Mechanism of oxidation of Schiff bases to oxaziranes by peroxy acids. II. In aprotic solvents

Abstract

The oxidation of N-p-nitrobenzal-f-butylamine (II) with m-chloroperoxybenzoic acid in the aprotic solvents methylene chloride and dioxane gave a kinetic law suggesting a nucleophilic attack by the Schiff base on a peroxy acid dimer. We suggest a five-membered ring for the dimer in the transition state.The mechanism for the oxidation of Schiff bases (>C=N-) with peroxybenzoic acids in i-butyl alcohol was proposed as follows,2 where HY denotes a ArC03H

Isolation of Nicotinic Acid (Vitamin B3) and N-Propylamine after Myosmine Peroxidation

“…The pyridine substitutent on the imine C of 1 may additionally support the oxirane–oxazine rearrangement. The fact that oxaziranes 2a – 2d are unstable when isolated by conventional techniques may be related to an earlier report where efforts to prepare phenyl-substituted oxaziranes were unsuccessful because of their instability. Since phenyl or pyridyl groups are known to have electron-withdrawing properties, attachment of these substituents to the 2-position of the oxazirane could destabilize the ring system.…”

“…Different substituents on azomethines modify the polarization of their CN group in reactions with ROS, such as superoxide, hydrogen peroxide, and hydroxyl radicals. Studies on oxazirane cleavage reported the occurrence of amines or ammonium-derived compounds and corresponding aldehydes as the main reaction products. − …”

“…The 3-pyridylaldehyde, a possible intermediate further oxidation of 9 to 10, was also not found in rat metabolism studies and in the peroxidation assay. Formation of 9 imposing on oxazirane decomposition seems not possible in one reaction step but requires additional The fact that oxaziranes 2a−2d are unstable when isolated by conventional techniques may be related to an earlier report 22 where efforts to prepare phenyl-substituted oxaziranes were unsuccessful because of their instability. Since phenyl or pyridyl groups are known to have electronwithdrawing properties, attachment of these substituents to the 2-position of the oxazirane could destabilize the ring system.…”