Use of NMR and Mass Spectrometry in Establishing the Structures of Ring Opening products of 3- Methyl- 4,1- Benzoxazepine-2,5- Dione in Acid and Basic Media

Abstract

3-Methyl-4,1-benzoxazepine-2.5-dione (I) when stirred for lr hours in methanolic solution with a few drops of 10 %. NaOH below 60 degreesC gave solid crystalline product (m.p. 100-102 degreesC, 51% yield). H-1 NMR and MS analysis confirmed structure (II) which suggest the cleavage of C-O bond but when (I) was treated with a few drops of 10% HCl under similar temperature yielded compound (III) as a liquid which gave evidence for C-N bond cleavage giving no traces of the former product (II).