204377-88-8

1403387-58-5

204377-88-8

Step 3: Synthesis of 8-bromo-benzotetrahydropyran-4-one (P34c) Compound P34b (2.0 g, 8.15 mmol) was dissolved in ethylene glycol (20 mL) and heated to reflux for 4 hours. After completion of the reaction, the reaction mixture was cooled, poured into water and extracted twice with ether (Et2O). The organic layers were combined and washed sequentially with 1 M aqueous sodium hydroxide (NaOH) and saturated aqueous ammonium bicarbonate (NH4HCO3). The organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated, and finally purified by column chromatography (eluent: petroleum ether/ethyl acetate = 50/1) to afford the target compound P34c (0.88 g, 48% yield) as a yellow solid.