Study of the Alkaline Hydrolysis of the Azetidin‐2‐one Ring by ab initio Methods: Influence of the solvent

摘要: A comprehensive study of the alkaline hydrolysis b-lactam ring azetidin-2-one was carried out using ab tnitio molecular-orbital calculations at RHF/6-31 + G* level. The influence solvent on this reaction investigated by field method (SCRF); found to suppress interference some gas-phase reactions and allow presence a transition state be detected as nucleophile approaches ring. corresponds structure where OH- group lies distance 1.927 8, from C=O p-lactam exhibits potential barrier 13.6 kcal/mol. Introduction. - Since their discovery in 1920s, antibiotics have played prominent role fight against bacterial diseases. early theoretical studies Boyd (l), who related various structural parameters chemical reactivity antibacterial action, been followed much research reactivity. Such has substantially expanded available knowledge mechanisms action antibiotics, which turn facilitated determination new structures with similar besides resistance defense mechanisms. Ab initio were recently used determine for p-lactams (2-71. On other hand, (basically hydrolysis) /3-lactam studied preferentially semi-empiri- cal methods (8-121, exception investigations Petrongolo et al. (13) It should noted that most such gas phase thus subject interferences substitution elimination (9) (15) Neither quality basis sets nor analysis process reported date. This paper presents To elucidate solvent, also performed reaction-field method, allows considered continuum given dielectric constant surrounds molecule. All based 6-31 set including polarized diffuse function heavy atoms. ~41.