57483-19-9Relevant academic research and scientific papers
Radical Chain Breaking Bis(ortho-organoselenium) Substituted Phenolic Antioxidants
Upadhyay, Aditya,Singh Bhakuni, Bhagat,Meena, Rahul,Kumar, Sangit
, p. 966 - 973 (2021)
The presence of a chalcogen atom at the ortho-position of phenols enhances their radical chain-breaking activity. Here, a copper(I)-catalyzed reaction of 2,6-dibromo- and 2,6-diiodophenols with diorganodiselenides has been studied for the introduction of two organoselenium substituents at both ortho-positions of the phenolic radical chain-breaking antioxidants, which afforded 2,6-diorganoseleno-substituted phenols in 80–92% yields having electron-donating CH3, and electron-withdrawing CN and CHO functionalities. Additionally, 2,6-diiodophenols with electron-withdrawing CHO and CN groups also afforded novel 5,5′-selenobis(4-hydroxy-3-(phenylselanyl)benzaldehyde) and 5,5′-selenobis(4-hydroxy-3-(phenylselanyl)benzonitrile) consisting of three selenium and two phenolic moieties along with 2,6-diorganoseleno-substituted phenols has been synthesized. The electron-withdrawing CHO group has been reduced by sodium borohydride to the electron-donating alcohol CH2OH group, which is desirable for efficient radical quenching activity of phenols. The developed copper-catalyzed reaction conditions enable the installation of two-arylselenium group ortho to phenolic radical chain-breaking antioxidants, which may not be possible by conventional organolithium-bromine exchange methods due to the sluggish reactivity of trianions (dicarba and phenoxide anion), which are generated by the reaction of organolithium with 2,6-dibromophenols, with diorganodiselenides. The antioxidant activities of the synthesized bis and tris selenophenols have been accessed by DPPH, thiol peroxides, and singlet oxygen quenching assay. The radical quenching antioxidant activity has been studied for the synthesized compounds by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The bis-selenophenols show comparable radical deactivating activity, while tris seleno-bisphenols show higher radical deactivating activity than α-tocopherol. Furthermore, the tris seleno-bisphenol shows comparable peroxide decomposing activity with ebselen molecules.
Metal-Free Synthesis of Phenol-Aryl Selenides via Dehydrogenative C-Se Coupling of Aryl Selenoxides with Phenols
Liu, Zhengfen,Jiang, Yonggang,Liu, Chunxiang,Zhang, Linlin,Wang, Jing,Li, Tiantian,Zhang, Hongbin,Li, Minyan,Yang, Xiaodong
, p. 7386 - 7398 (2020/08/21)
Herein, we disclose the synthesis of diaryl selenides through an unexpected C-Se coupling between aryl benzyl selenoxides and phenols. The synthetic significance of the method is that it provides a mild, rapid, and metal-free access to organoselenides in high yields with excellent functional group tolerance. This coupling of aryl benzyl selenoxides reveals a completely new reaction possibility compared with aryl sulfoxides. We also probed the reaction mechanism of this unexpected transformation through experimental studies and revealed a special Se(IV)-Se(III)-Se(II) reaction pathway.
Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
Xiong, Xiaodong,Yeung, Ying-Yeung
, p. 4033 - 4043 (2018/05/22)
An ortho-selective ammonium chloride salt-catalyzed direct C-H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated BINOLs are useful synthons for the synthesis of a wide range of unsymmetrical 3-aryl BINOLs that are not easily accessible. In addition, the same catalytic system can facilitate the ortho-selective selenylation of phenols.
C-Se cross-coupling of arylboronic acids and diphenyldiselenides over non precious transition metal (Fe, Cu and Ni) complexes
Sahani, Amber J.,Jayaram, Radha V.,Burange, Anand S.
