The identification of novel succinate dehydrogenase (SDH) inhibitors represents one of the most attractive directions in the field of fungicide research and development. During our continuous efforts to pursue inhibitors belonging to this class, some structurally novel pyrazole-furan carboxamide and pyrazole-pyrrole carboxamide derivatives have been discovered via the introduction of scaffold hopping and bioisosterism to compound 1, a remarkably potent lead obtained by pharmacophore-based virtual screening. As a result of the evaluation against three destructive fungi, including Sclerotinia sclerotiorum, Rhizoctonia solani, and Pyricularia grisea, a majority of them displayed potent fungicidal activities. In particular, compounds 12I-i, 12III-f, and 12III-o exhibited excellent fungicidal activity against S. sclerotiorum and R. solani comparable to that of commercial SDHI thifluzamide and 1.Keywords: fungicidal activity; molecular docking; scaffold hopping; succinate dehydrogenase inhibitors; synthesis;

Succinate dehydrogenase (SDH) has been demonstrated as a promising target for fungicide discovery. Crystal structure data have indicated that the carboxyl “core” of current SDH inhibitors contributed largely to their binding affinity. Thus, identifying novel carboxyl “core” SDH inhibitors would remarkably improve the biological potency of current SDHI fungicides. Herein, we report the discovery and optimization of novel carboxyl scaffold SDH inhibitor via the integration of in silico library design and a highly specific amide feature-based pharmacophore model. To our delight, a promising SDH inhibitor, A16c (IC50 = 1.07 μM), with a novel pyrazol-benzoic scaffold was identified, which displayed excellent activity against Rhizoctonia solani (EC50 = 11.0 μM) and improved potency against Sclerotinia sclerotiorum (EC50 = 5.5 μM) and Phyricularia grisea (EC50 = 12.0 μM) in comparison with the positive control thifluzamide, with EC50 values of 0.09, 33.2, and 33.4 μM, respectively. The results showed that our virtual screening strategy could serve as a powerful tool to accelerate the discovery of novel SDH inhibitors.Keywords: amide feature-based pharmacophore model; hit-to-lead optimization; in silico library; molecular modeling; succinate dehydrogenase inhibitors;

An integrated virtual screening protocol by combining molecular docking and pharmacophore mapping was established to identify novel inhibitors of JAK2 from a commercial compound database. Twelve novel and structurally diverse hits were selected and subjected to in vitro biological tests, and three compounds (A5, A6 and A9) with remarkable JAK2 inhibitory activity were identified. Then, the obtained structures were further used as the template for a subsequent similarity search, leading to the identification of another two promising compounds (B2 and B4). Selectivity profiles of JAK subtype and in vitro anti-cancer activity of the promising compounds were studied, revealing the promising compound B2 was of interest for further study because of its JAK2 selective profile, novelty of skeleton and significantly anti-proliferative effect against cancer cells. Finally, binding patterns of the compounds A5 and B2 were explored to provide a deeper insight for further structural optimization.

A series of 4-phenyl-acyl-substituted 3-(2,5-dimethylphenyl)-4-hydroxy-1-azaspiro[4.5]dec-3-ene-2,8-dione derivatives were designed and synthesized, and their structures were characterized using 1H NMR (or 13C NMR), mass spectrometry, and elemental analysis. The bioactivities of the new compounds were evaluated. These compounds exhibited good inhibition activities against bean aphids (Aphis fabae) and carmine spider mite (Tetranychus cinnabarinus), and 4-phenyl acyl esters showed stronger bioactivity than 4-arylesterases and alkyl esters. The results showed that compound 8-I-e, which contains a para-methoxy group on the phenyl acyl, and compound 8-I-m, which contains a para-trifluoromethyl group on the phenyl acyl, displayed potent insecticidal activity against A. fabae and T. cinnabarinus respectively. The insecticidal activity showed a clear structure–activity relationship, confirming the importance of the flexible bridge. The DFT/B3LYP/6-31(d) level method was used to calculate molecular geometries and electronic descriptors. These factors included total energy, charge distribution, and the linear orbital level of the title compounds. Quantitative structure–activity relationship studies were performed on these compounds using quantum-chemical and physicochemical parameters as independent variables and insecticidal activity as a dependent variable. Insecticidal activity was most closely correlated (r > 0.8) with quantum chemical and physicochemical parameters.