Trifluoroacetic acid → 8-nitro-3,4-dihydro-2H-1,4-benzoxazepin-5-one

Participants

Reaction Steps

To a solution of 2-(2-tert-butoxycarbonyl amino-ethoxy)-4-nitro-benzoic acid (0.18 g, 0.00055 mol) in DCM (5 mL) was added TFA (0.5 mL) and stirred 1 hr. and evaporated. The residue was treated with anhydrous DMF (1 mL), N-methyl morpholine (0.50 mL 0.0046 mL) and 1-hydroxybenzotriazole hydrate (0.12 g, 0.00088 mol) and stirred 10 min. Benzotriazole-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (0.39 g, 0.00088 mol) was added, stirred 15 hrs. and evaporated. The residue was purified by ISCO chromatography giving 8-nitro-3,4-dihydro-2H-benzo[f][1,4]oxazepin-5-one (0.032 g, 26%) as a white solid. MP: 208-9° C.; 1H-NMR (DMSO-d6) δ 8.66 (s, 1H), 7.99-8.01 (d, 1H), 7.92-4 (d, 1H), 7.79-80 (d, 1H), 4.39-41 (m, 2H), 3.36-9 (m, 2H); LC/MS (ESI+): 209 (M+H).

Provenance & Evidence