Synthesis of Disulfides Using Basic Oxidizing Agent NaOH/Formamide With 5‐Amino‐4‐thiocyanatopyrazoles

ABSTRACT A novel basic oxidizing method for the synthesis of disulfides containing a 5‐aminopyrazole moiety was successfully developed using NaOH/formamide as the oxidizing agent, starting from 5‐amino‐4‐thiocyanatopyrazoles. This method can be widely applied to various substituted 5‐amino‐4‐thiocyanatopyrazole derivatives. Compared with traditional oxidative methods for sulfur–sulfur bond formation, this newly developed method avoided the use of expensive metal catalysts, strong acidic oxidants, or photocatalytic aerobic conditions. In addition, 5‐amino‐4‐thiocyanatopyrazoles were treated with 1.0 equiv. of NaOH in various alcoholic solvents, including MeOH, EtOH, n ‐PrOH, i ‐PrOH, and n ‐BuOH, to afford 5‐amino‐4‐(alkylthio)pyrazoles.