反应详情

To a solution of (R)-3-(N-cyclopentylamino)-8-fluoro-5-methoxy-3,4-dihydro-2H-1-benzopyran (0.9 g, 3.4 mmol), HOAc (0.22 g, 3.6 mmol) and cyclobutanone (2g, 30 mmol) in methanol (25 mL), were NaCNBH3 (1 g, 16 mmol) added in portions at room temperature. After stirring for four days GC indicated 37% product. pH was adjusted to 5 (HOAc) and additional (1 g, 15 mmol) cyclobutanone was added. After stirring for further 6 days, GC indicated 64% conversion. The solvent was evaporated and the residue worked up by extraction. Flash chromatography (EtOAc/P-ether, 1+1), gave 0.53 g (53% yield) of the title compound as a colourless oil. GC/MS (70 eV) M=319 (3%).

1. additionadded in portions at room temperature
2. additionwas added
3. customThe solvent was evaporated
4. extractionthe residue worked up by extraction