Antibacterial activity is exhibited by 2-azetidinones having a 3-acylamino substituent and having an activating group in the 1-position of the formula ##STR1## wherein R is ##STR2## A.sub.1 is --NH-- or ##STR3## A.sub.2 is ##STR4## or --CH.dbd.CH--.
2-氮杂环丁酮具有3-酰
氨基取代基,并且在上述式子的1-位置带有活化基团,表现出抗菌活性。其中R为A1为--NH--或A2为或--CH.dbd.CH--。