, p. 14 - 18 (2018/04/26)
Various tetradentate and tridentate ligands such as salophane, bishydrazone, bisbenzimidazolyl pyridine and isonicotinohydrazide have been prepared. Transition metal complexes of these ligands with Cu, Ni and Fe have been further synthesized and characterized by UV–vis, IR, NMR and CHN analysis. Catalytic activity of the metal complexes was tested for the cross coupling of diarylchalcogenide with arylboronic acid in DMSO as solvent in presence of a base. These non-precious metal complexes catalysed cross coupling reactions smoothly in shorter reaction time compared to earlier reports with comparable yields.
Transition-metal-free synthesis of unsymmetrical diaryl chalcogenides from arenes and diaryl dichalcogenides
Prasad, Ch Durga,Balkrishna, Shah Jaimin,Kumar, Amit,Bhakuni, Bhagat Singh,Shrimali, Kaustubh,Biswas, Soumava,Kumar, Sangit
, p. 1434 - 1443 (2013/03/29)
A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by 77Se NMR spectroscopy by using diphenyl diselenide as the substrate. 77Se NMR study suggests that electrophilic species ArE+ is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
A general and green procedure for the synthesis of organochalcogenides by CuFe2O4 nanoparticle catalysed coupling of organoboronic acids and dichalcogenides in PEG-400
Kundu, Debasish,Mukherjee, Nirmalya,Ranu, Brindaban C.
, p. 117 - 125 (2013/04/10)
A general and efficient procedure has been developed for the synthesis of organochalcogenides (selenides and tellurides) by a simple reaction of organoboronic acids and dichalcogenides catalysed by CuFe2O 4 nanoparticles in PEG-400 without any ligand. This protocol offers the scope for access to a wide spectrum of chalcogenides including diaryl, aryl-heteroaryl, aryl-styrenyl, aryl-alkenyl, aryl-allyl, aryl-alkyl and aryl-alkynyl versions. The catalyst is magnetically separable and recyclable eight times without any loss of appreciable catalytic activity. The products are obtained in high purities after evaporation of solvent followed by filtration column chromatography. The Royal Society of Chemistry.
Iodine-catalyzed selective synthesis of 2-sulfanylphenols via oxidative aromatization of cyclohexanones and disulfides
Ge, Wenlei,Zhu, Xun,Wei, Yunyang
supporting information, p. 3014 - 3021 (2014/03/21)
Iodine-catalyzed intermolecular dehydrogenative aromatizations of six-membered cyclohexanones for the selective synthesis of 2-sulfanylphenols have been developed. Both aryl and alkyl disulfides can be used as sulfanylation reagents to give the desired pr
Relations between 77Se NMR chemical shifts of (phenylseleno)-benzenes and their molecular structures derived from nine X-ray crystal structures
Oddershede, Jette,Henriksen, Lars,Larsen, Sine
, p. 1053 - 1060 (2007/10/03)
An extensive library of 77Se chemical shifts have been generated from the NMR measurements on substituted (phenylseleno)benzenes, including 33 new compounds. The variation in chemical shifts cover 265 ppm ranging from 446 to 181 ppm. Crystal st
Competing ene-reactions in the p-oxidation and o-phenylselenylation of phenol with benzeneseleninic acid
Henriksen, Lars
, p. 7057 - 7060 (2007/10/02)
Reaction of phenol with benzeneseleninic acid gives 2-(phenylseleno)- and 2,6-bis(phenylseleno)-1,4-benzoquinone via the corresponding 2- and 2,6-selenylated phenols; initiating ene-reactions are suggested for both the o-selenylation and the p-oxidation sequence.
Direct Selenation of Electron-Rich Aromatic Compounds with (Phenylseleno)dimethylsulfonium Tetrafluoroborate
Gassman, Paul G.,Miura, Asako,Miura, Takashi
, p. 951 - 954 (2007/10/02)
(Phenylseleno)dimethylsulfonium tetrafluoroborate was found to be a highly reactive selenating agent for electron-rich aromatic compounds such as aromatic amines, phenols, and aromatic ethers.Reaction took place readily at 0-25 deg C to give ca. 50percent yields of substitution para to the activating substituent.In general, anilines gave better yields then anisoles or phenols.
