反应详情

温度

-40 °C

(R)-3-(N-Cyclobutyl-N-n-propylamino)-8-fluoro-5-methoxy-3,4-dihydro-2H-1 -benzopyran hydrochloride (1.0 g, 3.03 mmol) was dissolved in anhydrous CH2Cl2 (25 mL) and cooled to -40° C. To the solution was BBr3 (0.72 mL, 7.6 mmol), dissolved in anhydrous CH2Cl2 (4 mL), added dropwise. The cooling-bath was removed and after 2 h at room temperature the reaction was complete. The reaction was poured out onto an ice/2M NH3 solution and the CH2Cl2 portion was separated, the aqueous layer re-extracted, twice, with CH2Cl2. The combined CH2Cl2 portions were dried (MgSO4), filtered, and the solvent removed in vacuo to give the crude residue. Chromatography on silica (eluent: 25% ethyl acetate/hexane followed by 50% ethyl acetate/hexane) gave 0.83 g (98% yield) of the title compound as a gum. [α]21D =-80.5° (C=0.1; CHCl3) GC-MS (70 eV) M=279 (0.2%).

1. additionadded dropwise
2. customThe cooling-bath was removed and after 2 h at room temperature the reaction
3. additionThe reaction was poured out onto an ice/2M NH3 solution
4. customthe CH2Cl2 portion was separated
5. extractionthe aqueous layer re-extracted
6. dry with materialThe combined CH2Cl2 portions were dried (MgSO4)
7. filtrationfiltered
8. customthe solvent removed in vacuo
9. customto give the crude residue