The Synthesis Of Penem Antibiotics

The structure of penem is similar to the combination of the thiazolidine ring in penicillin a- nd the dihydrothiazine ring in cephalosporins. Penem show broad-spectrum antibacterial activity against both aerobic and anaerobic Gram-positive and Gram-negative bacteria and it is absorbed easily. An important property of penem is their resistance to the actions ofβ-lactamases and DHP -Ⅰ.Mulriple structures and new penem antibiotics are required exigently because of the inferior stability and low activity against Pseudomonas aeruginosa. We designed and synthesized a series of penems with 2-phenyl and 2-phenylethylene.Our research was focused on the synthesis of new penem compounds. Displacement of the acetoxy group of the optical activity material (3R,4R)-3-[(1R)-tert-butyldimethylsilyloxyethyl]- 4-acetoxy-2-azetidinone (4AA) with the thionocarboxylic acids, acylation to provide the oxalam- ide, followed by triethylphosphite-induced cyclization to afford the target compounds. 7 compo- unds and intermediates were synthesized, of which 5 compounds were previously unreported. All the compounds were verified by MS, NMR and other methods.