Reactive intermediates. Part XVII. Conversion of peri-substituted azidonaphthalenes into naphthoxazoles, 1,2-dihydrobenz[cd]indazoles and perimidines

Abstract

Pyrolysis of 1-acylamino-8-azidonaphthalenes gives 2-substituted 9-aminonaphth[1,2-d]oxazoles by an intramolecular acid-catalysed decomposition of the azide system with concomitant nucleophilic attack by the amide oxygen atom at the naphthalene 2-position. Similar treatment of compounds in which the amide hydrogen atom has been replaced by a methyl or an acetyl group leads to formation of 1,2-dihydrobenz[cd]indazole derivatives. Mechanisms for the formation of these indazoles, and of perimidines also formed in the decompositions, are discussed.