Electrochemical thiocyanation of barbituric acids

Abstract

The electrochemical thiocyanation of barbituric acids with NH₄SCN was disclosed in an undivided cell under constant current conditions. The electrosynthesis is the most efficient at a record high current density (j_anode ≈50–70 mA cm⁻²). NH₄SCN has a dual role as the source of the SCN group and as the electrolyte. Electrochemical thiocyanation of barbituric acids starts with the generation of (SCN)₂ from the thiocyanate anion. The addition of thiocyanogen to the double bond of the enol tautomer of barbituric acid gives thiocyanated barbituric acid. A variety of thiocyanated barbituric acids bearing different functional groups were obtained in 18–95% yields and were shown to exhibit promising antifungal activity.