454-89-7Relevant articles and documents
Enhancement of the Oxidizing Power of an Oxoammonium Salt by Electronic Modification of a Distal Group
Lambert, Kyle M.,Stempel, Zachary D.,Kiendzior, Sadie M.,Bartelson, Ashley L.,Bailey, William F.
, p. 11440 - 11446 (2017)
The multigram preparation and characterization of a novel TEMPO-based oxoammonium salt, 2,2,6,6-tetramethyl-4-(2,2,2-trifluoroacetamido)-1-oxopiperidinium tetrafluoroborate (5), and its corresponding nitroxide (4) are reported. The solubility profile of 5 in solvents commonly used for alcohol oxidations differs substantially from that of Bobbitt's salt, 4-acetamido-2,2,6,6-tetramethyl-1-oxopiperidinium tetrafluoroborate (1). The rates of oxidation of a representative series of primary, secondary, and benzylic alcohols by 1 and 5 in acetonitrile solvent at room temperature have been determined, and oxoammonium salt 5 has been found to oxidize alcohols more rapidly than does 1. The rate of oxidation of meta- and para-substituted benzylic alcohols by either 1 or 5 displays a strong linear correlation to Hammett parameters (r > 0.99) with slopes (ρ) of -2.7 and -2.8, respectively, indicating that the rate-limiting step in the oxidations involves hydride abstraction from the carbinol carbon of the alcohol substrate.
Photooxidation of Benzyl Alcohols Sensitized by TiO2 in CH3CN in the Presence of Ag2SO4. Kinetic Evidence for the Involvement of Adsorption Phenomena
Amori, Laura,Del Giacco, Tiziana,Rol, Cesare,Sebastiani, Giovanni V.
, p. 644 - 645 (1998)
X-Ring substituted benzyl alcohols are photooxidized to the corresponding aldehydes by TiO2 in CH3CN in the presence of Ag2SO4 and kinetic evidence suggests a changeover of the electron abstraction site from the aromatic moiety (X = 4-CH3O, 4-CH3, 4-Cl, H, 3-Cl) to the hydroxylic group (X = 3-CF3, 4-CF3), probably owing to the preferential adsorption of OH on TiO2.
Oxidative C-S Bond Cleavage of Benzyl Thiols Enabled by Visible-Light-Mediated Silver(II) Complexes
Hong, Boseok,Aganda, Kim Christopher C.,Lee, Anna
supporting information, p. 4395 - 4399 (2020/06/05)
The oxidative cleavage reaction of the C-S bond using singlet oxygen is challenging because of its uncontrollable nature. We have developed a novel method for the singlet-oxygen-mediated selective C-S bond cleavage reaction using silver(II)-ligand complexes. Visible-light-induced silver catalysis enables the controlled oxidative cleavage of benzyl thiols to afford carbonyl compounds, such as aldehydes or ketones, which are important synthetic components.
An Engineered Alcohol Oxidase for the Oxidation of Primary Alcohols
Heath, Rachel S.,Birmingham, William R.,Thompson, Matthew P.,Taglieber, Andreas,Daviet, Laurent,Turner, Nicholas J.
, p. 276 - 281 (2019/01/04)
Structure-guided directed evolution of choline oxidase has been carried out by using the oxidation of hexan-1-ol to hexanal as the target reaction. A six-amino-acid variant was identified with a 20-fold increased kcat compared to that of the wild-type enzyme. This variant enabled the oxidation of 10 mm hexanol to hexanal in less than 24 h with 100 % conversion. Furthermore, this variant showed a marked increase in thermostability with a corresponding increase in Tm of 20 °C. Improved solvent tolerance was demonstrated with organic solvents including ethyl acetate, heptane and cyclohexane, thereby enabling improved conversions to the aldehyde by up to 30 % above conversion for the solvent-free system. Despite the evolution of choline oxidase towards hexan-1-ol, this new variant also showed increased specific activities (by up to 100-fold) for around 50 primary aliphatic, unsaturated, branched, cyclic, benzylic and halogenated alcohols.