Jungheim L N, Boyd D B, Indelicato J M, Pasini C E, Preston D A, Alborn W E
Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiania 46285.
J Med Chem. 1991 May;34(5):1732-9. doi: 10.1021/jm00109a030.
Bicyclic tetrahydropyridazinones, such as 13, where X are strongly electron-withdrawing groups, were synthesized to investigate their antibacterial activity. These delta-lactams are homologues of bicyclic pyrazolidinones 15, which were the first non-beta-lactam containing compounds reported to bind to penicillin-binding proteins (PBPs). The delta-lactam compounds exhibit poor antibacterial activity despite having reactivity comparable to the gamma-lactams. Molecular modeling based on semiempirical molecular orbital calculations on a Cray X-MP supercomputer, predicted that the reason for the inactivity is steric bulk hindering high affinity of the compounds to PBPs, as well as high conformational flexibility of the tetrahydropyridazinone ring hampering effective alignment of the molecule in the active site. Subsequent PBP binding experiments confirmed that this class of compound does not bind to PBPs.
合成了双环四氢哒嗪酮（如13，其中X为强吸电子基团）以研究其抗菌活性。这些δ-内酰胺是双环吡唑烷酮15的同系物，双环吡唑烷酮15是最早报道的与青霉素结合蛋白（PBPs）结合的不含β-内酰胺的化合物。尽管δ-内酰胺化合物的反应活性与γ-内酰胺相当，但其抗菌活性较差。基于在Cray X-MP超级计算机上进行的半经验分子轨道计算的分子建模预测，其无活性的原因是空间位阻阻碍了化合物与PBPs的高亲和力，以及四氢哒嗪酮环的高构象灵活性妨碍了分子在活性位点的有效排列。随后的PBP结合实验证实这类化合物不与PBPs结合。
