Cathodic reduction of caffeine: synthesis of an amino-functionalized imidazole from a biobased reagent

The electrochemical reduction of caffeine, never carried out previously, yielded in DMF-Et 4 NBF 4 N -formyl- N,1-dimethyl-4-(methylamino)-1 H -imidazole-5-carboxamide, a highly functionalized imidazole product derived from the opening of the uracil ring. This reactivity is different from that of the methylated salt of caffeine, the cathodic reduction of which leads to the opening of the imidazole ring. Moreover, the product obtained by cathodic reduction, formylated at the exocyclic amide nitrogen, is different from that formed by treatment in an aqueous solution of sodium hydroxide followed by formylation. The latter is formylated at the exocyclic amine nitrogen.