“…Therefore, the study of approaches to the synthesis of phosphorylated peptidomimetics is of undoubted interest. It was previously shown that the 5-amino-1,3-oxazole derivatives containing the diethoxyphosphoryl group in position 4 are cleaved by water in the presence of various acidic agents such as acetic acid, 17,19 trifluoroacetic acid, 18,19 hydrochloric acid 34,35 and p-toluenesulfonic acid. 16 Also recently, we found that when diethyl ester (5-(2-hydroxyethyl)-N-methylamino)-2-phenyl-1,3-oxazol-4-ylphosphonic acid reacts with hydrogen chloride under anhydrous conditions, a phosphopeptidomimetic containing 2-chloroethyl fragment 18 is formed.…”