Anodic Oxidation of Aliphatic and Aromatic Amides, Bisamides and Related Derivatives

The current comprehensive review covers four main parts, of which some are presented in the form of a personal account. 1. Anodic oxidation of a) N-alkyl and N,N-diallyl carbonyl moieties, b) Azacycloalkyl amides and the effect of ring-size on the outcome, c) Lactams, d) Sulfonamides, and e) The effect of a substituent R attached to carbonyl (N-CO-R) or sulfonamides (N-SO2R) on their oxidation potentials. 2. Anodic oxidation of aromatic amides, in particular of type Ph2CHCONHAr, lacking hydrogen(s) at the alpha-position to nitrogen. They undergo three types of bond-cleavage, yielding a variety of fragmentation products. 3. a) Anodic oxidation of symmetrical bisamides of type ZCONH(CH2)nNHCOZ (Z=Me, Ph, Ar; n=2-4) under constant current electrolysis, in methanol. For n=3, 4 they afford mostly mono- and dimethoxylation products. For n=2 they undergo ' CH2-CH2 ' bond cleavage to yield fragmentation products. b) Anodic oxidation of symmetrical bisamides of type ArCONH(CH2)2NHCOAr under controlled potential electrolysis, in acetonitrile, leads to gem-unsymmetrical bisamides of type ArCONHCH2NHCOMe as the major product, in fair yields. 4. Utilization of the anodic process in organic synthesis to form C-C bonds by both intra- and inetrmolecular processes; as well as C-O and C-N bonds for generating heterocycles. The present review/personal account covers the anodic oxidation of aliphatic amides, cyclic amides, aromatic amides and bisamides (as shown in the Scheme), under diverse experimental conditions. This anodic process is important from a synthetic point of view, yielding a variety of products that include ring-expansion, annulation, formation of heterocycles, and specific substitutions. image