The heterocyclic derivatives,
8,9-dimethoxy-3-methyl-1-phenyl-3,4,5,6- tetrahydro-1H-2,3-benzoxazocine(3a)
and 9,10-dimethoxy-3-methyl-1- phenyl-1,3,4,5,6,7-hexahydro-2,3-benzoxazonine
(3b),examples of two new ring systems, have been prepared by Meisenheimer
rearrangement of the corresponding 2-benzazepine and 2-benzazocine N-oxide
derivatives (2a) and (2b). The Bischler-Napieralski-type
cyclization reaction was used in the preparation of the tertiary amine
precursors of these N-oxides reaction conditions for the cyclization were
critical and phosphorus oxychloride in refluxing butanenitrile was found to
give the best yields of the seven- or eight-membered cyclic imine
intermediates. Reductive cleavage of the benzoxazocine derivative (3a) with
zinc in acetic acid followed by N-methylation gave the expected product, [2-{3-
(dimethylamino)propyl}-4,5-di-methoxyphenyl]phenylmethanol (12). The crystal and molecular structure of
(3a) has been determined by X-ray crystallographic analysis.
