1156-64-5Relevant academic research and scientific papers
The accelerated preparation of 1,4-dihydropyridines using microflow reactors
Baraldi, Patricia Tambarussi,No?l, Timothy,Wang, Qi,Hessel, Volker
, p. 2090 - 2092 (2014)
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.
A photocatalyst-free photo-induced denitroalkylation of β-nitrostyrenes with 4-alkyl substituted Hantzsch esters at room temperature
Duan, Chunying,Hao, Xinyu,Jin, Kun,Li, Yaming,Wang, Jiaao,Zhang, Rong,Zhang, Siyu
supporting information, (2020/02/18)
A photocatalyst-free stereoselectively photo-induced strategy for the denitroalkylation of β-nitrostyrenes using 4-alkyl substituted Hantzsch esters as the alkyl source under xenon lamp irradiation is developed. The reaction proceeds at room temperature and affords the corresponding products in moderate to excellent yields. The oxidant di-t-butyl peroxide serves as an efficient radical initiator under irradiation of a Xenon lamp, initiating alkyl radicals from the 4-alkyl substituted Hantzsch esters.
Histidine-Specific Peptide Modification via Visible-Light-Promoted C-H Alkylation
Chen, Xiaoping,Ye, Farong,Luo, Xiaosheng,Liu, Xueyi,Zhao, Jie,Wang, Siyao,Zhou, Qingqing,Chen, Gong,Wang, Ping
supporting information, p. 18230 - 18237 (2019/11/14)
Histidine (His) carries a unique heteroaromatic imidazole side chain and plays irreplaceable functional roles in peptides and proteins. Existing strategies for site-selective histidine modification predominantly rely on the N-substitution reactions of the moderately nucleophilic imidazole group, which inherently suffers from the interferences from lysine and cysteine residues. Chemoselective modification of histidine remains one of the most difficult challenges in peptide chemistry. Herein, we report peptide modification via radical-mediated chemoselective C-H alkylation of histidine using C4-alkyl-1,4-dihydropyridine (DHP) reagents under visible-light-promoted conditions. The method exploits the electrophilic reactivity of the imidazole ring via a Minisci-type reaction pathway. This method exhibits an exceptionally broad scope for both peptides and DHP alkylation reagents. Its utility has been demonstrated in a series of important peptide drugs, complex natural products, and a small protein. Distinct from N-substitution reactions, the unsubstituted nitrogen groups of the modified imidazole ring are conserved in the C-H alkylated products.
Metal free biomimetic deaminative direct C-C coupling of unprotected primary amines with active methylene compounds
Ghosh, Santanu,Jana, Chandan K.
supporting information, p. 10153 - 10157 (2019/12/26)
An unprecedented direct C-C coupling reaction of unprotected primary amines with active methylene compounds is reported. The reaction involves a biomimetic deamination of amines which was achieved under conditions free of metallic reagents and strong oxidizing agents. A wide range of primary amines was reacted with different active methylene compounds to provide structurally diverse trisubstituted alkenes and dihydropyridines. A kinetic study revealed an activation barrier of 10.1 kcal mol-1 for the conversion of a key intermediate of the reaction.
Poly(vinylimidazolum acetic acid)-entrapped nanozeolite: efficient heterogeneous catalyst for synthesis of polyhydroquinolines and 1,4-dihydropyridines
Amoli, Tabassom,Baghbanian, Seyed Meysam
, p. 3389 - 3405 (2018/02/22)
An effective method for synthesis of substituted 1,4-dihydropyridines and polyhydroquinoline derivatives by Hantzsch reaction using poly(ionic liquid)-based nanozeolite (NZ@PIL-COOH) catalyst under simple conditions is described. The new solid acid catalyst was prepared by polymerization of 3-carboxymethyl-1-vinylimidazolium in presence of modified nanozeolite, and characterized by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). The resulting heterogeneous catalyst displayed high catalytic performance under mild reaction condition in short reaction time. The catalyst was recycled eight times without any loss in reactivity or yield.
CAN mediated mechanochemical synthesis of substituted pyridine derivatives
Khanna, Radhika,Dalal, Aarti,Kadyan, Kulbir,Kumar, Ramesh,Kumar, Parvin,Kamboj, Ramesh C.
, p. 673 - 677 (2018/07/14)
A simple, green and cost-effective protocol has been devised for the synthesis of 4-substituted-2,6-dimethyl-3,5-pyridinecarboxylates from Hantzsch-type 1,4-dihydropyridines via rapid oxidation in excellent yields using 1.5 equivalent of ceric ammonium nitrate within 15 minutes in solvent-free conditions. The method was able to furnish the products in excellent yields. The products obtained were characterized by their NMR and melting points data.
Sulfated polyborate: An efficient and reusable catalyst for one pot synthesis of Hantzsch 1,4-dihydropyridines derivatives using ammonium carbonate under solvent free conditions
Rekunge, Deelip S.,Khatri, Chetan K.,Chaturbhuj, Ganesh U.
supporting information, p. 1240 - 1244 (2017/03/02)
A simple and efficient method for the synthesis of four-component 1,4-dihydropyridines of various aldehydes, β-ketoesters and ammonium carbonate catalyzed by sulfated polyborate with high yields under a solvent free condition at 90?°C is described. The key advantages of the present method are high yields, short reaction time, solvent free condition, easy workup, recyclability of catalyst and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards.
Fe3O4@SiO2 supported aza-crown ether complex cation ionic liquids: preparation and applications in organic reactions
Li, Dandan,Wang, Jinyuan,Chen, Fengjuan,Jing, Huanwang
, p. 4237 - 4242 (2017/02/05)
A series of aza-crown ether ionic liquids supported on magnetic Fe3O4@SiO2 core-shell particles were designed, synthesized and characterized by elemental analysis, TEM, TG and FT-IR. These new aza-crown ether complex cation ionic liquids were utilized as heterogeneous acidic catalysts in Friedel-Crafts alkylation and Hantzsch reaction in good yields under convenient reaction conditions. Moreover, these magnetic particle supported IL catalysts could be readily recovered by an external magnet and reused five times without obvious loss of activity.
Intermolecular [2 + 2] Cycloaddition of 1,4-Dihydropyridines with Olefins via Energy Transfer
Wang, Chengfeng,Lu, Zhan
supporting information, p. 5888 - 5891 (2017/11/10)
A highly regio- and diastereoselective visible-light-promoted [2 + 2] cycloaddition between readily available 1,4-dihydropyridines and olefins has been developed. This strategy is operationally simple and atom-economical and enables the construction of strained polysubstituted 2-azabicyclo[4.2.0]octanes with three all-carbon quaternary centers with good functional group tolerance. These products can be easily converted to various structurally unique derivatives. The primary mechanistic studies demonstrated that the reaction proceeds through an energy transfer pathway.
Benzyltrimethylammoniumfluoride Hydrate: An Efficient Catalyst for One-Pot Synthesis of Hantzsch 1,4-Dihydropyridines and Their Aromatization
Khaskel, Anamika,Barman, Pranjit
, p. 114 - 120 (2016/04/01)
An efficient, cost-effective and simple protocol has been developed for the synthesis of Hantzsch 1,4-dihydropyridines and their oxidation into pyridines using benzyltrimethylammonium fluoride hydrate as an excellent catalyst under solvent-free condition. All of the products synthesized by this method are characterized by various spectroscopic methods (IR, 1H NMR, 13C NMR, and DEPT).
