2709-93-5Relevant articles and documents
Site-Selective C?H Oxygenation via Aryl Sulfonium Salts
Sang, Ruocheng,Korkis, Stamatis E.,Su, Wanqi,Ye, Fei,Engl, Pascal S.,Berger, Florian,Ritter, Tobias
supporting information, p. 16161 - 16166 (2019/11/03)
Herein, we report a two-step process forming arene C?O bonds in excellent site-selectivity at a late-stage. The C?O bond formation is achieved by selective introduction of a thianthrenium group, which is then converted into C?O bonds using photoredox chemistry. Electron-rich, -poor and -neutral arenes as well as complex drug-like small molecules are successfully transformed into both phenols and various ethers. The sequence differs conceptually from all previous arene oxygenation reactions in that oxygen functionality can be incorporated into complex small molecules at a late stage site-selectively, which has not been shown via aryl halides.
New insight on the mechanism of the catalytic hydrogenation of nitrobenzene to 4-aminophenol in CH3CN-H2O-CF3COOH as a reusable solvent system.
Quartarone, Giuseppe,Ronchin, Lucio,Tosetto, Alice,Vavasori, Andrea
, p. 169 - 178 (2014/03/21)
The preparation of 4-aminophenol via hydrogenation of nitrobenzene in a single liquid phase has been carried in the presence of different precious metal catalysts. The liquid phase is composed of CH3CN-H 2O-CF3COOH, which can be easily distilled at low temperature, thus avoiding work-up operation. The yield of 4-aminophenol is in the range 45% and in the presence of sulfolane as promoter reaches almost 50%. The best result has been obtained in the presence of Pt/C as hydrogenation catalyst. The role of the solvent is strictly related to the selectivity to 4-aminophenol, since CH3CN decreases the hydrogenation activity compared to other solvent, CF3COOH promotes the formation of the desired product both via Bamberger rearrangement in solution as well by a surface catalyzed reaction, while H2O is responsible for 4-aminophenol formation in both reactions. Even though, nitrosobenzene and phenylhydroxylamine have not been observed, their reactivity suggest a complex pattern of reactions occurring either on the catalyst surface or in the solution. Indeed, formation of 4-aminophenol may occur both in solution, via acid catalyzed Bamberger rearrangement and on the catalyst surface by the formation of a surface Pt-nitrenium complex, which undergoes surface nucleophilic attack by H2O.
A thermally reversible temperature sensor based on polydiacetylene: Synthesis and thermochromic properties
Chen, Xiaoqiang,Yoon, Juyoung
experimental part, p. 194 - 198 (2011/09/20)
A novel temperature sensor based on polydiacetylene, displayed colorimetrically reversible properties in the range of 30 °C and 70 °C in solution. PVA film embedded PDA supramolecules displayed similar temperature reversibility.
