134-81-6Relevant articles and documents
Molecular iodine/DMSO mediated oxidation of internal alkynes and primary alcohols using a one-pot, two step approach towards 2,4,5-trisubstituted imidazoles: Substrate scope and mechanistic studies
Jeena, Vineet,Naidoo, Shivani
, (2020)
An efficient, eco-friendly and practical oxidation of internal alkynes and primary alcohols as key steps towards the synthesis of 2,4,5-trisubstituted imidazoles is reported. This green synthetic methodology employed an acid and metal-free molecular iodine/DMSO system, to afford a variety of substituted imidazoles in moderate to good yields, with a range of functionalities tolerated. Mechanistic studies revealed two distinct oxidation pathways, which ultimately form the diketone and aldehyde that serve as key intermediates in the multicomponent domino synthesis.
Reductive homo-coupling of 2-aryl-2-oxazolinium salts
Shono,Kise,Nomura,Yamanami
, p. 3577 - 3580 (1993)
The reductive homo-coupling of 2-aryl-2-oxazolinium salts was achieved by reduction with Zn-CTMS, electroreduction with zinc anode, or direct electroreduction. The homo-coupled products were converted to α-diketones.
Synthesis of a new class of cationic Pd(II) complexes with 1,2,3-triazol-5-ylidene ligand and their catalytic application in the conversion of internal alkynes to 1,2-diketones
Shaik, Jeelani Basha,Ramkumar, Venkatachalam,Sankararaman, Sethuraman
, p. 1 - 8 (2018)
A new class of cationic Pd(II) complexes of the type [Pd(Tz)(Cl)(bipy)]+Cl? and [Pd (Tz)(Cl)(phen)]+Cl? (Tz = 1,4-diaryl-3-methyl-1,2,3-triazol-5-ylidene, bipy = 2,2′-bipyridine and phen = 1,10-phenanthroline) with various wing tip groups were synthesized from the corresponding 1,2,3-triazolium iodide via the corresponding chloro bridged dinuclear complexes [(Tz)(Cl)Pd(μ-Cl)2Pd(Cl)(Tz)]. The synthesized cationic complexes were screened for their catalytic activity of hydration of alkynes and found to be excellent towards the selective conversion of internal alkynes to the corresponding 1,2-diketones in good yields. A plausible mechanism was proposed for this conversion.
A Time-resolved EPR Study of One- and Two-Photon Processes in the Photochemical Reactions of Benzil
Mukai, Masahiro,Yamauchi, Seigo,Hirota, Noboru
, p. 4411 - 4413 (1989)
A time-resolved EPR study of the photochemical reactions of benzil in isopropyl alcohol and a benzene-triethylamine (TEA) mixed solvent is reported.Emissive and absorptive chemically induced dynamic electron polarization signals of the intermediate radicals were observed in these two systems.The observed radicals are assigned as the benzoyl and benzil ketyl radicals in the former case and the benzil anion in the latter case.It is found that these photochemical reactions occur from the higher excited triplet state through a two-photon process in isopropyl alcohol and from the lowest excited triplet state through a one-photon process in the benzene-TEA mixed solvent, respectively.
A new hydrazone-based colorimetric chemosensor for naked-eye detection of copper ion in aqueous medium
Shi, Shao-Min,Li, Qiao,Hu, Sheng-Li
, p. 426 - 430 (2019)
A new hydrazone-based colorimetric Cu2+ chemosensor is synthesized. Its structure was confirmed by single-crystal X-ray diffraction. Its binding properties towards various metal ions are examined through absorption spectroscopy. In aqueous THF solution, the chemosensor exhibits selective recognition towards Cu2+ over other metal ions with a colour change from colourless to pink. The complex formed between the chemosensor and Cu2+ ions forms a 2:1 stoichiometry with an association constant of 2.46 × 108M?2. The analytical detection limit for Cu2+ by the naked eye is as low as 10.0 μM.
