L-Threonine Benzyl Ester Hydrochloride

[1] Charles M, et al. Serine and Threonine Schiff Base Esters React with β-Anomeric Peracetates in the Presence of BF3·Et2O to Produce β-Glycosides. Journal of Carbohydrate Chemistry, 2010; 29.

L-threonine benzyl ester hydrochloride salt was reacted with the diaryl ketimine bis-(4-methoxyphenyl)-methenamine in CH3CN at rt to form the more nucleophilic L-threonine Schiff base (Benzyl N-bis (4-methoxyphenyl)methylene-L-threoninate) in excellent yield. In addition, L-threonine Schiff base, acting as glycosyl acceptor, reacted at rt with simple sugar peracetate donor with BF3·OEt2 promotion to provide the corresponding L-threonine O-linked glycosides in excellent yields and purities[1].

The benzyl ester hydrochloride salt, L-Threonine Benzyl Ester Hydrochloride, was  prepared from L-threonine and PhCH2OH in the presence of p-toluenesulfonic acid[1]. Specifically, L-Threonine (4.0 g, 34 mmol) and pTsOH acid monohydrate (7.10 g, 38 mmol) were reacted with benzyl alcohol (40 mL) in 50 mL dry benzene using a Dean-Stark apparatus according to the procedure of Petursson and Bald-win. Yield:71.3%