Convenient Synthesis of Bis(oxazoline) Dicarboxylate Derivatives

The synthesis of bis(oxazoline) dicarboxylate derivatives was investigated.Diethyl-aminosulfur trifluoride(DAST)was used as a convenient cyclization reagent in the synthesis of bis(oxazoline)dicarboxylate derivatives,which can not be obtained by the general method using MsCl and Et3N as dehydrating cyclization reagent.