3H-azepines and related systems part 3. Mono- and bis- 2-alkoxy-3H-azepine-3-carboxylates and -3-carboxamides by photolysis of mono- and di-o-azidobenzoyl derivatives of glycols and diamines. Some acyclic crown ether analogues.
The mono-o-azidobenzoates (1a–c) of mono-, di-, and tri-ethyleneglycol, on photolysis in methanol-tetrahydrofuran, yield the corresponding glycol monoesters (2a–c; R = H) of 2-methoxy-3H-azepine-3-carboxylic acid. A bis-3H-azepine-3-carboxylate (4a) is obtained from ethylene glycol di-o-azidobenzoate (3a). Similarly, bis-3H-azepine-3-carboxamides (12)–(14) are obtained by ring-expansion of the di-o-azidobenzoyl derivatives of ethylene, and o- and p-phenylene diamines. Photolysis of the o-azidobenzoates of 2-ethoxyethanol (6a) and diethylene glycol monomethyl ether (6b) in mono- or di-ethylene glycol, or their monoalkyl ethers and tetrahydrofuran, produces 2-alkoxy-3H-azepine-3-carboxylates (5a), (5b), (7), and (8) one of which, (8), has metal cation complexing properties. Irradiation of β-hydroxyethyl o-azidobenzoate (1a) in tetrahydrofuran furnishes a diazepino 14-crown-4 analogue (18), whereas on spray pyrolysis indazolo[2,1-a]indazole-6,12-dione (20) is obtained.