Acylarylnitrosamines. Part 13. Promotion of ionic reactions of o- and p-chloro-, o- and p-acetoxy-, and o-acetylthio-N-nitrosoacetanilides. Formation of hydroxybenzenediazonium salts, the carbene 2-oxocyclohexa-3,5-dienylidene, and 1,2,3-benzothiadiazole

Abstract

New ionic reactions are reported of several arenediazonium salts (derived from corresponding acylarylnitrosamines), involving suppression of the normal radical chain decomposition by addition of 1,1-diphenylethene. Thus p-chloro-N-nitrosoacetanilide (p-CI-NNA) gave p-hydroxybenzenediazonium chloride (27%) and acetic anhydride (62%), and o-CI-NNA gave o-chlorobenzenediazonium chloride (62%) and acetic anhydride (62%). That these reactions proceed via unprecedented nucleophilic substitution of aromatic chloride by acetate ion, followed by ionic deacetylation of the resultant o- or p-acetoxybenzenediazonium ions to give acetic anhydride and 2- or 4-diazocyclohexadienone, follows from the results of corresponding 1,1-diphenylethene-promoted reactions of o- and p-AcO-NNA. Decomposition of the former in boiling xylene gave 2-cyclopentadienyldiene-1,3-benzo-dioxole (22%), formed by reaction of 2-diazocyclohexadienone with the product of its decomposition, the carbene 2-oxocyclohexa-3,5-dienylidene.

Decomposition of o-AcS-NNA in benzene gives 1,2,3-benzothiadiazole (70%).