Generation and reactions of aza- ortho-xylylenes in the injector of GC/MS system

Abstract

Nitro derivatives of 2,1-benzisothiazoline 2,2-dioxide (benzosultams) undergo thermal elimination of sulfur dioxide yielding very reactive, non-isolable azo- ortho-xylylenes. It was found that this reaction can be performed in the injector of the gas chromatograph at 300 – 350°C and the formed aza- ortho-xylylenes can be trapped by appropriate reagents added to the injected solution. In the preliminary experiments aza- ortho-xylylenes were reacted with dienophiles (methyl acrylate, dimethyl maleate, vinyl acetate, N-phenylmaleimide etc.) resulting in the formation of the [4+2] cycloaddition reaction products, and also with nucleophilic reagents (alcohols, amines) to give appropriate adducts. In the absence of the trapping reagent dimers of aza- ortho-xylylenes were formed.