The Conversion of Secondary Amides to Tetrazoles with Trifluoromethanesulfonic Anhydride and Sodium Azide

Due to the interest in tetrazoles as medicinal agents, a new, mild one-step method for the conversion of amides to tetrazoles employing triphenylphosphine, diethyl azodicarboxylate, and trimethylsilyl azide was recently introduced. An alternate and equally simple method employing trifluoromethanesulfonic anhydride and sodium azide was devised. This method was used to synthesize a series of 1,5-substituted tetrazoles from readily available secondary amides. A 1H-substituted tetrazole was also synthesized by this method from an amide substituted with a cyanoethyl protecting group