Bromide ion → HCID 57522509, compound

Participants

Reaction Steps

To a stirred solution of 1-bromo-4-methoxy-5,6,8,9-tetrahydro-benzocyclohepten-7-one (20.0 g, 0.0743 mol) in sulfuric acid (200 mL, 4 mol) at 0° C. under an atmosphere of nitrogen was added potassium nitrate (7.89 g, 0.0780 mol) in portions. Note: When excess potassium nitrate is added, ipso substitution of the bromide is observed. After stirring for ˜15 min., an aliquot was removed and analyzed by HPLC indicating the completion of the reaction. Mixture was poured over ice water. A gummy solid formed which was dissolved in methylene chloride. The reaction mixture was transferred to a separatory funnel and the water layer removed. The organic phase was washed with saturated aqueous bicarbonate and water, dried over magnesium sulfate, filtered and concentrated in vacuo to an orange solid. Product was purified by ISCO chromatography on silica gel (350 g column) using ethyl acetate-hexane (10-100%). Fractions corresponding to product were combined and concentrated in vacuo to give 4-Bromo-1-Methoxy-2-nitro-5,6,8,9-tetrahydrobenzocyclohepten-7-one (18 g, 77%) as an orange solid. 1H NMR (CDCl3, 400 MHz) 8.04 (s, 1H), 3.90 (s, 3H), 3.25 (m, 2H), 3.15 (m, 2H), 2.64 (m, 4H).

Provenance & Evidence