ethyl 5-hydroxy-1-tosyl-2,3-dihydro-1H-benzo[b]azepine-4-carboxylate → 1-Tosyl-3,4-dihydro-1H-benzo[b]azepin-5(2H)-one

Participants

Reaction Steps

To a suspension of ethyl 5-hydroxy-1-tosyl-2,3-dihydro-1H-benzo[b]azepine-4-carboxylate (30 g, 8.04 mmol) in glacial acetic acid (180 mL), conc. hydrochloric acid (30 mL), ethanol (60 mL) water (30 mL) and conc. sulphuric acid (15 mL) were added at 10-15° C. The reaction mixture was warmed to room temperature and then heated to reflux for 15-16 h. The reaction mixture was cooled to room temperature and poured on to ice. A precipitate formed which was filtered and washed with water (200 mL×3) and dried under reduced pressure to afford 1-tosyl-3,4-dihydro-1H-benzo[b]azepin-5(2H)-one (14 g, 56%). 1H NMR: (400 MHz, CDCl3) δ: 7.71-7.69 (1H, d, J=9.6 Hz), 7.60 (2H, d, J=8.4 Hz), 7.54 (1H, t, J=8.4 Hz), 7.48 (1H, d, J=7.2 Hz), 7.40 (1H, t, J=7.2 Hz), 7.28 (2H, d, J=8.4 Hz), 3.87 (2H, t, J=6.4 Hz), 2.42 (3H, s), 2.42 (2H, m), 1.98 (2H, m).

Provenance & Evidence