6alpha-substituted penicillins.
D008738:Methyl Ethers / Q000138:chemical synthesis; D009570:Nitriles / Q000138:chemical synthesis; D010406:Penicillins / Q000138:chemical synthesis*; D010647:Phenyl Ethers / Q000138:chemical synthesis
D008738:Methyl Ethers; D009570:Nitriles; D010406:Penicillins; D010647:Phenyl Ethers