20461-30-7Relevant articles and documents
SYN REGIOSELECTIVITY OF THE HYDROPEROXIDATION OF CYCLO-ALKENES WITH SINGLET OXYGEN
Jefford, Charles W.,Rimbault, Christian G.
, p. 91 - 94 (1981)
The regioselectivity of hydroperoxidation of 1-alkylcycloalkenes is rationalized in terms of the formation of a zwitterionic peroxide.
Oxygen Quenching of Electronically Excited Hexanuclear Molybdenum and Tungsten Halide Clusters
Jackson, Julie A.,Turro, Claudia,Newsham, Mark D.,Nocera, Daniel G.
, p. 4500 - 4507 (1990)
Quenching of the electronically excited Y6(2-) (M = Mo(II), W(II), X,Y = Cl,Br,I) ions by molecular oxygen has been investigated.Stern- Volmer analysis of emission intensity and lifetime data reveals that the rate constants for oxygen quenching of the Y6(2-) ions are similar (kqobs = 8.1(37) * 1E7 M-1 s-1) with the exception of the Y6(2-) clusters, which exhibit significantly greater quenching rates (kqobs = 2.1(5) * 1E9 M-1 s-1).Photosensitized oxidation of 1-methylcyclohexene and 1,2-dimethylcyclohexene by all Y6(2-) clusters yields products expected for the reaction of the olefins with singlet oxygen.No evidence of radical autooxidation products were detected.However, the measured quantum yields for the photooxidation of 2,3-diphenyl-p-dioxene by only the Y6(2-) (M = no W; X = no I) clusters are in agreement with the values calculated from a kinetic scheme involving the exclusive production of singlet oxygen by direct energy transfer; observed quantum yields of Y6(2-) -photosensitized reactions are not consistent with this scheme.One explanation for the enhanced oxygen quenching rates of the Y6(2-) excited states (Y6(2-)(excit)) and anomalous observed quantum yields is the contribution of an electron-transfer pathway to the quenching reaction.Transient absorption spectra for the reaction between W6I14(2-)(excit.) and oxygen, however, do not display transients attributable to electron-transfer products.Accordingly, we ascribe the enhanced quenching rate of Y6(2-)(excit.) by oxygen to greater adiabaticity of the energy-transfer reactions of these ions as compared to their homologous cluster counterparts.The absence of an electron-transfer contribution to the Y6(2-)-cluster photosensitized production of 1O2 (Y6(2-)(excit.) + O2 -> Y6(1-) + O2(1-) -> Y6(2-) + 1O2) parallels the results observed for the photosensitized production of 1O2 by RuL3(2+) (L = plypyridyl) systems, which also produce singlet oxygen exclusively by energy transfer despite the existence of potential electron-transfer pathway.
CHOLINE METABOLISM INHIBITORS
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Page/Page column 50; 104, (2020/07/05)
The present disclosure relates to compounds, compositions and methods for inhibiting choline metabolism, e.g., conversion of choline to trimethylamine. Disclosed herein are compounds, compositions, and methods for inhibiting choline metabolism, e.g., conversion of choline to TMA. Also disclosed herein are compounds, methods and compositions for inhibiting choline metabolism by gut microbiota resulting in reduction in the formation of trimethylamine (TMA) and trimethylamine N-oxide (TMAO).
Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols
Ye, Ke-Yin,Mccallum, Terry,Lin, Song
supporting information, (2019/06/24)
Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton transfer/electron transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.
