6-Amino-1-indanone (2.0516 g, 13.94 mmol) was used as starting material, which was dissolved in a 9:1 CHCl3/DMF solvent mixture (52 mL). Bromine (Br2, 0.71 mL, 13.94 mmol) was added slowly and dropwise under stirring conditions. The reaction mixture was continued to be stirred at room temperature for 1 hour. After completion of the reaction, the precipitate was collected by filtration and the filter cake was dried under vacuum to afford the target compound 6-amino-7-bromo-2,3-dihydro-1H-inden-1-one (2.7127 g, 63% yield). The product was detected by mass spectrometry (ESI(+)) and showed m/e 226,228 (M + H)+; mass spectrometry (ESI(-)) showed m/e 225,227 (M-H)-. 1H NMR (300 MHz, DMSO-d6) δ 7.28 (dt, 1H), 7.17 (d, 1H), 5.87 (br s, 3H), 2.89 ( m, 2H), 2.62 (m, 2H).
