Abstract
Esters of several carbobenzoxyamino acids with 4-hydroxymorpholine were prepared by direct condensation using dicyclohexylcarbodiimide (Table I). The esters obtained were crystalline solid and reacted readily with amino acid ester hydrochlorides in the presence of sodium acetate (or triethylamine with acetic acid) to form the corresponding carbobenzoxydipeptide esters (Table II). Presence of racemate (ca.0.6%) was observed by Anderson's test.
