Syntheses and biological activities of new carbapenem derivatives

3-beta-Alanyloxymethyl, 3-glycyloxymethyl and 3-methyl derivatives of 6-(1-hydroxyethyl)-carbapenems, (VIIa, VIIb and VIII), and 3-methyl-6-(1-hydroxyethyl)carbapenam (IX) were synthesized from 3-(1-tert-butyldimethylsilyloxyethyl)-4-(3-chloro-2-oxopropyl) -2-azetidinone (I). The antibacterial activities of these compounds proved that the delta 2 double bond was essential for the appearance of bioactivity, whereas the amino group on the C-3 side chain was not necessary.