614-13-1Relevant academic research and scientific papers
Cationic [5+2] cycloaddition reactions promoted by trimethylsilyl triflate in highly polar media
Collins, Jon L.,Grieco, Paul A.,Walker, John K.
, p. 1321 - 1324 (1997)
Trimethylsilyl triflate is an effective reagent in 3.0 M lithium perchlorate-ethyl acetate for promoting cationic [5+2] cycloaddition reactions.
Reaction of Alkenes with Unstable Cations Electrogenerated from Phenols
Shizuri, Yoshikazu,Nakamura, Kensuke,Yamamura, Shosuke
, p. 530 - 531 (1985)
Reactions of several alkenes with the unstable cations electrogenerated fron 3,4-dimethoxy-6-methylphenol as well as from p-methoxyphenol have been carried out, resulting in C-C bond formation to give the corresponding 1:1 adducts.
Organophotocatalytic Aerobic Oxygenation of Phenols in a Visible-Light Continuous-Flow Photoreactor
Wellauer, Jo?l,Miladinov, Dragan,Buchholz, Thomas,Schütz, Jan,Stemmler, René T.,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
supporting information, p. 9748 - 9752 (2021/05/27)
A mild photocatalytic phenol oxygenation enabled by a continuous-flow photoreactor using visible light and pressurized air is described herein. Products for wide-ranging applications, including the synthesis of vitamins, were obtained in high yields by precisely controlling principal process parameters. The reactor design permits low organophotocatalyst loadings to generate singlet oxygen. It is anticipated that the efficient aerobic phenol oxygenation to benzoquinones and p-quinols contributes to sustainable synthesis.
Polyoxometalate-based supramolecular porous frameworks with dual-active centers towards highly efficient synthesis of functionalized: P -benzoquinones
An, Haiyan,Chang, Shenzhen,Chen, Yanhong,Huang, Yaohui,Luo, Huiyun,Zhu, Qingshan
, p. 8591 - 8603 (2021/11/17)
Selective oxidation of substituted phenols is an ideal method for preparing functionalized p-benzoquinones (p-BQs), which serve as versatile raw materials for the synthesis of a variety of biologically active compounds. Herein, two new polyoxometalate-based supramolecular porous frameworks, K3(H2O)4[Cu(tza)2(H2O)]2[Cu(Htza)2(H2O)2][BW12O40]·6H2O (1) and H3K3(H2O)3[Cu(Htza)2(H2O)]3[SiW12O44]·14H2O (2) (Htza = tetrazol-1-ylacetic acid), were synthesized and structurally characterized by elemental analysis, infrared spectroscopy, thermal analysis, UV-vis diffuse reflectance spectroscopy, and single-crystal X-ray and powder diffraction. The single-crystal X-ray diffraction analysis indicates that both compounds possess unique petal-like twelve-nucleated Cu-organic units composed of triangular and hexagonal metal-organic loops. In 1, the Cu-organic units are isolated and [BW12O40]5- polyoxoanions are sandwiched between staggered adjacent triangular channels in the structure. However in 2, the Cu-organic units extend into a two-dimensional layered structure, and the [SiW12O44]12- polyoxoanions occupy the larger hexagonal channels in the stacked structure. Both compounds as heterogeneous catalysts can catalyze the selective oxidation of substituted phenols to high value-added p-BQs under mild conditions (60 °C) with TBHP as the oxidant, particularly in the oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-p-benzoquinone (TMBQ, key intermediate in vitamin E production). Within 8-10 min, the yield of TMBQ is close to 100%, and oxidant utilization efficiency is up to 94.2% for 1 and 90.9% for 2. The turnover frequencies of 1 and 2 are as high as 5000 and 4000 h-1, respectively. No obvious decrease in the yield of TMBQ was observed after five cycles, which indicates the excellent sustainability of both compounds. Our study of the catalytic mechanism suggests that there is a two-site synergetic effect: (i) the copper ion acts as the catalytic site of the homolytic radical pathway; and (ii) the polyoxoanion acts as the active center of the heterolytic oxygen atom transfer pathway. This journal is
Oxidation of Electron-Rich Arenes Using HFIP-UHP System
Llopis, Natalia,Baeza, Alejandro
, p. 6159 - 6164 (2020/05/20)
The straightforward oxidation of electron-rich arenes, namely, phenols, naphthols, and anisole derivatives, under mild reaction conditions, is described by means of the use of an environmentally benign HFIP-UHP system. The corresponding quinones or hydroxylated arenes were obtained in moderate to good yields.
