The Effect of Length of Spacer on the Anodic Oxidation of Bisamides

Previously we studied the anodic oxidation of different types of amides, including cyclic ones [1-3]. Recently we investigated [4] the anodic oxidation of bisamides (from diaminoalkanes) involving 2-4 methylene groups as spacers between the two amide functionalities. Those with 3 and 4 methylene groups behave similar to monoamides. They both undergo mostly mono- and dimethoxylations at the alpha-position to 'N' atom. However, when the spacer contains two methylene groups only, the anodic process affords mostly fragmentation products due to CH2-CH2 bond cleavage: RCONHCH2OCH3 exclusively, or along with RCONHCHO, depending on the supporting electrolyte used. The scheme below describes the outcome in both cases: References [1] Golub T.; Becker J. Y., Org. Biomol. Chem. 2012, 10, 3906-3912. [2] Golub T.; Becker J. Y., J . Electrochem. Soc. 2013, 160, G3123-G3127. [3] Golub T.; Becker J. Y., Electrochim. Acta 2015, 173, 408–415. [4] Golub T.; Becker J. Y., Beilstein J. Org. Chem. 2018, 14, 861–868. Figure 1