A convenient approach to arenediazonium tosylates

Abstract

Herein we present a mild, simple and environmentally friendly diazotization protocol of aromatic and heteroaromatic anilines into stable diazonium salts that surpass previously reported procedures. The reaction proceeds with tert-butyl nitrite in the presence of an equimolar amount or small excesses of p-toluenesulfonic acid in ethyl acetate, at room temperature. o-Phenylenediamines yield benzotriazolium tosylates. The resulting diazonium tosylates proved to be bench stable over a long period of time. In selected examples, diazonium salts were let to react with activated aromatic compounds including 2-naphthol and aniline derivatives into the corresponding azo dyes.