8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one

31255-57-9

31251-41-9

General procedure for the synthesis of 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one from 3-(3-chlorophenylethyl)pyridine-2-carbonitrile: 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (10 g) obtained in step C was dissolved in trifluorosulfonic acid (80 ml) and the reaction was stirred at 60 °C for 1 hour. Subsequently, aqueous 6N hydrochloric acid (80 ml) was added slowly and dropwise at room temperature. The reaction mixture was refluxed for 1 hour and poured into ice water. The reaction solution was neutralized with 50% aqueous sodium hydroxide, the precipitate precipitated was separated, washed with water and recrystallized by solvent mixture of isopropanol/water (3:1) to afford the target product 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one. The mother liquor was concentrated and the residue was washed sequentially with water and chloroform to afford additionally 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (9.4 g, yield 94%).1H NMR (MeOD-d4) δ: 3.3-3.4 (m, 2H), 3.4-3.5 (m, 2H), 7.5 (m, 2H), 8.1-8.2 (m, 2H), 8.7 (d, 1H), 8.9 (d, 1H).