反应详情

Glacial HOAc (120 ml) was added to a suspension of the product of step 8 (32.4 g, approx. 103 mmol) in 210 ml of 30-32% anhydrous HBr in glacial HOAc (approx. 1.03 mol) to complete the dissolution. The resulting solution was stirred at 70° C. for 6h and at 50° overnight. The reaction mixture was then cooled to r.t., diluted with H2O (750 mL) and extracted with CH2Cl2 (7×). The combined organic extracts were concentrated in vacuo. The residue was diluted with toluene (500 mL) and concentrated in vacuo 5 times to remove HOAc. The residue was dissolved in 1M aq KOH (750 mL), washed with CH2Cl2 (4×), acidified to pH 1 with concentrated HCl and extracted with CH2Cl2 (6×). The combined organic extracts were dried over Na2SO4 and concentrated in vacuo to afford 17.6 g of the title compound as a pale yellow liquid which was used as such for the next step.

1. dissolutionthe dissolution
2. extractionextracted with CH2Cl2 (7×)
3. concentrationThe combined organic extracts were concentrated in vacuo
4. additionThe residue was diluted with toluene (500 mL)
5. concentrationconcentrated in vacuo 5 times
6. customto remove HOAc
7. dissolutionThe residue was dissolved in 1M aq KOH (750 mL)
8. washwashed with CH2Cl2 (4×)
9. extractionextracted with CH2Cl2 (6×)
10. dry with materialThe combined organic extracts were dried over Na2SO4
11. concentrationconcentrated in vacuo