- Synthesis and electronic properties of π-extended flavins
-
Flavin derivatives with an extended π-conjugation were synthesized in moderate to good yields from aryl bromides via a Buchwald-Hartwig palladium catalyzed amination protocol, followed by condensation of the corresponding aromatic amines with violuric acid. The electronic properties of the new compounds were investigated by absorption and emission spectroscopy, cyclic voltammetry, density functional theory (DFT) and time dependent density functional theory (TDDFT). The compounds absorb up to 550 nm and show strong luminescence. The photoluminescence quantum yields PL measured in dichloromethane reach 80% and in PMMA (poly(methyl methacrylate)) 77%, respectively, at ambient temperature. The electrochemical redox behaviour of π-extended flavins follows the mechanism previously described for the parent flavin.
- Mataranga-Popa,Torje,Ghosh,Leitl,Sp?th,Novianti,Webster,K?nig
-
-
Read Online
- Mechanistic Insights into the FeCl3-Catalyzed Oxidative Cross-Coupling of Phenols with 2-Aminonaphthalenes
-
The selective FeCl3-catalyzed oxidative cross-coupling reaction between phenols and primary, secondary, and tertiary 2-aminonaphthalene derivatives was investigated. The generality of this scalable method provides a sustainable alternative for preparing N,O-biaryl compounds that are widely used as ligands and catalysts. Based on a comprehensive kinetic investigation, a catalytic cycle involving a ternary complex that binds to both the coupling partners and the oxidant during the key oxidative coupling step is postulated. Furthermore, the studies showed that the reaction is regulated by off-cycle acid-base and ligand exchange processes.
- Vershinin, Vlada,Forkosh, Hagit,Ben-Lulu, Mor,Libman, Anna,Pappo, Doron
-
-
- Mono/Dual Amination of Phenols with Amines in Water
-
We herein describe a practical direct amination of phenols through a palladium-catalyzed hydrogen-transfer-mediated activation method to synthesize the secondary and tertiary amines. In this conversion, environmentally friendly water and inexpensive ammonium formate were used as solvent and reductant, respectively. A range of amines, including aliphatic amines, aniline, secondary amines, and diamines, could be coupled effectively by this method to achieve mono/dual amination and cyclization of phenols. This study not only provides a green and mild strategy for the synthesis of secondary and tertiary naphthylamines but also expands the synthesis of chloroquine in organic chemistry.
- Liang, Wanyi,Xie, Feng,Yang, Zhihai,Zeng, Zheng,Xia, Chuanjiang,Li, Yibiao,Zhu, Zhongzhi,Chen, Xiuwen
-
supporting information
p. 8291 - 8295
(2020/10/12)
-
- PREPARATION OF SECONDARY AMINES WITH ELECTROPHILIC N-LINCHPIN REAGENTS
-
In one aspect, the present disclosure provides methods of preparing a secondary amine. In some embodiments, the secondary amine comprises two different groups or two identifical groups. Also provided herein are compositions for use in the preparation of the secondary amine.
- -
-
Page/Page column 101-102
(2018/12/13)
-
- Practical Singly and Doubly Electrophilic Aminating Agents: A New, More Sustainable Platform for Carbon-Nitrogen Bond Formation
-
Given the importance of amines in a large number of biologically active natural products, active pharmaceutical ingredients, agrochemicals, and functional materials, the development of efficient C-N bond-forming methods with wide substrate scope continues to be at the frontier of research in synthetic organic chemistry. Here, we present a general and fundamentally new synthetic approach for the direct, transition-metal-free preparation of symmetrical and unsymmetrical diaryl-, arylalkyl-, and dialkylamines that relies on the facile single or double addition of readily available C-nucleophiles to the nitrogen atom of bench-stable electrophilic aminating agents. Practical single and double polarity reversal (i.e., umpolung) of the nitrogen atom is achieved using sterically and electronically tunable ketomalonate-derived imines and oximes. Overall, this novel approach represents an operationally simple, scalable, and environmentally friendly alternative to transition-metal-catalyzed C-N cross-coupling methods that are currently used to access structurally diverse secondary amines.
- Kattamuri, Padmanabha V.,Yin, Jun,Siriwongsup, Surached,Kwon, Doo-Hyun,Ess, Daniel H.,Li, Qun,Li, Guigen,Yousufuddin, Muhammed,Richardson, Paul F.,Sutton, Scott C.,Kürti, László
-
supporting information
p. 11184 - 11196
(2017/08/21)
-
- THERAPEUTIC AGENT FOR HEPATITIS C
-
This invention provides a therapeutic agent for hepatitis C comprising, as an active ingredient, a compound having anti-HCV activity useful in treatment of hepatitis C. The therapeutic agent for hepatitis C comprises, as an active ingredient, a compound represented by formula (I) or a pharmaceutically acceptable salt thereof.
