Solvent-free mechanochemical chlorination of pyrazoles with trichloroisocyanuric acid

Abstract

A solvent-free, rapid and operationally simple method for the chlorination of pyrazoles with trichloroisocyanuric acid to access 4-chloropyrazole derivatives is described. This high-yielding protocol avoids tedious column chromatography and reduces solvent consumption. Mechanistic studies suggested an electrophilic aromatic substitution mechanism. This system also gives good green chemistry metrics.