The treatment of dl-threo-1-phenyl-1-benzoyloxy-2-amino-3-bromopropane (I) hydrobromide in basic media yielded dl-1-phenyl-2-benzoylaminoprop-1-en-3-ol (or dl-1-phenyl-2-benzoyliminopropan-3-ol) (IV) via dl-threo-2-phenyl-4-phenylhydroxymethyl-⊿2-oxazoline (II). dl-threo-1-Phenyl-2-benzoylaminopropane-1, 3-diol (III) was also formed by treatment of hydrobromide of (I) with potassium acetate and hydrous ethanol. These formation mechanisms were discussed on the ground of stereochemical findings.