261-31-4Relevant academic research and scientific papers
Synthesis of oxidized thioxanthene-type base amplifiers and their application to photoreactive materials
Arimitsu, Koji,Kitamura, Hiroshi,Mizuochi, Ryuta,Furutani, Masahiro
, p. 309 - 311 (2015)
We propose base amplifiers (BAs) that are autocatalytically decomposed into base molecules by a small amount of trigger base molecules from photobase generators. We report here novel BAs having oxidized thioxanthene skeletons. It is confirmed that they are decomposed autocatalytically in solution or polymer matrix. They are applied to UV curing systems to improve their photosensitivity.
Generation and direct observation of the thioxanthenyl and N-methyl acridinyl anions; A family of stable, paratropic, "4N" π-excessives
Anastassiou,Kasmai,Saadein
, p. 3743 - 3746 (1980)
The title, thermally stable, heterocarbanions (2a, 2b) were generated upon respective exposure of conjugate acids 4(a,b) to a KNH2/liq. NH3 system and were shown (NMR) to possess (2a more than 2b) distinct elements of paratropicity.
High-Fidelity Dimerization of Xanthenyl Radicals and Dynamic Qualities of a Congested Ethane: Diethyl Dixanthenyl-9,9′-Dicarboxylate
Dubrawski, Zachary,Gelfand, Benjamin S.,Hogan, David T.,Sutherland, Todd C.
supporting information, (2021/12/23)
Exploration of the sterically-congested ethane diethyl dixanthenyl-9,9′-dicarboxylate has revealed the dynamic behavior arising from its congested C?C bond. Interlocking ‘geared’ substituents and favorable dispersion interactions around this bond result in a conformational preference for partially cofacial xanthene moieties both in solid state and as dilute solutions. The weak, centrally located C?C bond is 1.628 ? long and permits selective thermolysis to yield two carbon-centered ethyl xanthenyl-9-carboxylate radicals, which dimerize with high fidelity into the original sterically-congested ethane. Recombination of the radicals into this symmetrical head-to-head dimer is highly reproducible – by observing the equilibrium, the bond dissociation enthalpy was calculated to be 20.4 kcal ? mol?1. The substituents around the central carbon provide insufficient stabilization against oxygen, which consumes the radicals and unbalances the dimer-radical equilibrium.
Method for reducing carbonyl reduction to methylene under illumination
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Paragraph 0033-0038; 0140-0144, (2021/09/29)
The invention belongs to the technical field of organic chemical synthesis. The method comprises the following steps: (1) mixing the carbonyl compound and the amine compound in a solvent, reacting 3 - 6 under the illumination of 380 - 456 nm, the reaction system is low in toxicity, high in atom utilization rate 12 - 24h. and production efficiency, safe and controllable in reaction process and capable of simplifying the operation in the preparation and production process. At the same time, the residue toxicity of the reaction is minimized, the pollution caused by the production process to the environment is reduced, and the steps and operations of removing residues after the reaction are simplified. In addition, the reactant feedstock is readily available. The reactant does not need additional modification before the reaction, can be directly used for preparing production, simplifies the operation steps, and shortens the reaction route. The production cost is obviously reduced.
Formation and Disproportionation of Xanthenols to Xanthenes and Xanthones and Their Use in Synthesis
Shi, Zeyu,Chen, Si,Xiao, Qiong,Yin, Dali
, p. 3334 - 3343 (2021/02/05)
A facile and versatile strategy employing TiCl4-mediated cyclization followed by a Cannizzaro reaction has been developed for the synthesis of various xanthene derivatives. The reaction proceeded smoothly to afford both xanthenes/xanthones or their sulfur derivatives and tolerated a wide range of electronically diverse substrates. Using this methodology, pranoprofen was synthesized in three steps in 59% overall yield from commercially available starting materials.
Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
supporting information, p. 7315 - 7320 (2020/10/02)
An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
Uncatalyzed Oxidative C?H Amination of 9,10-Dihydro-9-Heteroanthracenes: A Mechanistic Study
van Leest, Nicolaas P.,Grooten, Lars,van der Vlugt, Jarl Ivar,de Bruin, Bas
supporting information, p. 5987 - 5993 (2019/04/03)
A new method for the one-step C?H amination of xanthene and thioxanthene with sulfonamides is reported, without the need for any metal catalyst. A benzoquinone was employed as a hydride (or two-electron and one-proton) acceptor. Moreover, a previously unknown and uncatalyzed reaction between iminoiodanes and xanthene, thioxanthene and dihydroacridines (9,10-dihydro-9-heteroanthracenes or dihydroheteroanthracenes) is disclosed. The reactions proceed through hydride transfer from the heteroarene substrate to the iminoiodane or benzoquinone, followed by conjugate addition of the sulfonamide to the oxidized heteroaromatic compounds. These findings may have important mechanistic implications for metal-catalyzed C?H amination processes involving nitrene transfer from iminoiodanes to dihydroheteroanthracenes. Due to the weak C?H bond, xanthene is an often-employed substrate in mechanistic studies of C?H amination reactions, which are generally proposed to proceed via metal-catalyzed nitrene insertion, especially for reactions involving nitrene or imido complexes that are less reactive (i.e., less strongly oxidizing). However, these substrates clearly undergo non-catalyzed (proton-coupled) redox coupling with amines, thus providing alternative pathways to the widely assumed metal-catalyzed pathways.
Visible-light induced enhancement in the multi-catalytic activity of sulfated carbon dots for aerobic carbon-carbon bond formation
Sarma, Daisy,Majumdar, Biju,Sarma, Tridib K.
supporting information, p. 6717 - 6726 (2019/12/26)
The development of carbonaceous materials as metal-free catalysts integrating different types of catalysis in a single system represents a significant advance in cascade/tandem organic synthesis. Zero-dimensional carbon dots with tuneable optical properties and easily modifiable surface functionalities can be harnessed as a carbocatalyst for merging photooxidation and acid-catalyzed reactions in one pot. Herein, we explore carbon dots decorated with hydrogen sulfate groups as a photocatalyst for the dehydrogenative cross-coupling of xanthenes with ketones, arenes and 1,3-dicarbonyl compounds that showed high efficiency and selectivity under visible-light irradiation. The sulphated carbon dots demonstrate dual catalytic properties, wherein they induced the rapid photooxidation of xanthenes in the presence of molecular oxygen to form a hydroperoxy intermediate followed by coupling of nucleophiles catalysed by the acidic surface functional groups. The methodology represents an operationally simple pathway for the generation of C-C coupling products in a short reaction time with wide substrate scopes under mild conditions. The catalyst is easily separable and can be reused over multiple cycles with good efficiency.
Electrochemical Hydrogenation with Gaseous Ammonia
Li, Jin,He, Lingfeng,Liu, Xu,Cheng, Xu,Li, Guigen
supporting information, p. 1759 - 1763 (2019/01/16)
As a carbon-free and sustainable fuel, ammonia serves as high-energy-density hydrogen-storage material. It is important to develop new reactions able to utilize ammonia as a hydrogen source directly. Herein, we report an electrochemical hydrogenation of alkenes, alkynes, and ketones using ammonia as the hydrogen source and carbon electrodes. A variety of heterocycles and functional groups, including for example sulfide, benzyl, benzyl carbamate, and allyl carbamate were well tolerated. Fast stepwise electron transfer and proton transfer processes were proposed to account for the transformation.
Cu(ii)-catalyzed sulfide construction: both aryl groups utilization of intermolecular and intramolecular diaryliodonium salt
Wang, Ming,Wei, Jianpeng,Fan, Qiaoling,Jiang, Xuefeng
supporting information, p. 2918 - 2921 (2017/03/15)
A sulfur-iodine exchange protocol of diaryliodonium salts with inorganic sulfur salt was developed. Both aryl groups in the diaryliodonium salt were fully exerted in this transformation. Five- to eight-membered sulfur-containing heterocycles were achieved. Note that [1]benzothieno-[3,2-b][1]benzothiophene (BTBT) (an organic field-effect transistor (OFET) material) and Zaltoprofen were efficiently established through this method.
