The chemistry of azides derived from N-substituted phthalamic and tetrahalogenophthalamic acids

Abstract

Treatment of eight phthalisoimidium perchlorates with sodium azide gave N-substituted o-carbamoylbenzoyl azides (2), which yielded o-carbamoylphenyl isocyanates (4) when heated. The isocyanates derived from tertiary phthalamic acids formed 4-dialkyl ammonio-1,4-dihydro-2H-3,1-benzoxazin-2-one perchlorates (8) by the action of perchloric acid and acetic anhydride; those containing secondary amide groups cyclised to 3-alkyl-quinazoline-2,4-(1H,3H)-diones (11) at rates depending on the size of the alkyl radicals. Tetrachloro- and tetrabromo-phthalic anhydride reacted with amines to yield the corresponding amic acids, their salts, or N-substituted 3-amino-4-hydroxyphthalides. Ring-chain isomerism was also observed in the case of the azides derived from two tertiary tetrachlorophthalamic acids.