The synthesis of [1-[(5-hydroxy-4-(phenylmethyl)-3-oxazolidinyl)carbonyl]-2-ethylpropy lcarbamic acid phenylmethyl ester (2; MDL 104,903), a potent inhibitor of calpain, is described. Synthesis of related compounds, which offer insights into the mechanism of action for 2, are also described, as is an O-acetyl prodrug derivative of 2.