A general method is described for the preparation of N-unsubstituted azetidinones. The imine derived from p-anisidine and cinnamaldehyde is annelated with azidoacetic trifluoroacetic anhydride to yield the azetidinone 9. Treatment of 9 with ceric ammonium nitrate (CAN) yields the N-dearylated product 3. Similarly, treatment of the imine derived from p-anisidine and methyl glyoxylate methyl hemiacetal with N-phthalimidoacetyl chloride yields azetidinone 13. Derivatives of 13 at C-3 and C-4 when treated with 17, 19, and 21. Acylated derivatives of 3-aminomonobactamic acid (1) + 3 are efficacious antimicrobial agents for a variety of grampositive and negative bacteria.1 2345In particular, compound 2 (SQ 26 776) possesses a broad spectrum of gram-negative

Aus den Iminen (V) und (VIII) des p‐Anisidins werden die N‐Aryl‐azetidinone (I) auf den im Formelschema angegebenen Wegen hergestellt.