16191-28-9Relevant academic research and scientific papers
Structure and Properties of a Five-Coordinate Nickel(II) Porphyrin
Gutzeit, Florian,Dommaschk, Marcel,Levin, Natalia,Buchholz, Axel,Schaub, Eike,Plass, Winfried,N?ther, Christian,Herges, Rainer
, p. 12542 - 12546 (2019)
Axial coordination in nickel(II) porphyrins has been thoroughly investigated and is well understood. However, isolated five-coordinate nickel(II) porphyrins are still elusive after 50 years of intense research, even though they play a crucial role as intermediates in enzymes and catalysts. Herein we present the first fully stable, thoroughly characterized five-coordinate nickel(II) porphyrin in solution and in the solid state (crystal structure). The spectroscopic properties indicate pure high-spin behavior (S = 1). There are distinct differences in the NMR, UV-vis, and redox behavior compared to those of high-spin six-coordinate [with two axial ligands, such as NiTPPF10·(py)2] and low-spin four-coordinate (NiTPPF10) nickel(II) porphyrins. The title compound, a strapped nickel(II) porphyrin, allows a direct comparison of four-, five-, and six-coordinate nickel(II) porphyrins, depending on the environment. With this reference in hand, previous results were reevaluated, for example, the switching efficiencies and thermodynamic data of nickel(II) porphyrin-based spin switches in solution.
Phosphine-free Suzuki-Miyaura reactions catalyzed by bishydrazone-Pd-complex
Mino, Takashi,Shirae, Yoshiaki,Sakamoto, Masami,Fujita, Tsutomu
, p. 882 - 884 (2003)
Glyoxal bis(methylphenylhydrazone) 1 was prepared and examined as a ligand for the Suzuki-Miyaura cross-coupling reaction of aryl bromides and arylboronic acids. We found phosphine-free catalyst, such as Pd(OAc)2/hydrazone ligand 1 to be an eff
Fast Suzuki-Miyaura cross-coupling reaction catalyzed by the Na 2Pd2Cl6 complex with ethyl calix[4]aryl acetate at room temperature in aqueous medium under ligand-free and ambient atmosphere
Mu, Bing,Li, Jingya,Han, Zixing,Wu, Yangjie
, p. 117 - 124 (2012)
The new Na2Pd2Cl6 complex with ethyl calix[4]aryl acetate 2 was prepared simply and efficiently by the extraction of sodium ion from Na2PdCl4 aqueous solution with ethyl calix[4]aryl acetate. The structure of complex 2 could be verified by X-ray single crystal structure determination. The complex 2 was tested as catalyst in Suzuki-Miyaura cross-coupling reaction at room temperature in CH 3OH/H2O medium under ambient conditions. Using 0.2 mol% of the complex 2 in the presence of K2CO3 as base offered excellent yields in the reaction of activated and non-activated aryl bromides with aryl boronic acids within 10 min. The key for achieving a very rapid and almost quantitative coupling is probably the use of ethyl calix[4]aryl acetate possessing extended hydrophobic host cavities and surface active properties. In addition, it was found that both solvent and base had a fundamental influence on the reaction.
Improving metabolic stability with deuterium: The discovery of GPU-028, a potent free fatty acid receptor 4 agonists
Li, Zheng,Xu, Xue,Li, Gang,Fu, Xiaoting,Liu, Yanzhi,Feng, Yufeng,Wang, Mingyan,Ouyang, Yunting,Han, Jing
, p. 6647 - 6652 (2017)
The free fatty acid receptor 4 (FFA4) has emerged as a promising anti-diabetic target due to its function in improvement of insulin secretion and insulin resistance. The FFA4 agonist TUG-891 revealed great potential as a widely used pharmacological tool, but it has been suffered from high plasma clearance probably because the phenylpropanoic acid is vulnerable to β-oxidation. To identify metabolically stable analog without influence on physiological mechanism of TUG-891, we tried to incorporate deuterium at the α-position of phenylpropionic acid to afford compound 4 (GPU-028). As expected, GPU-028 revealed a longer half-life (T1/2 = 1.66 h), lower clearance (CL = 0.97 L/h/kg) and higher maximum plasma concentration (Cmax = 2035.23 μg/L), resulting in a 4-fold higher exposure than TUG-891. Although GPU-028 exhibited a similar agonistic activity in comparison to TUG-891, the hypoglycemic effect of GPU-028 was better than that of TUG-891 after treatment over four weeks in diet-induced obese mice. These positive results indicated that GPU-028 might be a better pharmacological tool than TUG-891 to explore physiological function of FFA4, especially on the in vivo study.
