Synthesis Of 4-acetoxyazetidin-2-one

4-acetoxyazetidin-2-one(4AA)is a kind of important medicinal intermediate, mainly employed to synthesizeβ-Lactam antibiotics like carbapenems and penems.In this paper, 3-(1-(tert-butyldimethylsilyloxy)-ethyl)-4-(trimethylsilyloxy) azeti- din-2-one was synthesized using enol silicon ether as raw material, through cycloadd- ition, cleavage of chlorine-sulonly and hydrolysis processes. The optimal reaction conditions of cycloaddition was as the following: The molar ratio of enol silicon ether to chlorosulfonyl isocyanate(CSI) was 1: 1. Dichloromethane was the solvent. Reaction temperature was -40~-30℃. Reaction time was 2h. The optimal reaction conditions of cleavage of chloro-Sulfonyl was as the following: The molar ratio of vitride solution to CSI was 1.1:1. The reation temparature was -40~-30℃. Reation time was 2h. Then the liquid was hydrolyzed with NaOH and later under stirring 15 minutes at room temperature. The product was recrystallized with hexane. The yield was 50%. And the purity reached 89.4%. The melting point was 95~98℃.The acylation process to synthesize 4AA using 3-(1-(tert-butyldimethylsilyloxy)- ethyl)-4-(trimethylsilyloxy)azetidin-2-one as raw material, (AcO)2O as acylating agent, pyridine as solvent and 4-methylbenzenesulfonic acid as catalyst has been carried out in this paper. This reaction proceeded 45 hours at 0℃. Later the product was recrystallized with hexane. Then white needless crystal 4AA was abtained with yield of 93%. And the purity reached 99.2%. The melting point was 107~109℃.With the advantages of short route, simple process and low cost, the process has industrial application potential.