反应详情

To a stirred solution of AlBr3 (12.6 g, 47.4 mmole) in benzene (45 mL) is added dropwise under nitrogen a solution of the methylether (5 g, 18.45 mmole) of Step A in benzene (12 mL) over 30 minutes. The resulting solution is stirred at room temperature for 3.5 hours. (TLC, 8:2 hexane-ethyl acetate). The mixture is cooled in an ice bath and the complex is decomposed by the dropwise addition of 6N-HCl (ca. 37 mL). The organic layer is separated and the aqueous phase is reextracted with ether (3×). The combined extracts are concentrated to a small volume and extracted again with 2.5N-NaOH (2×50 mL +1×10 mL). The basic extracts are cooled and acidified with concentrated HCl (to pH 2). The solid is collected and dried (4.27 g, 90%). It is used in the next step without further purification.

1. temperatureThe mixture is cooled in an ice bath
2. customThe organic layer is separated
3. concentrationThe combined extracts are concentrated to a small volume
4. extractionextracted again with 2.5N-NaOH (2×50 mL +1×10 mL)
5. temperatureThe basic extracts are cooled
6. customThe solid is collected
7. customdried (4.27 g, 90%)
8. customIt is used in the next step without further purification