Synthesis of 4-Substituted Monocyclic β-Lactams by a Lewis Acid-mediated Reaction

抄録

The synthesis of 4-substituted monocyclic β-lactam is described. The key step in this method was accomplished by nucleophilic replacement in the presence of Lewis acid, that is, (3S, 4S)-4-acetoxy-3-phenylacetamido-2-azetidinone derivatives or oxazolinoazetidinone derivatives were reacted with nucleophiles (5-mercapto-l-methyltetrazole, 5-methyltetrazole, l-ethyl-2, 3-dioxopiperazine, l-ethyl-4-trimethylsilyl-2, 3-dioxopiperazine) in the presence of Lewis acids (BF₃•Et₂O, SnCl₄, TiCl₄, ZnCl₂) to afford the title compounds. The antibacterial activities of the compounds thus obtained were compared with those of the reference compound (pyridium (3S)-3-phenylacetamido-2-azetidinone-1-sulfonate).