Studies on .beta.-lactam antibiotics. III. Synthesis of 2-methyl-3-cephem derivatives

Natural Occurrence, Syntheses, and Applications of Cyclopropyl-Group-Containing α-Amino Acids. 1. 1-Aminocyclopropanecarboxylic Acid and Other 2,3-Methanoamino Acids

“…505,506 Such compounds were further converted by cyclopropane-ring opening reactions into the corresponding cephem derivatives. 507 The Z-protected p-nitrobenzyl ester 571 has been transformed into the (5S)-5-amino-5-carboxypentanoyl-substituted derivative 573 (Figure 12), which was found to be a potent reversible inhibitor of the ring-expansion of penicillin N induced by deacetoxycephalosporin C syn- thetase, but not a substrate of this enzyme. 508 In this context, the reduction of several 2,3-methylenepenam sulfoxides to the corresponding sulfides has been examined extensively.…”

“…Among these compounds were penams, analogues of penicillin, bearing a fused cyclopropane moiety, leading to tricylic β-lactams. Thus, the tricyclic 2,3-methylenepenams 568 − 571 (Figure ) were synthesized in such a way that the cyclopropane ring was built up by an intramolecular S N 2 reaction. , Such compounds were further converted by cyclopropane-ring opening reactions into the corresponding cephem derivatives . The Z -protected p -nitrobenzyl ester 571 has been transformed into the (5 S )-5-amino-5-carboxypentanoyl-substituted derivative 573 (Figure ), which was found to be a potent reversible inhibitor of the ring-expansion of penicillin N induced by deacetoxycephalosporin C synthetase, but not a substrate of this enzyme .…”