Categories: N-O Bond Formation >
Synthesis of N-oxides of pyridines and related compounds
Sodium percarbonate is an ideal and efficient oxygen source for the oxidation of tertiary nitrogen compounds to N-oxides in excellent yields in the presence of various rhenium-based catalysts under mild reaction conditions.
S. L. Jain, J. K. Joseph, B. Sain, Synlett, 2006, 2661-2663.
Sodium perborate in acetic acid is an effective reagent for the oxidation of aromatic aldehydes to carboxylic acids, iodoarenes to (diacetoxyiodo)arenes, azines to N-oxides, and various sulphur heterocycles to S,S-dioxides. Nitriles undergo smooth oxidative hydration to amides when aqueous methanol is employed as solvent.
A. McKillop, D. Kemp, Tetrahedron, 1989, 45, 3299-3306.
Urea-hydrogen peroxide adduct (UHP) is stable, inexpensive and an easily handled reagent. UHP is used in an efficient solid state oxidation of different organic molecules: hydroxylated aldehydes and ketones (to hydroxylated phenols), sulfides (to sulfoxides and sulfones), nitriles (to amides) and nitrogen heterocycles (to N-oxides).
R. S. Varma, K. P. Naicker, Org. Lett., 1999, 1, 189-191.
Use of a solvent with greater density than the fluorous phase is an alternative to the U-tube method in phase-vanishing reactions in cases where both reactants are less dense than the fluorous phase.
N. K. Jana, J. G. Verkade, Org. Lett., 2003, 5, 3787-3790.