Reactions of 6-(dichloromethylene)cyclohexa-2,4-dien-1-alkylimines with amines

Chlorination of 2,1-benzisothiazoline 2,2-dioxides (benzosultams) with hexachloroethane under phase-transfer catalysis condition in the presence of 50% aqueous NaOH and tetraalkylammonium salt gives 3,3-dichlorobenzosultams in good yields. Thermal extrusion of SO2 from 3,3-dichloropyridosultams generates dichloro derivatives of aza-ortho-xylylenes which do not enter [4+2] cycloaddition reactions, but add amines to form amidines. With aromatic diamines and aminophenols, benzimidazole and benzoxazole derivatives are formed in good yields.