Acetic Acid → N-(6-Bromo-indan-2-yl)-N-propyl-propionamide

N-Indan-2-yl-N-propyl-propionamide (Preparation 13, 1 g, 4.32 mmol) was dissolved in dichloromethane (100 mL). Glacial acetic acid was added to adjust the pH to 4. This was followed by the addition of bromine (0.4 ml, 7.78 mmol). The solution was stirred at room temperature for 8 h. Additional bromine (0.2 ml, 3.89 mmol) was added and the solution was refluxed for 18 h. Since the reaction was not complete another portion of bromine (0.2 ml, 3.89 mmol) was added and the reaction mixture was refluxed for another 4 h. The organic layer was extracted with aqueous Na2CO3 (10%) and the layers were separated. The organic layer was dried (MgSO4). The solvent was evaporated and the remaining crude product was chromatographed (SiO2) with n-hexane:ethyl acetate (4:1) as eluant. The pure fractions were pooled yielding 0.45 g (34%) of N-(6-Bromo-indan-2-yl)-N-propyl-propionamide. 1H NMR (300 MHz, CDCl3) δ 0.85 (t, 3H), 1.15 (t, 3H), 1.50-1.65 (m, 2H), 2.30-2.50 (m, 2H), 2.90-3.25 (m, 6H), 4.70-5.10 (m, 1H), 7.00-7.10 (t, 1H), 7.25-7.40 (m, 2); MS m/e 309 (1, M+), 116 (100), 115 (92), 194 (57), 196 (55).