2202-79-1Relevant academic research and scientific papers
Oxidative dehydrogenation and the aromatization of polycycles using o-iodoxybenzoic acid (IBX)
Kotha, Sambasivarao,Banerjee, Shaibal,Mandal, Kalyaneswar
, p. 2043 - 2045 (2004)
An efficient and convenient method for the dehydrogenation and aromatization of various polycycles using o-iodoxybenzoic acid (IBX) is described.
Trinuclear Mn(ii) complex with paramagnetic bridging 1,2,3-dithiazolyl ligands
Sullivan, David J.,Clerac, Rodolphe,Jennings, Michael,Lough, Alan J.,Preuss, Kathryn E.
, p. 10963 - 10965 (2012)
The first metal coordination complex of a radical ligand based on the 1,2,3-dithiazolyl heterocycle is reported. 6,7-Dimethyl-1,4-dioxo-naphtho[2,3-d] [1,2,3]dithiazolyl acts as a bridging ligand in the volatile trinuclear Mn(hfac)2-Rad-Mn(hfac)2-Rad-Mn(hfac)2 complex (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-). The Mn(ii) and radical ligand spins are coupled anti-ferromagnetically (AF) resulting in an ST = 13/2 spin ground state.
Photosensitization of Fluorofuroxans and Its Application to the Development of Visible Light-Triggered Nitric Oxide Donor
Seymour, Christopher Peter,Tohda, Rei,Tsubaki, Motonari,Hayashi, Masahiko,Matsubara, Ryosuke
, p. 9647 - 9654 (2017)
Nitric oxide (NO) is an endogenous signaling molecule used in multiple biochemical processes. The development of switchable NO donors that deliver an NO payload under spatiotemporal control harbors many medicinal benefits. Previously, 4-fluorofuroxans were found to function as a UV light-induced NO donor under physiological conditions based on the photoinduced isomerization mechanism; however, the isomerization of fluorofuroxans with longer wavelength light is desired for further application into living systems. Herein, we report the use of photosensitizers in the photochemical isomerization of fluorofuroxan, enabling the use of visible light to induce isomerization. Among the tried photosensitizers, anthraquinone derivatives showed a good sensitizing ability to isomerize 4-fluorofuroxan to 3-fluorofuroxan using visible light. This new phenomenon was applied to the synthesis of a water-soluble anthraquinone-fluorofuroxan all-in-one molecule, which demonstrated promising NO-releasing ability using 400-500 nm irradiation. A high level of control is displayed with "on" and "off" NO-release functionality suggesting that photosensitizer-furoxan hybrids would make valuable donors. Furthermore, unlike most furoxans, NO is released in the absence of thiol cofactor.
Ruthenium(II)-Catalyzed Double Annulation of Quinones: Step-Economical Access to Valuable Bioactive Compounds
da Silva Júnior, Eufranio N.,de Carvalho, Renato L.,Almeida, Renata G.,Rosa, Luisa G.,Fantuzzi, Felipe,Rogge, Torben,Costa, Pedro M. S.,Pessoa, Claudia,Jacob, Claus,Ackermann, Lutz
supporting information, p. 10981 - 10986 (2020/07/13)
Double ruthenium(II)-catalyzed alkyne annulations of quinones were accomplished. Thus, a strategy is reported that provides step-economical access to valuable quinones with a wide range of applications. C?H/N?H activations for alkyne annulations of naphthoquinones provided challenging polycyclic quinoidal compounds by forming four new bonds in one step. The singular power of the thus-obtained compounds was reflected by their antileukemic activity.
Organocatalytic double arylation of 3-isothiocyanato oxindoles: Stereocontrolled synthesis of complex spirooxindoles
Zhang, Lin-Lin,Da, Bing-Chao,Xiang, Shao-Hua,Zhu, Shuai,Yuan, Zi-Yun,Guo, Zhen,Tan, Bin
supporting information, p. 1689 - 1696 (2018/11/25)
Quinones, precursors of aromatic structures, were firstly employed as the electrophiles for the organocatalytic Michael addition/cyclization cascade reaction with versatile 3-isothiocyanato oxindoles. Chiral bifunctional organocatalyst was appropriate for this enantioselective transformation to afford a variety of novel spirooxindoles, possessing a spirocyclic stereocenter adjacent to the aromatic ring, via asymmetric double arylation. These synthesized spirooxindoles are very difficult to access by the reported methods and were obtained in excellent chemical yields with excellent enantioselectivities.
