反应详情

Sodiumcyanoborohydride (1.3 g, 20.7 mmol) was added during 10 min. to a stirred solution of (R)-8-fluoro-5-methoxy-3-(N-3-pentylamino)chroman (3.69 g, 13.8 mmol) and propionaldehyde (5 ml, 69.3 mmol) in 100 ml dry MeOH. The pH was adjusted with acetic acid to pH 6. The solution was stirred in room temp. for 18 hours and propionaldehyde (1 ml, 13.7 mmol) was added. After stirring at room temp. for 3.5 hours the solution was concentrated, and the residue was partitionated between 100 ml 2MNH3 and 200 ml ether. Extraction with 2×200 ml ether and drying of the combined organic layers (Na2SO4) gave after evaporation a crude product. Purification by flash chromatography on silica with hexane:acetone 20:1 gave 4.03 g of (R)-8-fluoro-5-methoxy-3-(N-3-pentyl-N-n-propylamino)chroman as an uncolored oil. [α]D22 -83° (c 1.08 in MeOH).

1. stirringAfter stirring at room temp. for 3.5 hours the solution
2. concentrationwas concentrated
3. extractionExtraction with 2×200 ml ether
4. dry with materialdrying of the combined organic layers (Na2SO4)
5. customgave
6. customafter evaporation a crude product
7. customPurification by flash chromatography on silica with hexane:acetone 20:1