Реакция #80564

Уравнение реакции

NaCNBH3

HOAc

cyclobutanone

(R)-3-(N-cyclopentylamino)-8-fluoro-5- methoxy-3,4-dihydro-2H-1-benzopyran

→

title compound

Выход 53.0%

(R)-3-(N-Cyclopentyl-N-cyclobutyl-amino)-8-fluoro-5-methoxy-3,4-dihydro-2H-1-benzopyran

Выход 53.0%

Растворители

methanol

Условия реакции

Обработка

1. 1
   workup.ADDITIONadded in portions at room temperature
2. 2
   workup.ADDITIONwas added
3. 3
   ДругоеThe solvent was evaporated
4. 4
   Экстракцияthe residue worked up by extraction

Методика

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%).

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