Regiodivergent oxidation of alkoxyarenes by hypervalent iodine/oxone system
China, Hideyasu,Tanihara, Kokoro,Sasa, Hirotaka,Kikushima, Kotaro,Dohi, Toshifumi
, p. 2 - 8 (2019/09/10)
We have found that the combination of Oxone with an organoiodine compound, i.e., 2-iodobenzoic acid (2-IB), selectively yields p-quinones from monomethoxyarenes under mild conditions. In this reaction system, an organoiodine compound is immediately oxidized by Oxone to generate cyclic hypervalent iodine (III) species in situ, which serves as the specific mediator for the selective p-quinone synthesis, preventing o-quinone formation.
An expedient synthesis of murrayaquinone A via a novel oxidative free radical reaction
McDonald, Jeffrey W.,Miller, John E.,Kim, Minjee,Velu, Sadanandan E.
, p. 550 - 553 (2018/01/17)
Murrayaquinones A–D is a group of four bioactive carbazole-1,4-dione natural products isolated from the root bark of the plant Murraya eucrestifolia hayata. Murrayaquinone is synthesized in five steps starting from the commercially available 2,4,5-trimeth
A Catalytic Oxidative Quinone Heterofunctionalization Method: Synthesis of Strongylophorine-26
Yu, Wanwan,Hjerrild, Per,Jacobsen, Kristian M.,Tobiesen, Henriette N.,Clemmensen, Line,Poulsen, Thomas B.
supporting information, p. 9805 - 9809 (2018/07/31)
The preparation of heteroatom-substituted p-quinones is ideally performed by direct addition of a nucleophile followed by in situ reoxidation. Albeit an appealing strategy, the reactivity of the p-quinone moiety is not easily tamed and no broadly applicable method for heteroatom functionalization exists. Shown herein is that Co(OAc)2 and Mn(OAc)3?2 H2O act as powerful catalysts for oxidative p-quinone functionalization with a collection of O, N, and S nucleophiles, using oxygen as the terminal oxidant. Preliminary mechanistic observations and the first synthesis of the cytotoxic natural product strongylophorine-26 is presented.
Synthesis of coenzyme Q0 through divanadium-catalyzed oxidation of 3,4,5-trimethoxytoluene with hydrogen peroxide
Zalomaeva, Olga V.,Evtushok, Vasilii Yu.,Maksimov, Gennadii M.,Maksimovskaya, Raisa I.,Kholdeeva, Oxana A.
, p. 5202 - 5209 (2017/04/27)
The selective oxidation of methoxy/methyl-substituted arenes to the corresponding benzoquinones has been first realized using aqueous hydrogen peroxide as a green oxidant, acid tetrabutylammonium salts of the γ-Keggin divanadium-substituted phosphotungstate [γ-PW10O38V2(μ-O)2]5- (I) as a catalyst, and MeCN as a solvent. The presence of the dioxovanadium core in the catalyst is crucial for the catalytic performance. The reaction requires an acid co-catalyst or, alternatively, a highly protonated form of I can be prepared and employed. The industrially relevant oxidation of 3,4,5-trimethoxytoluene gives 2,3-dimethoxy-5-methyl-1,4-benzoquinone (ubiquinone 0 or coenzyme Q0, the key intermediate for coenzyme Q10 and other essential biologically active compounds) with 73% selectivity at 76% arene conversion. The catalyst retains its structure under turnover conditions and can be easily recycled and reused without significant loss of activity and selectivity.
Dimethyl carbonate: an environmentally friendly solvent for hydrogen peroxide (H2O2)/methyltrioxorhenium (CH3ReO3, MTO) catalytic oxidations
Bernini, Roberta,Mincione, Enrico,Barontini, Maurizio,Crisante, Fernanda,Fabrizi, Giancarlo,Gambacorta, Augusto
, p. 6895 - 6900 (2008/02/10)
Environmentally friendly oxidations of various organic compounds with the hydrogen peroxide (H2O2)/methyltrioxorhenium (CH3ReO3, MTO) catalytic system have been described in dimethyl carbonate (DMC), a cheap commercially available and benign chemical having interesting solvating properties, low toxicity and high biodegradability. Oxidations proceeded with good conversions and in good yields. Spectrophotometric analysis demonstrated that the [CH3ReO(O-O)2] complex was formed in DMC and that it was stable for several days at room temperature.
