B. C. Sekhar, D. V. Ramana, S. R. Ramadas
Mar 1, 2001
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0
Influential Citations
4
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
The syntheses of tetracyclic 1,5-benzoxazepines 3a-e from heterocyclic (3-chloroaldehydes 1a-e and 2-aminophenol are reported herein (Scheme I). Attempted lithium aluminium hydride (LiAlH4) reduction of the imine double bond in 3a-e failed to furnish the corresponding saturated compounds 5a-e. Attempted catalytic hydrogenation of 3a-e in the presence of acetic acid and acetic anhydride gave surprisingly only the acetoxy derivatives 6a-e in high yields (Scheme II). Base catalysed hydrolysis of acetoxy derivatives 6a-e furnished, as expected, the corresponding phenolic derivatives 7a-e, in moderate yields. Attempted cyclofunctionalization of 3a-e either with mercaptoacetic acid or its methyl ester to obtain the new penta-cyclic heterocycles 4a-e was, however, not successful.