Bicarbonate Ion → Methyl 4-(7-cyano-3-hydroxymethylheptyl)benzoate

Participants

Reaction Conditions

Reaction Steps

33 ml of a 1 M borane-THF complex solution (33 mmol) are added dropwise to a solution of 5 g (16.48 mmol) of methyl 4-(3-carboxy-7-cyanoheptyl)benzoate from Example 92A in 62 ml of THF at −15° C., and the solution is stirred at this temperature for 2 hours. Then a further 16 ml of 1 M borane-THF complex solution are added dropwise, and stirring is continued for 45 minutes. The reaction mixture is then warmed to 0° C. and stirred at this temperature for 1 hour. After reaction is complete, 100 ml of saturated bicarbonate solution are added to the reaction mixture, and the solvent is concentrated to dryness. The residue is taken up in ethyl acetate and water, and the aqueous phase is extracted with ethyl acetate. The combined organic phases are dried over sodium sulfate and again freed of solvent. The resulting crude product is purified by flash chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate 2:1→1:3→100% ethyl acetate). 2.4 g (93% purity, 47% yield) of a colorless solid are obtained.

Provenance & Evidence