35047-29-1Relevant articles and documents
Kinetics and Mechanism of the Nickel(II)- and Copper(II)- promoted Reduction of Di-2-pyridyl Ketone with Sodium Tetrahydroborate
Suh, Myunghyun Paik,Kwak, Chee-Hun,Suh, Junghun
, p. 1165 - 1166 (1991)
The kinetics of reduction of di-2-pyridyl ketone with NaBH4 leading to the formation of di-2-pyridylmethanol (dpm) was studied in the presence of Ni(II) or Cu(II).The metal ion-promoted reduction involved two successive intermediates.Based on the visible spectra and kinetic data concerning the intermediates, it is proposed that the first intermediate is (nickel(I) or copper(I) complex of the anion of dpm and that the second intermediate is the corresponding complex of dpm.
Higher MLCT lifetime of carbene iron(ii) complexes by chelate ring expansion
Bauer, Matthias,Heinze, Katja,Kruse, Ayla,Lochbrunner, Stefan,Reuter, Thomas,Schoch, Roland
, p. 7541 - 7544 (2021)
Combining strong σ-donating N-heterocyclic carbene ligands and π-accepting pyridine ligands with a high octahedricity in rigid iron(ii) complexes increases the3MLCT lifetime from 0.15 ps in the prototypical [Fe(tpy)2]2+complex to 9.2 ps in [Fe(dpmi)2]2+12+. The tripodal CNN ligand dpmi (di(pyridine-2-yl)(3-methylimidazol-2-yl)methane) forms six-membered chelate rings with the iron(ii) centre leading to close to 90° bite angles and enhanced iron-ligand orbital overlap.
Light-driven MPV-type reduction of aryl ketones/aldehydes to alcohols with isopropanol under mild conditions
Cao, Dawei,Xia, Shumei,Pan, Pan,Zeng, Huiying,Li, Chao-Jun,Peng, Yong
supporting information, p. 7539 - 7543 (2021/10/12)
Alcohols are versatile structural motifs of pharmaceuticals, agrochemicals and fine chemicals. With respect to green chemistry, the development of more sustainable and cost-efficient processes for converting ketones/aldehydes to alcohols is highly desired. Herein, a direct light-driven strategy for reducing ketones/aldehydes to alcohols using isopropanol as the reducing agent and solvent, in the presence of t-BuOLi, under an air atmosphere at room temperature is developed. This operationally simple light-promoted Meerwein-Ponndorf-Verley (MPV) type reduction can be used to produce various benzylic alcohol derivatives as well as applied to bioactive molecules and PEEK model compounds, demonstrating its application potential.
Complex for catalyzing polymerization of 4-methyl-1-pentene and preparation method thereof
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Paragraph 0037-0039, (2020/07/02)
The invention discloses a complex for catalyzing polymerization of 4-methyl-1-pentene and a preparation method thereof. According to the complex, di (pyridine-2-yl) methyl with large steric hindranceis introduced into the ortho-position of an imine nitrogen atom aromatic ring. The bis (pyridine-2-yl) methyl with large steric hindrance is introduced, a steric effect is provided, aniline aromatic ring rotation can be inhibited during catalytic polymerization, and a metal center is effectively shielded and thus the metal center is protected. Besides, an electron withdrawing effect is provided, the electrophilicity of the metal active center is enhanced, monomer insertion is facilitated during catalytic polymerization, and the catalytic activity of the catalyst is improved; the prepared pyridine-imine palladium catalyst is novel in structure and has good thermal stability and catalytic activity in catalyzing polymerization of 4-methyl-1-pentene.
Ruthenium complexes with PYA pincer ligands for catalytic transfer hydrogenation of challenging substrates
Melle, Philipp,Albrecht, Martin
, p. 299 - 303 (2019/07/08)
Here we highlight the potential of a series of ruthenium complexes with tridentate N,N,N pincer-type ligands featuring two pyridylidene amide (PYA) moieties in the ligand skeleton. They were successfully applied in transfer hydrogenation of ketones and C=C double bonds. Rational ligand design was key for increasing the catalytic performance in the reduction of challenging substrates such as potentially chelating acetylpyridines. The specific reaction profiles indicate catalyst poisoning via imine coordination as well as N,O-bidentate coordination of the substrate or the product. Approaches to mitigate this inhibition are presented. Furthermore, these PYA pincer ruthenium complexes accomplish the selective reduction of the C=C over C=O bond of α,β-unsaturated ketones such as benzylideneacetone, while other α,β-unsaturated ketones such as trans-chalcone predominantly underwent oxidative C=C bond cleavage.
Carbohydrate-functionalized N-heterocyclic carbene Ru(ii) complexes: Synthesis, characterization and catalytic transfer hydrogenation activity
Byrne, Joseph P.,Musembi, Pauline,Albrecht, Martin
, p. 11838 - 11847 (2019/08/13)
Three Ru complexes containing carbohydrate/N-heterocyclic carbene hybrid ligands were synthesized that were comprised of a triazolylidene coordination site and a directly linked per-acetylated glucosyl (5Glc) or galactosyl unit (5Gal), or a glycosyl unit linked through an ethylene spacer (6). Electrochemical and UV-vis analysis indicate only minor perturbation of the electronic configuration of the metal center upon carbohydrate installation. Deprotection of the carbohydrate was accomplished under basic conditions to afford complexes that were stable in solution over several hours, but decomposed in the solid state. Complexes 5 and 6 were used as pre-catalysts for transfer hydrogenation of ketones under basic conditions, i.e. conditions that lead to in situ deprotection of the carbohydrate entity. The carbohydrate directly influences the catalytic activity of the metal center. Remotely linked carbohydrates (complex 6) induce significantly lower catalytic activity than directly linked carbohydrates (complexes 5Glc, 5Gal), while unfunctionalized triazolylidenes are an order of magnitude more active. These observations and substrate variations strongly suggest that substrate bonding is rate-limiting for transfer hydrogenation in these hybrid carbohydrate/triazolylidene systems.
