesized applying the developed methodology in high yields.
A new In-SiO2 composite catalyst in the solvent-free multicomponent synthesis of Ca2+ channel blockers nifedipine and nemadipine B
Affeldt, Ricardo F.,Benvenutti, Edilson V.,Russowsky, Dennis
experimental part, p. 1502 - 1511 (2012/07/30)
An In-SiO2 composite was prepared by the sol-gel method and was applied as a heterogeneous Lewis acid catalyst in the multicomponent Hantzsch synthesis of symmetrical and non-symmetrical 1,4-DHPs. The Ca2+ channel blockers nifedipine and nemadipine B were synthesized in a single step through a solvent-free protocol. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
