L-threonine-@-lactone (21) was transformed to a series of N-acylated derivatives including the following: 22d (2, 3-dihydroxybenzoyl), 26 (2-hydroxybenzoyl), 27 (3, 4- dihydroxybenzoyl), 29 (4'-methyl-2, 2'-bipyridine-4-carbonyl), 31 (c-(ba-aminoadipoyl)), 34 ((N'-2, 3-dihydroxybenzoyl)-@-alanyl), 36 (bromoacetyl), 36 ((6-purinylthio) acetyl), and 37 ((4-pyridy1thio) acetyl). The results show that a-amino@-lactones bearing an N-acyl group ...