Development of dipyridine-based coordinative polymers for reusable heterogeneous catalysts
Chang, Hsiang-Chun,Li, Jia-Qi,Lin, Ching-Kai,Hsu, Yu-Jung,Tu, Tsung-Han,Hsieh, Yi-Liang,Hsu, Hsiu-Hao,Lee, Gene-Hsiang,Liu, Yi-Hung,Peng, Chi-How
, p. 1119 - 1133 (2019/08/01)
Poly(di(pyridin-2-yl)methyl acrylate) (PDPyMA), which was obtained by the free radical polymerization of designed coordinative monomer of di(pyridin-2-yl)methyl acrylate, is able to coordinate with various metal ions to form heterogeneous catalysts for diverse catalytic reactions. The Pd and Cu complexes supported by PDPyMA were developed for the heterogeneous Suzuki-Miyaura reaction and Friedel-Crafts alkylation, respectively. The PDPyMA-based catalysts showed no significant decline of reactivity after five times recycling. However, the hydrolysis of the PDPyMA backbone under alkaline conditions limited the catalytic efficiency of this heterogeneous catalyst so that the coordinative monomer was redesigned as 1,1-di(pyridine-2-yl)-2-(4-vinylphenyl)ethan-1-ol and then 2,2′-(1-methoxy-2-(4-vinylphenyl)ethane-1,1-diyl)dipyridine (MVPhDPy). With copolymerization of N-isopropyl acrylamide (NIPAM), the efficiency of polymer-based heterogeneous catalysts could be further raised, demonstrated by the increased turn over number in the Suzuki-Miyaura reaction, which approached 5,260 by using the catalyst formed from poly(MVPhDPy-co-NIPAM) and Pd(OAc)2. poly(MVPhDPy-co-NIPAM) copolymer, therefore, could be a versatile platform to support different metal ions for various heterogeneous catalytic reactions.
CRYSTALLINE FORMS OF 4-(1-(1,1-DI(PYRIDIN-2-YL)ETHYL)-6-(3,5-DIMETHYLISOXAZOL-4-YL)-1H- PYRROLO[3,2-B]PYRIDIN-3-YL)BENZOIC ACID THAT INHIBITS BROMODOMAIN
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Paragraph 0134, (2018/10/19)
Forms of 4-(1-(1,1-di(pyridin-2-yl)ethyl)-6-(3,5-dimethylisoxazol-4-yl)-1H-pyrrolo[3,2-b]pyridin-3-yl)benzoic acid were prepared and characterized in the solid state: Compound I. Also provided are processes of manufacture and methods of using the forms of Compound I.
Modular Pincer-type Pyridylidene Amide Ruthenium(II) Complexes for Efficient Transfer Hydrogenation Catalysis
Melle, Philipp,Manoharan, Yanisha,Albrecht, Martin
, p. 11761 - 11774 (2018/09/21)
A set of bench-stable ruthenium complexes with new N,N,N-tridentate coordinating pincer-type pyridyl-bis(pyridylideneamide) ligands was synthesized in excellent yields, with the pyridylidene amide in meta or in para position (m-PYA and p-PYA, respectively). While complex [Ru(p-PYA)(MeCN)3]2+ is catalytically silent in transfer hydrogenation, its meta isomer [Ru(m-PYA)(MeCN)3]2+ shows considerable activity with turnover frequencies at 50% conversion TOF50 = 100 h-1. Spectroscopic, electrochemical, and crystallographic analyses suggest considerably stronger donor properties of the zwitterionic m-PYA ligand compared to the partially π-acidic p-PYA analogue, imparted by valence isomerization. Further catalyst optimization was achieved by exchanging the ancillary MeCN ligands with imines (4-picoline), amines (ethylenediamine), and phosphines (PPh3, dppm, dppe). The most active catalyst was comprised of the m-PYA pincer ligand and PPh3, complex [Ru(m-PYA)(PPh3)(MeCN)2]2+, which reached a TOF50 of 430 h-1 under aerobic conditions and up to 4000 h-1 in the absence of oxygen. The presence of oxygen reversibly deactivates the catalytically active species, which compromises activity, but not longevity of the catalyst. Ligand exchange kinetic studies by NMR spectroscopy indicate that the strong trans effect of the phosphine is critical for high catalyst activity. Diaryl, aryl-alkyl, and dialkyl ketones were hydrogenated with high conversion, and α,β-unsaturated ketones produced selectively the saturated ketone as the only product due to exclusive C=C bond hydrogenation, a distinctly different selectivity from most other transfer hydrogenation catalysts.
N-Arylamines Coupled with Aldehydes, Ketones, and Imines by Means of Photocatalytic Proton-Coupled Electron Transfer
Xia, Qing,Tian, Hao,Dong, Jianyang,Qu, Yi,Li, Lili,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
supporting information, p. 9269 - 9273 (2018/06/04)
A photoredox-catalyzed umpolung strategy for coupling reactions between aldehydes, ketones, imines, and N-arylamines is reported. These reactions proceed by a Br?nsted acid-activated proton-coupled electron transfer pathway, and the protocol was used to synthesize a broad scope of 1,2-amino alcohols and vicinal diamines, both of which are common motifs in biologically active natural products, pharmaceutically active molecules, and ligands.
