Economic, One-Pot Synthesis of Diethyl Furoxan Dicarboxylate

Diethyl furoxan dicarboxylate (DFD) is a starting material for fields as diverse as drug discovery, energetics, and any application where a furoxan or furazan may be desired. As with many disubstituted furoxans, they are synthesized via the dimerization of the appropriate nitrile oxide. Past procedures to form DFD involve low-yield destructive nitrations, multiple steps, halogenated solvents, or heavy or precious metals. Although these methods are functional enough for lab-scale preparations of DFD, they do not hold up well for economical scale-up. Our reported procedure improves the synthesis of DFD such that it is available from economical and commercially available starting materials in a single-step, one-pot, high-yield (98.5%) synthesis of material with a trivial workup in high purity (98.2% by H-1 quantitative NMR against a 2,4,6-trimethoxy-1,3,5-triazene standard). This improved procedure requires no organic solvents or heavy metals and is the most scalable preparation for this material to date.