Methanol → 9-Cis-Retinoic Acid

Beteiligte Stoffe

Reaktionsschritte

A mixture was formed of 2.42 g (27.89 mmol) of MnO2, 0.35 g (7.2 mmol) of NaCN, 0.12 ml (2.1 mmol) glacial acetic acid in 20 ml of CH3OH at 0° C. A separate solution was formed of 600 mg (2.1 mmol) of 9-cis-retinal (I) in 9 ml of CH3OH, also at 0° C. The solution of 9-cis-retinal was added dropwise to the mixture and stirred for 2.5 h at constant temperature and the reaction mixture was filtered through Celite. The filter cake was washed with a 1:1 mixture of CH3OH and water. The filtrates were combined and diluted with additional water and then extracted three times with ether. The combined organic extracts were dried over MgSO4 and concentrated under reduced pressure. Purification by silica gel flash column chromatography using 20:1 hexane:ethyl acetate as eluent gave the pure methyl ester of 9-cis-retinoic acid (II) in the amount of 530 mg, a yield of 80%. The structure was confirmed by NMR. ##STR9##

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