Diisobutylaluminum hydride → Diisopropyl Ether

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Reaction Steps

In a 100 ml three-necked flask under argon, reflux a suspension of 1 g of methyl ester of 9(R,S)-[(1H-pyrrolo[2,3-b]pyridine-4-carbonyl)amino]-9H-fluorene-4-carboxylic acid, obtained in the previous stage, in 50 ml of anhydrous tetrahydrofuran, and then add, dropwise, 7.825 ml of a 20% solution of diisopropylaluminium hydride (DIBAL-H) in toluene. After stirring for 15 minutes at reflux, add a further 2.6 ml of the above solution of DIBAL-H and maintain the reflux for a further 15 minutes. After cooling to room temperature, the reaction medium is run, dropwise, into 25 ml of a saturated aqueous solution of ammonium chloride, and then extracted 3 times with 25 ml of ethyl acetate. The combined organic phases are dried over magnesium sulphate and concentrated to dryness under reduced pressure. After purification by flash chromatography on silica gel (40-63 μm), eluting with a mixture of dichloromethane and methanol (97.5/2.5 by volume), and then formation of a paste with diisopropyl ether, in this way we obtain 200 mg of 9(R,S)-[(1H-pyrrolo[2,3-b]pyridine-4-carbonyl)amino]-9H -fluorene-4-methanol, in the form of a beige solid, which is used, with the following characteristics:

Provenance & Evidence