Hydrochloric Acid → L-Leucine ethyl ester

Participants

Reaction Conditions

Reaction Steps

2.14 g (6.77 mmoles) of compound (I) are dissolved in anhydrous toluene (34 ml) and pyridine (0.75 ml). The reaction is cooled to a temperature of 10° C. and, under vigorous stirring, a solution of oxalyl chloride (0.728 ml) in toluene (2 ml) is added. The reaction is maintained under stirring at a temperature of 10° C. for 1 hour. Then a suspension of L-leucine ethyl ester hydrochloride (6.6 g, 33.8 mmoles) in toluene (6 ml) and pyridine (2.71 ml) is added. The reaction is heated at a temperature of 40° C. for 4 hours, with vigorous stirring. After that ice (40 g) is added and the reaction pH is adjusted to 2 con 1N HCl, the organic phase is separated and the aqueous phase is extracted with dichloromethane (3×50 ml). The combined organic phases are then dried over sodium sulfate and evaporated under vacuum to give a crude, which is subsequently purified by silica gel chromatography (dichloromethane/methanol 9/1) 2.03 g (4.44 mmoles) of compound (II) are obtained, wherein Y=--CH(Q)--T is the residue of L-leucine ethyl ester, (66% yield).

Provenance & Evidence