33421-40-8Relevant articles and documents
Mild, General, and Regioselective Synthesis of 2-Aminopyridines from Pyridine N -Oxides via N -(2-Pyridyl)pyridinium Salts
Xiong, Hui,Hoye, Adam T.
supporting information, p. 371 - 375 (2022/01/27)
A synthesis of 2-aminopyridines from pyridine N-oxides via their corresponding N-(2-pyridyl)pyridinium salts has been demonstrated and investigated. The reaction sequence features a highly regioselective conversion of the N-oxide into its pyridinium salt
Discovery and in Vivo Anti-inflammatory Activity Evaluation of a Novel Non-peptidyl Non-covalent Cathepsin C Inhibitor
Chen, Xing,Yan, Yaoyao,Zhang, Zhaoyan,Zhang, Faming,Liu, Mingming,Du, Leran,Zhang, Haixia,Shen, Xiaobao,Zhao, Dahai,Shi, Jing Bo,Liu, Xinhua
, p. 11857 - 11885 (2021/09/02)
Cathepsin C (Cat C) participates in inflammation and immune regulation by affecting the activation of neutrophil serine proteases (NSPs). Therefore, cathepsin C is an attractive target for treatment of NSP-related inflammatory diseases. Here, the complete discovery process of the first potent "non-peptidyl non-covalent cathepsin C inhibitor"was described with hit finding, structure optimization, and lead discovery. Starting with hit 14, structure-based optimization and structure-activity relationship study were comprehensively carried out, and lead compound 54 was discovered as a potent drug-like cathepsin C inhibitor both in vivo and in vitro. Also, compound 54 (with cathepsin C Enz IC50 = 57.4 nM) exhibited effective anti-inflammatory activity in an animal model of chronic obstructive pulmonary disease. These results confirmed that the non-peptidyl and non-covalent derivative could be used as an effective cathepsin C inhibitor and encouraged us to continue further drug discovery on the basis of this finding.
Synthesis of 2-guanidinyl pyridines and their trypsin inhibition and docking
Ahmed Al-Hadhrami, Nahlah,Evans, Paul,Ladwig, Angelique,Paul G. Malthouse, J.,Rahman, Adeyemi,Rozas, Isabel
supporting information, (2020/07/10)
A range of guanidine-based pyridines, and related compounds, have been prepared (19 examples). These compounds were evaluated in relation to their competitive inhibition of bovine pancreatic trypsin. Results demonstrate that compounds in which the guanidinyl substituent can form an intramolecular hydrogen bond (IMHB) with the pyridinyl nitrogen atom (6a–p) are better trypsin inhibitors than their counterparts (10–13) that are unable to form an IMHB. Among the compounds 6a–p, examples containing a 5-halo substituent were, generally, found to be better trypsin inhibitors. This trend was inversely related to electronegativity, thus, 1-(5-iodopyridin-2-yl)guanidinium ion 6e (Ki = 0.0151 mM) was the optimum inhibitor in the 5-halo series. Amongst the isomeric methyl substituted compounds, 1-(3-methylpyridin-2-yl)guanidinium ion 6h demonstrated optimum levels of trypsin inhibition (Ki = 0.0140 mM). In order to rationalise the measured enzyme inhibition, selected compounds were docked with bovine and human trypsin with a view to understanding active site occupancy and taken together with the Ki values the order of inhibitory ability suggests that the 5-halo 2-guanidinyl pyridine inhibitors form a halogen bond with the catalytically active serine hydroxy group.
Recyclable Pd/CuFe2O4 nanowires: A highly active catalyst for C-C couplings and synthesis of benzofuran derivatives
Lakshminarayana, Bhairi,Chakraborty, Jhonti,Satyanarayana,Subrahmanyam, Ch.
, p. 21030 - 21039 (2018/06/13)
Pd/CuFe2O4 nanowire-catalyzed cross coupling transformations are described. Notably, these reactions showed excellent functional group tolerance. Further, the protocol is applied to a one-pot synthesis of benzofurans via a Sonogashira coupling and intramolecular etherification sequence. The catalyst was reused and found to maintain its activity and stability.
One-Pot Palladium-Catalyzed Cross-Coupling Treble of Borylation, the Suzuki Reaction and Amination
Jong, Howard,Eey, Stanley T.-C.,Lim, Yee Hwee,Pandey, Sangeeta,Iqbal, Nurul Azmah Bte,Yong, Fui Fong,Robins, Edward G.,Johannes, Charles W.
supporting information, p. 616 - 622 (2017/02/23)
A methodology for a sequential palladium-catalyzed cross-coupling procedure consisting of borylation, the Suzuki reaction and amination has been developed for the assembly of molecules with multi-aryl backbones. The linchpin of this development is the meta-terarylphosphine ligand, Cy*Phine, which has been employed as an air- and moisture-stable precatalyst, Pd(Cy*Phine)2Cl2, to improve the efficiency of one-pot borylation–Suzuki reactions. Additionally, the reactivity of the Pd-Cy*Phine system could be tuned to furnish a one-pot, borylation–Suzuki reaction–amination (BSA) cross-coupling treble. The methodology successfully integrated complementary conditions for three distinctly different and modular reactions. Average yields of 74–94% could be achieved for each segment that cumulatively afforded 50–84% yield over the entire three-step sequence in a single pot. (Figure presented.).
Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base
Li, Zhao,Gelbaum, Carol,Campbell, Zachary S.,Gould, Paul C.,Fisk, Jason S.,Holden, Bruce,Jaganathan, Arvind,Whiteker, Gregory T.,Pollet, Pamela,Liotta, Charles L.
supporting information, p. 15420 - 15432 (2017/12/15)
The Pd-catalyzed Suzuki coupling reactions of a series of aryl chlorides and aryl bromides containing basic nitrogen centers with arylboronic acids in water in the absence of added base are reported. The reactions proceed either partially or entirely under acidic conditions. After surveying twenty-two phosphorus ligands, high yields of products were obtained with aryl chlorides only when a bulky ligand, 2-(di-tert-butyl-phosphino)-1-phenyl-1H-pyrrole (cataCXiumPtB) was used. In contrast, aryl bromides produced high yields of products in the absence of both added base and added ligand. In order to explore the Suzuki coupling process entirely under acidic conditions, a series of reactions were conducted in buffered acidic media using several model substrates. 4-Chlorobenzylamine, in the presence of cataCXiumPtB, produced high yields of product at buffered pH 6.0; the yields dropped off precipitously at buffered pH 5.0 and lower. The fall-off in yield was attributed to the decomposition of the Pd-ligand complex due to the protonation of the ligand in the more acidic aqueous media. In contrast, in the absence of an added ligand, 4-amino-2-chloropyridine produced quantitative yields at buffered pH 3.5 and 4.5 while 4-amino-2-bromopyridine produced quantitative yields in a series of buffered media ranging from pH 4.5 to 1.5. These substrates are only partially protonated in acidic media and can behave as active Pd ligands in the Suzuki catalytic cycle.
METHODS FOR EXTERNAL BASE-FREE SUZUKI COUPLINGS
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Paragraph 0040-0041, (2017/07/14)
The present disclosure describes a method of coupling a first aromatic compound to a second aromatic compound, the method comprising: (a) preparing a reaction mixture comprising the first aromatic compound, the second aromatic compound, a catalyst and water; the reaction mixture does not contain an external base, the reaction mixture having an initial pH of from 11 to 1; the catalyst having at least one group 10 atom; the first aromatic compound having a halogen, triflate or sulfonate substituent; the second aromatic compound having a boron-containing substituent; wherein, at least one of the first aromatic compound or the second aromatic compound includes one or more heteroatom; and (b) reacting the first aromatic compound and the second aromatic compound in the reaction mixture, the reaction mixture having a final pH following reaction of the first aromatic compound and the second aromatic compound.
Novel cyclodextrin-modified h-BN@Pd(II) nanomaterial: An efficient and recoverable catalyst for ligand-free C-C cross-coupling reactions in water
Ma, Xiaojun,Lv, Guanghui,Cheng, Xu,Li, Weijian,Sang, Rui,Zhang, Yong,Wang, Qiantao,Hai, Li,Wu, Yong
, (2017/10/05)
An environmentally friendly palladium(II) catalyst supported on cyclodextrin-modified h-BN was successfully prepared. The catalyst was characterized by FT-IR, SEM, TG, XRD and XPS, and the loading level of Pd in h-BN@β-CD@Pd(II) was measured to be 0.088?mmol g?1 by ICP. It exhibits excellent catalytic activity for the Suzuki and Heck reactions in water, and can be easily separated and consecutively reused for at least nine times. In addition, a series of pharmacologically interesting products were successfully synthesized using this catalyst to demonstrate its potential applications in pharmaceutical industries. Above all, this work opens up an interesting and attractive avenue for the use of cyclodextrin-functionalized h-BN as an efficient support for hydrophilic heterogeneous catalysts.
Ligand-Free C–C Coupling Reactions Promoted by Hexagonal Boron Nitride-Supported Palladium(II) Catalyst in Water
Cheng, Xu,Li, Weijian,Nie, Ruifang,Ma, Xiaojun,Sang, Rui,Guo, Li,Wu, Yong
supporting information, p. 454 - 466 (2017/02/10)
A micron-scale palladium(II) material has been successfully prepared using Schiff base-modified hexagonal boron nitride as a support and used for the first time as an efficient and recyclable catalyst in organic synthesis. The morphology, composition, metal loading and thermal stability of the catalyst were studied using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), infrared spectroscopy (FT-IR), inductively coupled plasma (ICP) and thermogravimetric (TG) analyses. Then, the micron material was tested in various C–C cross-coupling reactions and exhibited excellent catalytic activities in the Suzuki and Heck reactions. Moreover, the catalyst could be easily recovered by simple filtration and reused at least ten times without significant loss of its catalytic activity. In general, this work demonstrates the possibility of using Schiff-base@hexagonal boron nitride as an efficient support for heterogeneous catalysts. (Figure presented.).
PROCESS FOR THE CATALYTIC DIRECTED CLEAVAGE OF AMIDE-CONTAINING COMPOUNDS
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Page/Page column 51; 54, (2017/04/11)
The present invention relates to a catalytic method for the conversion of amide-containing compouds by means of a build-in directing group and upon the action of a heteronucleophilic compound (in se an amine (RNH2 or RNHR') or an alcohol (ROH) or a thiol (RSH)) in the presence of a metal catalyst to respectively esters, thioesters, carbonates, thiocarbonates and to what is defined as amide-containing compounds (such as carboxamides, urea, carbamates, thiocarbamates). The present invention also relates to these amide-containing compounds having a build-in directing group (DG), as well as the use of such directing groups in the catalytic directed cleavage of N-DG amides with the use of heteronucleophiles (in se an amine (RNH2 or RNHR') or an alcohol (ROH) or thiol (RSH)).
