Methyltrioxorhenium Catalyzed Oxidation of Secondary Amines to Nitrones: N ‐Benzylidene‐benzylamine N ‐Oxide

Abstract

N‐ Benzylidene‐benzylamine N‐oxide Methyltrioxorhenium Urea hydrogen peroxide Dibenzylamine

Crystal structure of (Z)-N-benzylidene-1-phenylmethanamine oxide hydrogen peroxide monosolvate

“…It is known that nitrones R 1 -CH N(O)-R 2 [R 1 , R 2 = aryl (Ar) or alkyl (Alk)] are readily available by oxidation of secondary amines using hydrogen peroxide (Goti et al, 2005). We supposed that the combination of oxidizing and cocrystallizing properties of hydrogen peroxide might afford an opportunity to obtain nitrone peroxosolvates in one step.…”

Tandem Addition/Cyclization of Alkynylzinc Reagents to Enantiopure 2‐tert‐Butyl‐3,5‐dimethyl‐2,3‐dihydroimidazol‐4‐one N‐Oxide: Potential Precursors of Quaternary α‐Amino Acids

“…[19] Note that Baldwin and Long [19] successfully oxidized 1a to 2a with urea/hydrogen peroxide (UHP) using methyltrioxorhenium (MTO) in methanol as a catalyst. [8] We observed that our samples of 2a decomposed on storage. Moreover, an enantiopure solid sample of 2b stored at 20°C for 3 months lost optical activity (without decomposition).…”

“…of UHP and MTO. [7,8,27] Simple filtration through a pad of silica produced the corresponding N-hydroxylamines 3; the sole impurity was nitrone 2. At this stage, N-hydroxylamines 3 could be isolated by chromatography (yields 3a: 76%; 3b: 65 %) and stored for months without any loss of optical activity.…”

Synthesis of α‐Acyloxynitrones and Reactivity towards Samarium Diiodide

“…Among the synthetic approaches to prepare endocyclic nitrones, oxidation of pyrrolidines and piperidines using hydrogen peroxide in the presence of catalysts, dimethyldioxirane, Davis oxaziridine,[10e], or methyltrioxorhenium suffers from poor regioselectivity. Similarly, the oxidation of N ‐hydroxypyrrolidines and N ‐hydroxypiperidines using HgO or MnO 2 generally yields mixtures of regioisomers.…”