General procedure for the synthesis of 4-bromo-1-naphthalenecarboxylic acid from (4-bromonaphthalen-1-yl)methanol: A mixture of chromic anhydride (1.81 g, 18.1 mmol) and concentrated hydrochloric acid was added slowly and dropwise to a solution of (4-bromo-1-naphthalenyl)methanol (1.329 g, 6.027 mmol) in acetone (50 mL). A dilute sulfuric acid solution prepared by dissolving sulfuric acid (2 mL) in water (9 mL) was added dropwise to the reaction system under cooling conditions in an ice bath. After the dropwise addition, the reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the acetone was removed by distillation under reduced pressure. The residue was dissolved in ethyl acetate, washed three times sequentially with water and dried with anhydrous magnesium sulfate. The organic solvent was removed by concentration under reduced pressure, and the resulting crude product was recrystallized with a solvent mixture of ethanol-water to give the target product 4-bromo-1-naphthalenecarboxylic acid. The product was a light brown crystal with a yield of 1.272 g, 84% yield, melting point 223-224 °C. 1H-NMR (CDCl3-DMSO-d6, 200 MHz) δ 7.60-7.69 (2H, m), 7.83 (1H, d, J = 7.8 Hz), 8.06 (1H, d, J = 8.2 Hz), 8.28-8.36 (1H , m), 8.99-9.08 (1H, m).IR (KBr, cm-1) 3100-2500, 1694, 1566, 1508, 1279, 1252, 1190, 903, 785, 762.Elemental analysis (C11H7BrO2) Calculated values: C, 52.62; H, 2.81.Measured values: C, 52.42; H, 2.87. H, 2.87.
