Hydrochloric Acid → N-(BOC-aminoethyl)epsilon-(2-chlorobenzyloxycarbonyl)-lysine allyl ester

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Reaction Conditions

Reaction Steps

ε-(2-chlorobenzyloxycarbonyl)-lysine allyl ester (from example 18) was dissolved in methanol (50 mL) and cooled to 0° C. To the resulting solution was added sodium cyanoborohydride (5.9 mmol) followed by acetic acid (0.75 mL). After 5 minutes BOC-amino-acetaldehyde (13.3 mmol) was added and the reaction mixture was stirred for an additional 1 h. The methanol was removed in vacuo and the oil was dissolved in ethyl acetate (40 mL), washed with saturated aqueous NaHCO3, brine, dried over Na2SO4 and concentrated to give a clear colorless oil. This oil was dissolved in dry ether (80 mL), cooled to −20° C., and a molar equivalent of HCl in ether was added slowly. The resulting white solid was collected by filtration and air dried. Precipitation of the air-dried white solid from dry ether gave analytically pure title compound.

Provenance & Evidence