123903-24-2Relevant articles and documents
A New Oxidizing System for Aromatic Alcohols by the Combination of N-Oxoammonium Salt and Electrosynthesized Tetraalkylammonium Tribromide
Inokuchi, Tsutomu,Matsumoto, Sigeaki,Fukushima, Mitsuhiro,Torii, Sigeru
, p. 796 - 800 (2007/10/02)
A combination of 2,2,6,6-tetramethyl-1-piperidinyloxyl and tetraalkylammonium tribromides (R4NBr3), which are available from the corresponding tetraalkylammonium bromides via electrooxidation with potassium bromide, has proved to be useful for oxidations of primary and secondary alcohols to the corresponding aldehydes and ketones, respectively.The oxidation reaction proceeds smoothly even with a 0.5-1.0 molpercent of N-oxyl compounds and 1.5-2.0 equivalents of tetraalkylammonium tribromides in an aqueous-organic two-phase solution buffered at pH 8.0-8.6.This recyclable oxidant/co-oxidant combination system may involve the formation of N-oxoammonium salts, actual oxidizing agents of alcohols, by the action of hypobromite species generated from R4NBr3 in the binary solution.Utility of the method is highlighted by the selective oxidation of benzylic alcohols bearing electron-releasing groups on the aromatic nucleus to the corresponding aldehydes or ketones without any bromination and overoxidation.
A Selective and Efficient Method for Alcohol Oxidations Mediated by N-Oxoammonium Salts in Combination with Sodium Bromite
Inokuchi, Tsutomo,Matsumoto, Sigeaki,Nishiyama, Tokio,Torii, Sigeru
, p. 462 - 466 (2007/10/02)
The oxidation of primary and secondary alcohols leading to aldehydes, carboxylic acids, and ketones has been carried out in a N-oxoammonium salts-NaBrO2 system.Sodium bromite as a stoichiometric oxidizing reagent activates N-oxyl compounds (recycling catalysts) to their N-oxoammonium salts in a weakly basic medium, which oxidize primary hydroxyl groups preferentially rather than secondary ones to the corresponding aldehydes.Calcium hypochlorite is used as an alternative terminal oxidant in the same media.The procedure, applicable to the selective formation of γ- and δ-lactones, β-hydroxy aldehydes, and 2-acetoxy ketones, is advantageous in terms of reagent cost, safety, and ease of operation.
