1H-Inden-1-one, 5-bromo-6-fluoro-2,3-dihydro-

866862-24-0

866862-25-1

The general procedure for the synthesis of 5-bromo-6-fluoro-2,3-dihydro-1H-inden-1-one using 3-(3-bromo-4-fluorophenyl)propionic acid as starting material was as follows: 3-(3-bromo-4-fluorophenyl)propionic acid (3.5 g, 14.2 mmol) was dissolved in a solvent mixture of dichloromethane (25 mL) and N,N-dimethylformamide (0.5 mL) at room temperature. Oxalyl chloride (7.2 g, 56.7 mmol) was then added. The reaction mixture was continued to be stirred for 30 min before the solvent was removed by distillation under reduced pressure. The resulting residue was redissolved in dichloromethane (50 mL) and added slowly and dropwise to a refluxing suspension of pre-prepared aluminum trichloride (7.6 g, 56.7 mmol) in dichloromethane (200 mL). The reaction mixture was kept under reflux conditions for 90 min, followed by pouring into an ice/concentrated hydrochloric acid mixture to quench the reaction. Extraction was carried out with dichloromethane (3 x 200 mL) and concentrated under reduced pressure after combining the organic phases. Finally, the residue was purified by column chromatography (eluent 25% petroleum ether solution of ethyl acetate) to afford the target compound 5-bromo-6-fluoro-2,3-dihydro-1H-inden-1-one as a light yellow solid (2.1 g, 68% yield). Mass spectrometry analysis (ESI) showed that the calculated value of [M+H]+ was 229 (C9H6BrFO) and the measured value was 229.