Four
5-aryl-2,3-dihydro-1,4-benzoxazepines (5a-d), with electron-releasing
substituents, were prepared by a Bischler-Napieralski-type reaction of
N-(2-aryloxyethyl)benzamides with phosphorus oxychloride in butanenitrile or
ethanenitrile. Analogous 2,3-dihydro-1,4-benzoxazepines (12a, b), with hydrogen
only or a chlorine substituent in the fused aromatic ring, were prepared by C-N
ring-closure reactions. Cyclization of a dilute solution of
N-[3-(3-methoxyphenoxy)propyl]benzamide (21) with phosphorus oxychloride in
ethanenitrile gave a 40% yield of 9-methoxy-6-phenyl-3,4-dihydro-
2H-1,5-benzoxazocine (22). The seven- and eight-membered cyclic imines were
converted into their methiodide salts (6a-d), (15a,b) and (24). These were
reduced with sodium tetrahydroborate to yield the
5-aryl-4-methyl-2,3,4,5-tetrahydro-1,4-benzoxazepines (7a-d) and (l6a,b), and
the 9-methoxy- 5-methyl-6-phenyl-3,4,5,6-tetrahydro-2H-1,5-benzoxazocine (25).
These products were prepared for use as starting materials in ring-expansion
reactions through the Meisenheimer rearrangement.
