Hydrochloric Acid → 1-(tert-butoxycarbonyl)-4-(cyclopropylmethyl)piperidine-4-carboxylic acid

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Reaction Steps

Potassium hydroxide powder (85% assay, 2.16 gm, 0.0327 mol) and 18-crown-6 ether (350 mg) are added to a solution of 4-cyclopropylmethylpiperidine-1,4-dicarboxylic acid-1-tertbutyl ester-4-ethyl ester (1.2 gm, 0.0039 mol) in dry toluene (15 mL). The reaction mixture is refluxed for 30 minutes. It is then treated with demineralized water (15 mL) at room temperature and pH is adjusted to ˜3-4 using 2N HCl (20 mL). The aqueous layer is extracted with ethyl acetate (2×15 mL) and the combined extract is dried over sodium sulfate. Removal of solvent gives 4-cyclopropylmethylpiperidine-1,4-dicarboxylic acid monotertbutyl ester.

Provenance & Evidence