Synthesis and Transformations of Nitrones for Organic Synthesis

Abstract

Nitrones are important compounds and are highly useful in many aspects. The first part describes the methods for synthesis of nitrones, which are useful and environmentally friendly. Catalytic oxidations, condensations, and other useful reactions are described. The nitrones thus obtained are key intermediates for the synthesis of biologically important nitrogen compounds. The second part describes the fundamental transformations of nitrones, which will provide the strategies and means for the construction of nitrogen compounds. The reactions with nucleophiles or radicals, C–H functionalization, and various addition reactions are described. The last reactions are particularly important for highly selective carboncarbon bond formations. 1,3-Dipolar cycloaddition reactions are excluded because the size of the review is limited and excellent reviews have been published in Chemical Reviews.

Synthesis of Pyrrolidine Monocyclic Analogues of Pochonicine and Its Stereoisomers: Pursuit of Simplified Structures and Potent β-N-Acetylhexosaminidase Inhibition

“…Molecules 2020, 24, x FOR PEER REVIEW 3 of 24 Synthesis of acetamide modified pyrrolidines generally rely on asymmetric synthesis from achiral starting materials or begin with carbohydrate precursors [32]. In the second strategy, carbohydrate-derived nitrones have significant advantages due to their ready chirality, availability and versatile chemistry [47,48]. In this work, polyhydroxylated nitrones A-H ( Figure 3) were readily prepared from the enantiomers of xylose, arabinose, lyxose and ribose by literature methods [16,[49][50][51].…”

Synthesis of Novel Cyclic Nitrones with gem‐Difluoroalkyl Side Chains Through Cascade Reactions

“…Further, nitrones have been employed also as therapeutic agents in the treatment of diseases related to oxidative stress such as neurodegeneration,, ischemic stroke,, cardiovascular diseases, and cancer . In addition, nitrones are valuable intermediates in organic synthesis affording efficiently various types of useful heterocyclic, as well as acyclic molecules . On the other hand, it is well recognized that introduction of fluorine in organic molecules can be used for a fine tuning of their physical, chemical and biological properties .…”

On the Nitrogen Inversion of Isoxazolidin-5-ones

“…Isoxazolidines, which are saturated five-membered heterocycles that contain N-O bonds, have served as strategic intermediates in synthetic organic chemistry. 1) Although this moiety itself is scarcely found in the structures of natural products, the labile N-O bond provides a facile way of installing 1,3-aminoalcohol units in molecular frameworks. 2) This heterocycle has also received particular attention in physical organic chemistry because, as a unique property of an isoxazolidine, its nitrogen inversion is slower than that of pyrrolidine.…”

“…1) Although this moiety itself is scarcely found in the structures of natural products, the labile N-O bond provides a facile way of installing 1,3-aminoalcohol units in molecular frameworks. 2) This heterocycle has also received particular attention in physical organic chemistry because, as a unique property of an isoxazolidine, its nitrogen inversion is slower than that of pyrrolidine. 3,4) Consequently, a range of N-alkyl isoxazolidines has been examined by NMR spectroscopy with the aim of determining the activation energies of these inversion processes.…”