Oxidation of amides

Various oxidations of amides or carbamates can also generate acyliminium ions. An electrochemical oxidation forms a-alkoxy amides and lactams, which then generate... 

Direct oxidation of amides can also lead to Hofmann-type rearrangement with formation of amines or carbamates. One reagent that is used is Pb(02CCH3)4. 

The values of BDE of the weakest C—H bonds in amides, we considered, are by 10-20kJ mol 1 higher than those in the corresponding amines. Naturally, this difference influences the oxidation of amides. 

Amides have carbonyl group and nitrogen atom. Both these groups can form hydrogen bonds with O—H and N—H-containing compounds. Therefore, hydroperoxides form associates with amides via hydrogen bonding. This association influences the kinetics of the oxidation of amides and decay of hydroperoxides. 

Amides, as amines and hydrocarbons, are oxidized by dioxygen according to the chain mechanism [1], The initiated oxidation of amides proceeds according to the classical scheme... 

Hydroperoxides formed due to the oxidation of amides are decomposed into free radicals and accelerate oxidation. Hydroperoxides form hydrogen bonds with amides. The enthalpies, entropies, and equilibrium constants of hydrogen bonding are presented in Table 9.7. 

I n addition to the direct oxidation of simple amides, indirect oxidations of amides have proven useful for synthesizing chiral starting materials. Such reactions are often employed when direct electrolyses... 

Indirect oxidations of amides by electrogenerated C1+ , which gives an adduct with the amide nitrogen, has been used to synthetize chiral building blocks (Scheme 37) [55]. 

The anodic oxidation of amides and carbamates is one of the most general and efficient electrochemical reactions known [115]. The primary intermediate... 

Oxidation of amides at a rotating platinum electrode in acetonitrile with tetraethylammonium 4-toluenesulphonate as electrolyte. 

These reactions proceed via the a-acetoxy derivative, which then forms the en-amide. Furfrier oxidation of the enamide gives the isolated products. A synthesis of cu-pseudoconhydrine 29 from 2-propylpiperidine illustrates both this process and also the regioselectivity in oxidation of amides, which favours attack on a methylene rather than a methine carbon atom [126],... 

Abstract This chapter principally concerns oxidations of organic substrates containing N, O, S, P, As and Sb. Oxidations of amines are covered first, including primary amines to nitriles or amides secondary amines to imines or other products tertiary amines to N-oxides or other prodncts (Section 5.1) and the oxidation of amides (5.2). Oxidation of ethers to esters or lactones follows (5.3), then of sulfides to sulfoxides or sulfones (5.4) and of phosphines, arsine and stibines to their oxides (5.5). A final section (5.6) concerns such miscellaneous oxidations not covered by other sections in the book. 

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