Generation of Endocyclic Vinyl Carbene Complexes via Gold-Catalyzed Oxidative Cyclization of Terminal Diynes: Toward Naphthoquinones and Carbazolequinones
Shu, Chao,Shi, Chong-Yang,Sun, Qing,Zhou, Bo,Li, Tian-You,He, Qiao,Lu, Xin,Liu, Rai-Shung,Ye, Long-Wu
, p. 1019 - 1025 (2019/01/15)
Carbene cascade reactions involving carbene/alkyne metathesis have attracted much attention over the past decades because this chemistry offers great potential to build complicated cyclic molecules. However, the formed vinyl metal carbenoids in these reactions are limited to exocyclic carbenes, and the generation of endocyclic vinyl carbene complexes remains unexplored. Here, we report an unprecedented gold-catalyzed oxidative cyclization of terminal diynes. Importantly, the generation of endocyclic vinyl carbene complexes was involved in this oxidative cyclization, which is distinctively different from previous protocols. This method allows the facile synthesis of various valuable naphthoquinones and carbazolequinones from readily available diynes under exceptionally mild reaction conditions and features a broad substrate scope and wide functional group tolerance. Moreover, theoretical calculations provide further evidence on the divergent selectivity of this cyclization reaction.
Ruthenium-catalyzed C-H oxygenation of quinones by weak O-coordination for potent trypanocidal agents
Dias, Gleiston G.,Rogge, Torben,Kuniyil, Rositha,Jacob, Claus,Menna-Barreto, Rubem F. S.,Da Silva Júnior, Eufranio N.,Ackermann, Lutz
supporting information, p. 12840 - 12843 (2018/11/30)
Ruthenium-catalysis enabled the C-5 selective C-H oxygenation of naphthoquinones, and also sets the stage for the site-selective introduction of a hydroxyl group into anthraquinones. A-ring modified naphthoquinoidal compounds represent an important class of bioactive quinones for which the present study encompasses the first C-H oxygenation strategy by weak O-coordination.
Ru-Catalyzed Asymmetric Hydrogenative/Transfer Hydrogenative Desymmetrization of Meso-Epoxy Diketones
Hong, Yuping,Chen, Jianzhong,Zhang, Zhenfeng,Liu, Yangang,Zhang, Wanbin
supporting information, p. 2640 - 2643 (2016/06/15)
Via a strategy of asymmetric reductive desymmetrization, chiral cis-epoxy naphthoquinols with multiple contiguous stereocenters and functional groups were synthesized with excellent enantioselectivities (96-99% ee) and diastereoselectivities (8/1-15/1). A combined asymmetric hydrogenation/transfer hydrogenation mechanism was proposed based on experimental results.
Selective iron-catalyzed oxidation of phenols and arenes with hydrogen peroxide: Synthesis of vitamin e intermediates and vitamin k3
Moeller, Konstanze,Wienhoefer, Gerrit,Schroeder, Kristin,Join, Benoit,Junge, Kathrin,Beller, Matthias
experimental part, p. 10300 - 10303 (2010/10/21)
(Figure Presented). Pumping iron! Convenient iron-based catalyst systems for the selective oxidation of arenes and phenols with hydrogen peroxide to give 1, 4-quinones have been developed. This selective oxidation reaction takes place under mild conditions (room temperature, alcoholic solvents) with H 2O2 as the terminal oxidant.
Brominated thiophenes as precursors in the preparation of brominated and arylated anthraquinones
Thiemann, Thies,Tanaka, Yasuko,Iniesta, Jesus
experimental part, p. 1013 - 1031 (2009/10/10)
Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended π-systems with interspersed anthraquinone units.
