1. 6-Hydroxy-2-naphthalenecarboxylic acid (5.29 g, 28.0 mmol) was dissolved in ethanol (50 mL) at 0 °C, and thionyl chloride (6 mL) was added slowly. 2. The reaction mixture was stirred at room temperature for 72 h. 3. Upon completion of the reaction, the excess reagent was removed by rotary evaporation. 4. The residue was dissolved in ethyl acetate (100 mL), and washed with water (80 mL), cold 1M sodium bicarbonate solution (80 mL) and brine (80 mL). 5. （The residue was dissolved in ethyl acetate (100 mL) and washed sequentially with water (80 mL), cold 1 M sodium bicarbonate solution (80 mL) and brine (80 mL). 5. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated to give ethyl 6-hydroxy-2-naphthoate in 99% yield. 6. The product was characterized by 1H NMR (CDCl3) and LCMS (APCl): 1H NMR (CDCl3): δ 8.53 (1H, br s), 8.5 (1H, br s), 8.3 (1H, br s), 8.4 (1H, br s). , br s), 8.01 (1H, dd, J = 8.5,1.7 Hz), 7.86 (1H, d, J = 8.5 Hz), 7.20-7.13 (2H, m), 4.43 (2H, q, J = 7.3 Hz), 1.43 (3H, t, J = 7.1 Hz). lcmS (apcl): 217.1 (m + h + ).