- -
-
Page/Page column 22
(2013/02/27)
-
- Nickel-catalyzed amination of aryl phosphates through cleaving aryl C-O bonds
-
The amination of triaryl phosphates was achieved using a Ni(II)-(σ-Aryl) complex/NHC catalyst system in dioxane at 110 °C in the presence of NaH as base. Electron-neutral, -rich, and -deficient triaryl phosphates were coupled with a wider range of amine partners including cyclic and acyclic secondary amines, aliphatic primary amines, and anilines in good to excellent yields.
- Huang, Jin-Hua,Yang, Lian-Ming
-
supporting information; experimental part
p. 3750 - 3753
(2011/09/14)
-
- Cu-catalyzed carbon-heteroatom coupling reactions under mild conditions promoted by resin-bound organic ionic bases
-
Resin-bound organic ionic bases (RBOIBs) were developed in which tetraalkyl-ammonium or phosphonium cations are covalently attached to solid resins. The application tests showed that the performance of the tetraalkyl-ammonium-type RBOIBs is slightly better than that of the corresponding Cs salts in Cu-catalyzed C-N cross-couplings, while the tetraalkylphosphonium-type RBOIBs are significantly better than all the inorganic bases. With these newly developed RBOIBs, room-temperature Cu-catalyzed C-Ncoupling with various nonactivated aryl iodides and even aryl bromides can be readily accomplished. Moreover, RBOIBs can be easily recycled and reused for a number of times without much drop of activity. The good performances of RBOIBs are proposed to arise from the relatively weak binding forces between the cationic polymer backbone and basic anions, as opposed to the strong metal-anion interactions in the inorganic bases. Further applications of RBOIBs in Ni-catalyzed Suzuki-type couplings at room temperature, Cu-catalyzed C-N couplings at -30 °C, a Pd-catalyzed Heck reaction at 60 °C, and Cu-catalyzed C-S couplings at room temperature demonstrate that RBOIBs are generally applicable bases with improved performance for many other types of organic transformations.
- Huang, Yao-Bing,Yang, Chu-Ting,Yi, Jun,Deng, Xiao-Jian,Fu, Yao,Liu, Lei
-
experimental part
p. 800 - 810
(2011/04/22)
-
- Structural development studies of anti-hepatitis C virus agents with a phenanthridinone skeleton
-
A phenanthridinone skeleton was derived from our previous researches on thalidomide and retinoids as a multi-template for generation of anti-viral lead compounds. Structural development studies focusing on anti-hepatitis C virus activity afforded 5-butyl-2-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)phenanthridin-6(5H)-one (10) and 5-butylbenzo[b]phenanthridin-6(5H)-one (39), which showed EC50 values of approximately 3.7 and 3.2 μM, respectively.
- Nakamura, Masahiko,Aoyama, Atsushi,Salim, Mohammed T.A.,Okamoto, Mika,Baba, Masanori,Miyachi, Hiroyuki,Hashimoto, Yuichi,Aoyama, Hiroshi
-
experimental part
p. 2402 - 2411
(2010/06/20)
-
- Stable triazenes derived from 2-alkylaminonaphthalenes and 5-nitrobenzo[c]-1,2-thiazole-3-diazonium hydrogensulfate
-
A calculation using the DFT method confirmed that the extraordinary stability of the triazenes formed by an azo coupling reaction of 5-nitrobenzo[c]-1,2-thiazole-3-diazonium with primary or secondary aromatic amines is caused by the fact that these substances are protonated at the heterocyclic nitrogen atom and not at the nitrogen atom of the triazene grouping -N=N-N(R)Ar. Stable triazenes are also formed by reaction of 5-nitrobenzo[c]-1,2-thiazole-3-diazonium with 2-alkylaminonaphthalenes. In the cases of the azo coupling reaction with 2-methylamino- and 2- ethylaminonaphthalene, the content of triazenes is almost 50% in the product mixture with the isomeric azo compounds. The structures of the triazenes were confirmed by X-ray analysis. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Prikryl, Josef,Machacek, Vladimir,Jansa, Petr,Svobodova, Marketa,Ruzicka, Ales,Nachtigall, Petr,Cerny, Michal
-
experimental part
p. 3272 - 3278
(2009/04/06)
-