4.1.16 Synthesis of 5-bromo-8-aminoquinoline (21): 8-aminoquinoline (1.0 g, 6.94 mmol) was dissolved in 46.0 mL of acetonitrile, and N-bromosuccinimide (NBS, 605 mg, 3.40 mmol for the first portion) was added in batches. The reaction mixture was stirred at 25 °C for 15 min and then the second portion of NBS (667 mg, 3.75 mmol) was added. Stirring of the reaction mixture was continued at 25°C. After completion of the reaction, the solvent was removed by evaporation under reduced pressure and the residue was dissolved in ethyl acetate (EtOAc) and washed with deionized water (3 x 50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified by silica gel fast column chromatography (eluent: petroleum ether solution of 10% ethyl acetate) to afford 5-bromoquinolin-8-amine as a yellow amorphous solid in 51% yield.1H NMR (300 MHz, CDCl3) δ 8.76 (d, 1H, J=6.0 Hz), 8.43 (d, 1H, J=9.0 Hz), 7.56 (d, 1H. J=12.0 Hz), 7.48 (q, 1H, J=3.0 Hz), 6.80 (d, 1H, J=6.0 Hz); ESI-MS m/z 222.9 [M+H]+.
