6-methyl penicillins and 7-methyl cephalosporins.
D002511:Cephalosporins / Q000138:chemical synthesis*; D008722:Methods; D008745:Methylation; D010406:Penicillins / Q000138:chemical synthesis*; D011480:Protease Inhibitors
D002511:Cephalosporins; D010406:Penicillins; D011480:Protease Inhibitors