Au-Cavitands: Size governed arene-alkyne cycloisomerization
Rusali, Lisa E.,Schramm, Michael P.
, (2020)
With an inwardly directed reactive center and a well-defined binding pocket, Au(I) functionalized resorcin[4]arene cavitands have been shown to catalyze molecular transformations. The reactivity profiles that emerge differ from other Au(I) catalysts. The added constraint of a binding pocket gives rise to the possibility that the substrates might have to fit into the resorcinarene pocket; our hypothesis is that substrates that match the available space have different reaction outcomes than those that do not. Herein we report on the intramolecular cyclization of alkyne-aromatic substrates with variable alkynes and aromatic composition. We see that scaffold size most drastically dictates reactivity, especially when the substrate's features are particularly designed. The results of these experiments add to the veritable goldmine of information about the selectivity in catalysis that cavitands offer.
Electrochemical Decarboxylative Cyclization of α-Amino-Oxy Acids to Access Phenanthridine Derivatives
Zhan, Yanling,Dai, Changhui,Zhu, Zitong,Liu, Ping,Sun, Peipei
supporting information, (2022/02/07)
Phenanthridines are a class of useful heterocycles in the field of drug development. In this work, a method via electrochemical decarboxylative cyclization of α-amino-oxy acids to access phenanthridine derivatives was developed. This reaction proceeded th
Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
, p. 5506 - 5511 (2021/07/31)
Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
Silica-coated magnetic nanoparticles functionalized cobalt complex: a recyclable and efficient catalyst for the C?C bond formation
Haqjow, Hanif,Raoufi, Farveh
, p. 4113 - 4128 (2021/07/26)
In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30?nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
A Photochemical Intramolecular C-N Coupling Toward the Synthesis of Benzimidazole-Fused Phenanthridines
Bera, Shyamal Kanti,Boruah, Palash J.,Parida, Shraddha Saraswati,Paul, Amit K.,Mal, Prasenjit
, p. 9587 - 9602 (2021/07/26)
Herein, we report a direct photochemical dehydrogenative C-N coupling of unactivated C(sp2)-H and N(sp2)-H bonds. The catalysts or additive-free transformation of 2-([1,1′-biphenyl]-2-yl)-1H-benzo[d]imidazole to benzo[4,5]imidazo[1,2-f]phenanthridine was achieved at ～350 nm of irradiation via ?-hydrogen abstraction. DFT calculations helped to understand that the N-H···πinteraction was essential for the reaction to proceed at a lower energy than expected.
Metal-Free Electrochemical Coupling of Vinyl Azides: Synthesis of Phenanthridines and β-Ketosulfones
Chen, Qianjin,Kong, Xianqiang,Li, Guodong,Liang, Qi,Lin, Long,Xu, Bo,Yu, Ke
supporting information, p. 6135 - 6145 (2020/10/06)
We reported an efficient and environmentally benign electrochemical synthesis of phenanthridines by oxidative coupling of vinyl azides with sodium azide or benzenesulfonyl hydrazides, for the first time. The reaction conditions are mild, and no additional metal-catalyst or exogenous oxidants are needed. The protocol has broad substrate scope and high functional group tolerance. Furthermore, this green electrochemical procedure can be readily extended to the synthesis of β-ketosulfones. Gram scale reactions further demonstrate the practicability.
