Sodium Bicarbonate → Benzyl L-leucinate

Participants

Reaction Steps

A solution Of L-leucine benzyl ester tosylate (5.8 g, 14.8 mmol) in 80 mL methylene chloride was stirred together with aqueous solution of saturated sodium bicarbonate (large excess) for I5 min at room temperature. The organic phase was separated, dried over magnesium sulfate and charged with 9-fluorenemethoxycarbonyl-O-succinimide (2.5 g, 7.4 mmol) at room temperature. The reaction was monitored via TLC (silica, 25% EtOAc in hexane). After two hours the reaction was over (according to its TLC with 25% EtOAc in hexane). However it was further stirred at room temperature for 48 hours. The solution was diluted with EtOAc then was washed with water (×2), 3% aqueous HCl, water (×3) and brine. The solution was dried over magnesium sulfate and evaporated. The resulting oil was crystallized from hexane:ether to yield 2.2 g (48.7%) of colorless solid, mp 91°-2° C.

Provenance & Evidence