An Efficient, Inexpensive, and Shelf-Stable Diazotransfer Reagent:  Imidazole-1-sulfonyl Azide Hydrochloride

The design and synthesis of a new diazotransfer reagent, imidazole-1-sulfonyl azide hydrochloride, are reported. This reagent has proven to equal triflyl azide in its ability to act as a "diazo donor" in the conversion of both primary amines into azides and activated methylene substrates into diazo compounds. Crucially, this reagent can be prepared in a one-pot reaction on a large scale from inexpensive materials, is shelf-stable, and is conveniently crystalline.