Step 1: Synthesis of 9-bromononanoic acid
To an acetone (27 ml) solution of 9-bromo-1-nonanol (1.50 g, 6.72 mmol) cooled to 0°C, saturated NaHCO3 solution (9 ml), NaBr (0.14 g, 1.34 mmol), and 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) (0.10 g, 0.67 mmol) were added sequentially. Trichloroisocyanuric acid (3.1 g, 13.44 mmol) was then added in batches. The reaction mixture was stirred at 0 °C for 30 min, then brought to room temperature and continued stirring for 3 h. The reaction was carried out at 0 °C for 2 min. After completion of the reaction, the mixture was cooled to 0 °C, 2-propanol (8 ml) was added slowly and stirring was continued at 0 °C for 30 min. A white precipitate was collected by filtration and the filtrate was concentrated under reduced pressure. H2O (10 ml) and CH2Cl2 (10 ml) were added to the residue to separate the two phases. The aqueous phase was extracted with CH2Cl2 (2 x 10 ml), the organic phases were combined, dried with Na2SO4 and concentrated under reduced pressure to give 1.60 g (yield: 100%) of 9-bromononanoic acid as a white solid.1H NMR (300 MHz, DMSO) δ 3.49 (t, 2H), 2.23-2.08 (m, 2H), 1.84-1.68 (m, 2H) , 1.57-1.14 (m, 10H).
