79925-38-5Relevant academic research and scientific papers
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.]
The accelerated preparation of 1,4-dihydropyridines using microflow reactors
Baraldi, Patricia Tambarussi,No?l, Timothy,Wang, Qi,Hessel, Volker
supporting information, p. 2090 - 2092 (2014/04/03)
The synthesis of 1,4-dihydropyridines was performed in a continuous-flow microreactor. Elevated temperatures accelerated the reaction rate significantly allowing the reaction to be finished in minutes (6-11 min). Different 1,4-dihydropyridines were prepared in good to excellent isolated yields (45-88% yield). The method was amenable to the preparation of daropidine, a calcium channel blocker which is currently in clinical phase 3 trials.
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.
Facile and green synthesis of 1,4-dihydropyridine derivatives in n-butyl pyridinium tetrafluoroborate
Wu, Xiao Yun
experimental part, p. 454 - 459 (2011/12/02)
l,4-Dihydropyridine derivatives were synthesized from the one-pot condensation of aldehydes, acetoacetates, and ammonium acetate in room-temperature ionic liquid n-butyl pyridinium tetrafluoroborate ([BPy][BF4]). Compared with classical Hantzsch reaction conditions, this new method has the advantage of excellent yields, short reaction time, and easy workup. The recovered ionic liquid could be recycled for at least five runs without losing its activity. Taylor & Francis Group, LLC.
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.
COMPOUNDS AND COMBINATIONS THEREOF FOR INHIBITING BETA-AMYLOID PRODUCTION AND METHODS OF USE THEREOF
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Page/Page column 135, (2010/11/29)
Provided are compounds which can be used in combination for treating diseases associated with a condition associated with cerebral accumulation of Alzheimer’s amyloid, such as Alzheimer’s disease. Also provided are methods of treating or reducing the risk of developing β-amyloid production, β-amyloid deposition, β-amyloid neurotoxicity (including abnormal hyperphosphorylation of tau) and microgliosis associated with cerebral accumulation of Alzheimer’s amyloid by administering therapeutically effective amounts of compounds which in combination can decrease β-amyloid production and capacitative calcium entry in cells. Further provided are methods for diagnosing diseases associated with cerebral accumulation of Alzheimer’s amyloid in animals or humans by administering diagnostically effective amounts of the compounds.
Process to prepare 1,4-dihydropyridine intermediates and derivatives thereof
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Page 5, (2010/02/08)
An improved catalyst is disclosed for a process involving the preparation of benzylidene intermediates useful in the preparation of 1,4-dihydropyridine compounds and derivatives thereof useful as medicines such as for example felodipine. This is accomplished by the condensation of an aldehyde and an acetoacetate in the presence of a novel catalyst system that includes a pyridyl carboxylic acid and a secondary amine. It has been found that through the use of the present invention the purity and yield of the desired isomer of the benzylidene intermediate can be maximized, thus avoiding the requirement of additional purification steps. The use of these intermediates can then be further reacted to form the required dihydropyridines, again having a very high purity and yield compared with the prior art.
PROCESS FOR THE PREPARATION OF 1,4-DIHYDROPYRIDINES AND NOVEL 1,4-DIHYDROPYRIDINES USEFUL AS THERAPEUTIC AGENTS
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Page 13; 15, (2008/06/13)
The present invention provides a process for the preparation of 1,4-dihydropyridines of the formula (1), wherein R1 is H, NO2, Cl, OAc, OH, R2 is H, NO2, Cl, -O-CH2-O-, OMe, OAc, OEt, OH, R3 is H, NO2, Cl, N(Me)2, -O- CH2 -O-, OMe, OAc, OH, R4 is H, OMe, OAc, OH, R5 is H, Cl, I, and R6 and R7 are either methyl, ethyl or both by preparing a mixture of an aromatic aldehyde, alkyl acetoacetate and a source of ammonia, adsorbing the prepared mixture and adsorbent till adsorbent becomes free flowing, heating the material so obtained under microwave irradiation, cooling the reaction mixture and recovering the compound of formula (1). The present invention also relates to novel 1,4-dihydropyridines with cardiovascular activity.
