10075-62-4Relevant articles and documents
Photooxygenation of oxygen-substituted naphthalenes
Bauch, Marcel,Krtitschka, Angela,Linker, Torsten
, (2017)
The reaction of oxygen-substituted naphthalenes with singlet oxygen (1O2) has been investigated, and labile endoperoxides have been isolated and characterized at –78°C for the first time. Low-temperature kinetics by UV spectroscopy revealed that alkoxy and silyloxy substituents remarkably increase the rate of photooxygenations compared to 1,4-dimethylnaphthalene, whereas acyloxy-substituted acenes are inert towards 1O2. The reactivities nicely correlate with HOMO energies and free activation energies, which we determined by density functional theory calculations. The lability of the isolated endoperoxides is due to their very fast back reaction to the corresponding naphthalenes even at –20°C under release of 1O2, making them to superior sources of this reactive species under very mild conditions. Finally, a carbohydrate-substituted naphthalene has been synthesized, which reacts reversibly with 1O2 and might be applied for enantioselective oxidations in future work.
Studies on synthesis of quinonylidene Hoveyda-type complexes
Grudzień, Krzysztof,Barbasiewicz, Micha?
, p. 322 - 327 (2015)
In a quest of redox-switchable metathesis catalysts we attempted synthesis of ruthenium quinonylidene complexes using two synthetic pathways. First, Hoveyda-type complexes bearing chelating benzylidene and naphthylidene ligands substituted with two alkoxy/hydroxy groups were synthesized and characterized. The catalysts were tested in model ring-closing metathesis reactions, and displayed interesting correlations between structure and catalytic activity. Unfortunately, numerous attempts at oxidation of the complexes to derivatives of benzo- and naphthoquinone were unsuccessful. However, the second approach, using exchange reaction of ruthenium precursor with vinylquinone ligand, gave a transient unstable product observed with 1H NMR. The experimental data suggest that conjugation of electron-deficient quinones to the ruthenium centre results in intrinsically unstable species, which undergo secondary reactions under ambient conditions.
Baker's Yeast Mediated Reduction of Aromatic Ring Substituted 2-Tetralones
Manitto, Paolo,Speranza, Giovanna,Monti, Diego,Fontana, Gabriele,Panosetti, Elisa
, p. 11531 - 11546 (1995)
2-Tetralones mono- and disubstituted with methoxy or hydroxy groups in the aromatic ring are hydrogenated to 2-tetralols in good yields by non-fermenting baker's yeast.The prevalent enantioform of the reduction product and its e.e. were found to depend on the substitution pattern.In one case, i.e. the biotransformation of 5-methoxy-2-tetralone into the corresponding 2-tetralol, an e.e. >/= 98percent was observed.A simple abstract model for explaining and predicting the stereochemical outcome in the yeast-mediated carbonyl reduction of 2-tetralones is proposed.
Photoelectrocyclization Reactions of Amidonaphthoquinones
Landward, Michael B.,Rainier, Jon D.,Yin, Jinya
, p. 4298 - 4311 (2020/04/10)
Readily available acrylamide naphthoquinones can be converted into the corresponding aza-anthraquinones using 6?-photoelectrocyclization reactions. Not only do these reactions not proceed thermally but, as demonstrated here, they can also be used to generate a range of aza-anthraquinone and aza-tetracycline derivatives including the natural products griffithazanone A and marcanine A. Several of the aza-anthraquinones generated in this work showed antibacterial activity.
Direct Synthesis of Hydroquinones from Quinones through Sequential and Continuous-Flow Hydrogenation-Derivatization Using Heterogeneous Au–Pt Nanoparticles as Catalysts
Miyamura, Hiroyuki,Tobita, Fumiya,Suzuki, Aya,Kobayashi, Shū
supporting information, p. 9220 - 9224 (2019/06/13)
Pt–Au bimetallic nanoparticle catalysts immobilized on dimethyl polysilane (Pt–Au/(DMPSi-Al2O3)) have been developed for selective hydrogenation of quinones to hydroquinones. High reactivity, selectivity, and robustness of the catalysts were confirmed under continuous-flow conditions. Various direct derivatizations of quinones, such as methylation, acetylation, trifluoromethanesulfonylation, methacrylation, and benzoylation were successfully performed under sequential and continuous-flow conditions to afford the desired products in good to excellent yields. Especially, air-sensitive hydroquinones, such as anthrahydroquinones and naphthohydroquinones, could be successfully generated and derivatized under closed sequential and continuous-flow conditions without decomposition.
