Design,synthesis and bioassay of the emerging photo-responsive fungicides

Precise and spatiotemporal control over the pesticide remains to be a challenge.More efficient controlled release systems(CRSs)have been developed to support the precise delivery of active ingredients.Herein,we incorporated the photoremovable protecting groups(PRPGs)into phenamacril(PHE)and obtained two photo-responsive fungicides of NV-PHE and DEACM-PHE.The 4,5-dimethoxy-o-nitrobenzyl(NV)or 7-diethylaminocoumarin(DEACM)-caged PHE could release the active molecule PHE after irradiation of UV light and blue light,respectively.Optical properties and in-vitro/vivo fungicidal activities of NV-PHE and DEACM-PHE demonstrated the feasibility for light controlled release of PHE.DEACM-PHE could release 98%PHE by illumination of blue light.The irradiated DEACM-PHE could preserve the similar bioactivity of PHE,and significantly improve the in-vitro/vivo fungicidal activities compared to the non-irradiated DEACM-PHE.The optical controlled release of PHE from DEACM-PHE enabled the precise and spatiotemporal delivery of PHE,diversifying the development of CRSs for pesticide,and providing environmentfriendly agricultural applications with high pesticide efficiency.

Synthesis, nematicidal activity and docking study of novel chromone derivatives containing substituted pyrazole

A series of chromone derivatives containing substituted pyrazole were designed and synthesized.Preliminary bioassays showed that most of the synthesized compounds exhibited good nematicidal activity in vivo against Meloidogyne incognita at 10 mg/L. Among the tested compounds, A10 and A11 exhibited 100% inhibition rates. In addition, the molecular docking results indicated that both compound A10 and A11 interacts with amino acid residue Tyr121, Trp279, Tyr70, Trp84 and Phe330 of ACh E via hydrogen bond and p–p stacking. This investigation suggested that the chromone containing substituted pyrazole scaffold could be further optimized to explore novel, high-bioactivity nematicidal leads.

Water bridges are essential to neonicotinoids: Insights from synthesis,bioassay and molecular modelling studies

Water-bridged H-bonds have been observed in many cases of ligand-receptor recognitions. To explore the roles of water bridges in the binding of neonicotinoids with receptors, twenty-four neonicotinoid compounds with nine fragments, including 1 H-1,2,3-triazole, CN, COOMe, CONHNH_2, CONHMe, NO_2,NH_2, NHCOMe and NHCSNH_2 were synthesized and evaluated, of which, compounds with cyano group showed the best activities against Aphis craccivora. Accordingly, the cyano group is the optimal fragment mimicking the water bridge. Two cyano-substituted cis-nitromethylene compounds display good insecticidal activities, whereas the LC_(50) values are lower than those of their corresponding prototypes.Docking study showed that the cyano group acts only as H-bond acceptor, while the water bridge can act as both donor and acceptor. It revealed that the water bridge might be stable in the active site and was not suitable to be replaced by other groups. The findings illustrated that the water bridge is necessary for high insecticidal activities of neonicotinoids, which should be also helpful in better understanding the binding mode of neonicotinoids.

Methyl Group in Isocopalane Derivative Showed an Unusual Negative 1H NMR Chemical Shift

An unusual negative 1H NMR chemical shift of methyl group was discovered in condensation product of isoco-palane diterpenoid with p-toluenesulfonyl hydrazide.2D NMR,computational studies and single-crystal X-ray dif-fraction analysis showed that the C-20 methyl group was shielded.

Computational Investigations about the Effects of Heteromolecular Aggregation on Bioactivities:a Case of Neonicotinoids and Water

Molecular aggregation state of bioactive compounds plays a key role in bio-interactive procedure.Diverse ag-gregation states of bioactive compounds contribute to different biological or chemical properties.Water-bridge,as the simple hetero-molecular aggregation,has been found bridging the binding between many bioactive compounds and their targets through hydrogen bonding network,e.g.in the recognition of neonicotinoids with insect nAChRs.To better understanding the roles of water-bridge on bioactivities of compounds,an approach of hetero-dimeric ag-gregation with water was proposed.Quantitative structure-activity relationship(QSAR)and pharmacophore mod-eling investigations were applied on 19 neonicotinoids,as well as their aggregates with water.The aggregate-based CoMSIA,PHASE and linear QSAR models presented better statistical significance and predictabilities than the monomer ones,which indicated that the bioactivities correlated with the aggregate properties and water bridged hy-drogen bond of the active site.All results revealed the essential roles of water-bridge in ligand recognition,which should be considered in future ligand design and optimization.