1b) Synthesis of 6-bromo-2-quinolinecarboxylic acid: Concentrated sulfuric acid (0.75 L) was slowly added to an aqueous (1.75 L) suspension of 6-bromo-2-(tribromomethyl)quinoline (350 g, 0.76 mol) over a period of 15 min under stirring conditions. The reaction mixture was heated at 150 °C (oil bath temperature) for 5 hours. After completion of the reaction, the mixture was cooled, the precipitate was collected by filtration, washed with water and dried to give 6-bromo-2-quinolinecarboxylic acid solid (127.6 g). The filtrate was diluted with water (3 L) to further precipitate a second product (55.7 g) in a combined yield of 183.3 g in 96% yield. The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 8.50 (d, J = 9 Hz, 1H), 8.38 (d, J = 2 Hz, 1H), 8.13 (d, J = 9 Hz, 1H), 8.06 (d, J = 9 Hz, 1H), 7.96 (m, 1H). an ES-LCMS assay showed m/z 253 ([M + H] +).