Formic acid oxidatively cleaves 1,2,3,4-tetraaryl-2-butene-1,4-diones to 1,2-diaryl-1,2-ethanediones under microwave irradiation
Rao, H. Surya Prakash,Jothilingam,Vasantham,Scheeren, Hans W.
, p. 4495 - 4497 (2007)
Formic acid oxidatively cleaves 1,2,3,4-tetraaryl-2-butene-1,4-diones (1,2-aroylstilbenes) to 1,2-diaryl-1,2-ethanediones (benzils) under microwave irradiation. Mechanistic probing revealed that formic acid incorporates one of its oxygen atoms into benzil.
Gold-Catalyzed Intermolecular Alkyne Oxyarylation for C3 Functionalization of Benzothiophenes
Rist, Paige A.,Grainger, Richard S.,Davies, Paul W.
, p. 642 - 646 (2021)
C3-selective C-C bond formation on benzothiophenes is challenging, and few direct functionalization methods are available. A gold-catalyzed reaction of alkynes with benzothiophene S-oxides provides regioselective entry into C3-alkylated benzothiophenes with the C7-alkylated isomer as the minor product. This oxyarylation reaction works with alkyl and aryl alkynes and substituted and unsubstituted benzothiophenes. Mechanistic studies identify that sulfoxide inhibits the catalyst [DTBPAu(PhCN)]SbF6, which also degrades and forms the unreactive complex [(DTBP)2Au]SbF6.
Oxidation of Organic Molecules with a Redox-Active Guanidine Catalyst
Wild, Ute,Sch?n, Florian,Himmel, Hans-J?rg
, p. 16410 - 16413 (2017)
Herein, we report the first examples of the use of redox-active guanidines as catalysts in the green oxidation of organic molecules with dioxygen. In one half-reaction, the oxidized form of the redox-active guanidine is converted into the reduced, protonated state, thereby enabling dehydrogenative oxidation of the substrate (3,5-di-tert-butylcatechol→ortho-benzoquinone, benzoin→benzil, and 2,4-di-tert-butylphenol→biphenol). In the other half-reaction, efficient re-oxidation of the guanidine to the oxidized state is achieved with dioxygen in the presence of a copper catalyst. These results pave the way for the broader use of redox-active guanidines as oxidation catalysts.
Cathodic coupling of aliphatic esters. Useful reaction for the synthesis of 1,2-diketone and acyloin
Kashimura, Shigenori
, p. 4805 - 4808 (1995)
It has been found in this study that electroreduction of aliphatic ester (1) with Mg electrode leads to the formation of the corresponding 1,2-diketone under aprotic conditions, whereas bis(trimethylsilyloxy)alkene is afforded through acyloin condensation when the reduction is carried out in the presence of chlorotrimethylsilane.
Recyclable Pd-contained perovskite catalyst synthesized by a low temperature hydrothermal method for aerobic alcohol oxidation
Saputra, Leo,Kojima, Takashi,Hara, Takayoshi,Ichikuni, Nobuyuki,Shimazu, Shogo
, p. 132 - 138 (2018)
We successfully prepared Pd-containing perovskite strontium titanate (Pd-STO) by a relatively low-temperature hydrothermal method (i.e., 373 K) without posterior calcination. The particle size and porosity of the STO perovskite could be tuned by changing the molar ratio of H2O/NH3 (e.g., 5.0, 12.5 and 25.0) during the preparation of the amorphous titania sources. The mesoporous contained Pd-STO(12.5) showed superior catalytic performance compared to that of the other Pd-STO(x) (x = H2O/NH3) perovskites for alcohol oxidation with molecular oxygen. Both the refluxing of the non-polar solvents and addition of molecular sieves enhanced the reaction yield significantly. The Pd-incorporated perovskite (Pd-STO) showed better recyclability compared with that of the impregnated perovskite (imp-Pd/STO).
