96517-08-7Relevant articles and documents
Molybdenum-doped α-MnO2 as an efficient reusable heterogeneous catalyst for aerobic sulfide oxygenation
Uematsu, Tsubasa,Miyamoto, Yumi,Ogasawara, Yoshiyuki,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 222 - 233 (2015/12/31)
Oxygenation of sulfides to sulfoxides and/or sulfones is an important transformation, and the development of efficient heterogeneous catalysts for oxygenation, which can utilize O2 as the terminal oxidant, is highly desired. In this study, we have successfully developed manganese oxide-based efficient heterogeneous catalysts for aerobic oxygenation of sulfides. Firstly, we prepared four kinds of manganese oxides possessing different crystal structures, such as α-MnO2, β-MnO2, γ-MnO2, and δ-MnO2, and their structure-activity relationships were examined for the aerobic oxygenation of thioanisole. Amongst them, α-MnO2 showed the best catalytic performance for the oxygenation. Moreover, α-MnO2 was highly stable during the catalytic oxygenation possibly due to the tunnel K+ ions. In order to further improve the catalytic performance of α-MnO2, substitutional doping of transition metal cations, such as Mo6+, V5+, Cr3+, and Cu2+, into the framework was carried out. Undoped α-MnO2 possessed a fibrous morphology. When high-valent transition metal cations were doped, especially Mo6+, the lengths of the fibers drastically shortened to form grain-like aggregates of ultrafine nanocrystals, resulting in an increase in specific surface areas and the numbers of catalytically active surface sites. In the presence of Mo6+-doped α-MnO2 (Mo-MnO2), various kinds of sulfides could efficiently be oxidized to the corresponding sulfoxides as the major products. The observed catalysis was truly heterogeneous, and Mo-MnO2 could repeatedly be reused while keeping its high catalytic performance. Besides sulfide oxygenation, Mo-MnO2 could efficiently catalyze several aerobic oxidative functional group transformations through single-electron transfer oxidation processes, namely, oxygenation of alkylarenes, oxidative α-cyanation of trialkylamines, and oxidative S-cyanation of benzenethiols.
Potassium thiocyanate as source of cyanide for the oxidative α-cyanation of tertiary amines
Wagner, Alexander,Ofial, Armin R.
, p. 2848 - 2854 (2015/03/18)
Oxidation at the sulfur of the safe-to-handle potassium thiocyanate releases cyanide units that are trapped in the presence of co-oxidized tertiary amines to form α-amino nitriles. These cyanations work in aqueous solutions and do not require a catalyst,
Visible-light-induced photoredox catalysis with a tetracerium-containing silicotungstate
Suzuki, Kosuke,Tang, Fei,Kikukawa, Yuji,Yamaguchi, Kazuya,Mizuno, Noritaka
supporting information, p. 5356 - 5360 (2014/06/09)
The development of visible-light-induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials for efficient photocatalysts because their properties can be p
Mono-N-alkylation of α-Aminoacetonitriles. A Novel Route to Unsymmetrical Secondary Amines
Katritzky, Alan R.,Latif, Muhammad,Urogdi, Laszlo
, p. 667 - 672 (2007/10/02)
Mannich-type condensation products of an aldehyde with an α-aminoacetonitrile and benzotriazole are treated with sodium borohydride or with a Grignard reagent to give unsymmetrical N,N-dialkylaminoacetonitriles, which, on decyanomethylation provide unsymmetrical secondary amines.
A New Method of α-Functionalization for Tertiary Amines by Nucleophilic Substitution of α-Siloxy Amines
Tokitoh, Norihiro,Okazaki, Renji
, p. 735 - 740 (2007/10/02)
α-Siloxy amines, which were easily prepared by "silicon Polonovski reaction" of tertiary amine N-oxides with trialkylsilyl trifluoromethanesulfonate, were treated with various nucleophiles to give the corresponding α-functionalized tertiary amines in moderate to good yields.This new method has to the advantage that it enables the α-substitution of amines not only by alkyl groups but also by alkenyl and aryl groups with sp2 carbon as a reaction center, since the introduction of such groups is difficult in electrophilic substitution of dipole-stabilized α-lithio amines.Besides the organometallics such as Grignard and organoaluminum reagents, trimethylsilyl cyanide and silyl enol ether could also be employed as nucleophiles in the presence of an appropriate Lewis acid.
A NEW SYNTHESIS OF α-CYANOAMINES. LEWIS ACID PROMOTED NUCLEOPHILIC SUBSTITUTION OF α-SILOXYAMINES USING TRIMETHYLSILYL CYANIDE
Tokitoh, Norihiro,Okazaki, Renji
, p. 241 - 242 (2007/10/02)
α-Siloxyamines obtained from tertiary amines via their N-oxides were treated with titanium tetrachloride and trimethylsilyl cyanide to give α-cyanated tertiary amines in good yields.
