Antibiotics U 1200Synthesis and in vitro Activity of Novel 1β-Methylcarbapenems Having Spiro[2,4]heptane Moieties. Part 2. -Most of the new carbapenems (IV) (7 examples) display an antibacterial activity which is similar or superior to the standard imipenem. In particular, excellent effects are observed for compound (IVa). -(PARK, H. B.; JUNG, M. H.; CHO, J.-H.; OH*, C.-H.; Bull. Korean Chem.