Safer and Convenient Synthesis of 3,4-Dicyanofuroxan

A safer, convenient, cost-effective, and scalable synthesis for 3,4-dicyanofuroxan (C₄N₄O₂) is described. Dropwise treatment of a well-stirred suspension of cyanoacetic acid in dichloromethane with concentrated mixed acid (HNO₃/H₂SO₄) affords dicyanofuroxan in 72% yield and in 84% purity after liquid chromatography analysis. Single crystal X-ray diffraction studies further confirm the product and yield its molecular conformation and crystal packing. During the dropwise addition of mixed acid, self-heating occurs, and this event is necessary for the reaction to adequately proceed. However, such self-heating is limited to the refluxing temperature of dichloromethane. This new method supersedes the previous methods used to synthesize dicyanofuroxan, which were low-yielding and of significantly lower purity, irreproducible, relied on expensive reagents, and suffered from dangerous exothermic profiles.