1156-64-5Relevant articles and documents
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.
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.
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.