A solution of 1,1-dimethylethyl 7-(4-amino-3-nitrophenyl)-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate (example 8, step 1) (2.3 g, 6.0 mmol), in acetic acid (20 mL) and ethyl acetate (20 mL) was hydrogenated at 45 psi over 10% Pd—C (1.0 g) for 1 h using a Parr apparatus. The catalyst was filtered off and the filtrate was concentrated to give 1,1-dimethylethyl 7-(3,4-diaminophenyl)-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate (2.0 g, 94% yield) as a light yellow oil. MS (EI) for C20H25N3O3: 356 (MH+).
