反应详情

To a solution of intermediate (2-a) (0.03 mol) in DCM (50 ml) and Na2CO3 saturated (50 ml), bromine (0.09 mol) was added dropwise and the reaction mixture was stirred for 16 hours at room temperature. Then a Na2SO3-solution (10%) was added and the mixture was stirred for 5 minutes at room temperature and then neutralized with a saturated Na2CO3-solution. The aqueous layer was extracted with DCM and the separated combined organic layers were dried, filtered and the solvent was evaporated. The residue was purified by short open column chromatography over silica gel (eluent: CH2Cl2/(MeOH/NH3 saturated) 95/5). The desired fractions were collected and the solvent was evaporated. The residue was purified by high-performance liquid chromatography over silica gel (eluent: CH2Cl2/(MeOH/NH3 saturated) 97/3). The product fractions were collected and the solvent was evaporated, yielding 2.7 g of (S)-7-bromo-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-methanol (intermediate 41) and 0.26 g of 8-bromo-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-methanol (intermediate 42)

1. stirringthe mixture was stirred for 5 minutes at room temperature
2. extractionThe aqueous layer was extracted with DCM
3. customwere dried
4. filtrationfiltered
5. customthe solvent was evaporated
6. customThe residue was purified by short open column chromatography over silica gel (eluent: CH2Cl2/(MeOH/NH3 saturated) 95/5)
7. customThe desired fractions were collected
8. customthe solvent was evaporated
9. customThe residue was purified by high-performance liquid chromatography over silica gel (eluent: CH2Cl2/(MeOH/NH3 saturated) 97/3)
10. customThe product fractions were collected
11. customthe solvent was evaporated