Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis

In general, bisamides derived from diamines and involving 3 and 4 methylene groups as spacers between the two amide functionalities behave similar to monoamides upon anodic oxidation in methanol/LiClO₄ because both types undergo majorly mono- and dimethoxylations at the α-position to the N atom. However, in cases where the spacer contains two methylene groups only the anodic process leads mostly to CH₂-CH₂ bond cleavage to afford products of type RCONHCH₂OCH₃. Moreover, upon replacing LiClO₄ with Et₄NBF₄ an additional fragmentation type of product was generated from the latter amides, namely RCONHCHO. Also, the anodic process was found to be more efficient with C felt as the anode, and in a mixture of 1:1 methanol/acetonitrile co-solvents.