Improvement upon a Largely Forgotten Method for the Synthesis of N-Alkyl Urazoles

N-Alkyl urazoles are important heterocyclic compounds that serve as important precursors to potent N-alkyl 1,2,4-triazoline-3,5-dione electrophiles. Traditional methods for urazole synthesis have relied upon the use of toxic isocyanates. We have modified and optimized an overlooked and poorly-described literature method for the synthesis of urazoles that now avoids the use of isocyanates, limits the use of solvents, and provides urazoles without the need for purification steps. A variety of urazoles are afforded in good to high yields.