Synthesis, Structure Elucidation and Reactivity of Novel Azetidinone-oxiranes

Sa？etak Oxidation of 2,3-cis-2-sulfonamide-N-butenoate-azetidinone 3 and 2,3-trans-2-acetoxy-N-butenoate-azetidinone 6 led to the formation of azetidinone-oxiranes 5 and 7. Molecular structure of 5, including its absolute configuration, was unambiguously determined by X-ray structure analysis. Cleavage of the benzyl ester group using AlCl3 / anisole as well as H2Pd/C procedures failed. Instead, new methods for the removal of the substituent from the azetidinone nitrogen of compounds 5 and 7 were found. Azetidinone 8 was isolated in the reaction of azetidinone-oxiranes 5 with AlCl3/anisole. During hydrogenation of azetidinone-oxirane 5, afforded azetidinone p-hydroxy acid sodium salt 9, which was transformed into azetidinone 8 in acidic media. Compounds 5 and 7 gave the azetidinone-halohydrines 10 and 11 by the oxirane ring opening with HCl