25804-49-3

75-65-0

99-96-7

25804-49-3

Using p-hydroxybenzoic acid (1.50 g, 10.86 mmol) and tert-butanol (13.34 g, 18 mmol) as raw materials, DCC (2.5 g, 12.00 mmol) was dissolved in DCM (40 mL) catalyzed by DBU (0.19 mL, 1.20 mmol), and the reaction mixture was stirred vigorously for 18 hours at room temperature. After completion of the reaction, the solvent was evaporated to dryness and the residue was dissolved in DCM (50 mL) and filtered to remove insoluble material. The filtrate was washed sequentially with saturated NaHCO3 solution (50 mL), K2CO3 solution (2 x 50 mL) and saturated NaCl solution (50 mL). The organic phase was dried with MgSO4, filtered and the solvent was evaporated to give the crude product. The crude product was purified by column chromatography (EtOAc:hexane gradient elution) to afford tert-butyl 4-hydroxybenzoate (SO2-059) (31) as a white crystalline solid (1.1 g, 55% yield).1H NMR (400 MHz, CDCl3) δ 7.89 (d, J = 8.8 Hz, 1H), 6.84 (d, J = 8.9 Hz, 1H) 5.29 (s, 1H), 1.57 (s, 9H).