Water → n-Cbz-3-hydroxypiperidine

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Reaction Steps

To a 1-liter 3-necked round bottom flask, equipped with mechanical stirrer and two addition funnels, is added 30 g (0.2966 mole) of 3-hydroxypiperidine and 300 ml of water. The resulting solution is stirred and is cooled to ~0° C. with ice-salt bath. At this point the benzyl chloroformate (51 ml, 0.356 mole) is added dropwise from one funnel and the 2N NaOH (178 ml) from the other funnel (at a slightly faster rate) during which time the temp. is maintained at ~0° C. After addition is complete, the mixture is stirred in the cold for 2 hr, then overnight at ambient temp. After this time an oily residue separates from the reaction solution. Ethyl acetate is added (250 ml) to the reaction and is stirred for 1/2 hr. The phases are separated and the aqueous phase is extracted once more with EtOAc (250 ml). All organic phases are combined, washed with 1×150 ml saturated NaHCO3, 1×150 ml H2O, 1×150 ml 10% HCl, 1×150 ml H2O and dried overMgSO4. The mixture is filtered and concentrated on a roto-evap under reduced pressure, to yield a viscous oil, which is stored under vacuum to remove any residual solvents as, 3-Hydroxy-1-piperidinecarboxylic Acid, Phenylmethyl Ester, a clear oil.

Provenance & Evidence