Glycolic Acid → 4-(5-Hydroxymethyl-[1,2,4]oxadiazol-3-yl)-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of hydroxy-acetic acid (1.67 g, 22 mmol), NEt3 (4.4 g, 44 mmol) in toluene (150 mL) was added isobutylchloroformate (6 g, 44 mmol) at 0° C. The mixture was stirred at room temperature for 1.5 hours. 4-(N-Hydroxycarbamimidoyl)-piperidine-1-carboxylic acid tert-butyl ester (5.35 g, 22 mmol) was added to the mixture. The mixture was heated under reflux overnight, and then cooled to room temperature; the mixture was washed successively with H2O and brine. After drying (Na2SO4), the solvent was removed. The residue was dissolved in THF (20 mL), and aqueous NaOH (10 mL, 10 mmol) was added. The mixture was stirred at room temperature for 2 hours and diluted with EtOAc (50 mL). The organic layer was washed with brine, after drying (Na2SO4), the solvent was removed in vacuo, and the residue was purified by silica column chromatography with EtOAc/hexanes to afford the desired product.

Provenance & Evidence