Design, synthesis and agricultural evaluation of derivatives of N-Acyl-N-(m-fluoro-benzyl)-6-amino-coumarin.

ABTRACTThis study aims to design and synthesize a series of N-Acyl-N-(m-fluoro- benzyl)-6- amino-coumarins through the principle of active substructure stitching, which are based on the core structure of N-(m-fluoro-benzyl)-6-amino-coumarin. The structures of target compounds e1-e25 have been characterized by 1H NMR, 13C NMR, ESI-MS and elemental analysis. Meanwhile, their agricultural activity have been evaluated in two weeds (Amaranth and Crabgrass) and four widespread noxious pathogens (V.mali, B.cinerea, F.axysporium and C.bacteria). The herbicidal activity results showed that almost all synthetic molecules have a greater impact on the stem system than on the root. Excellent inhibition rates were discovered from compounds e2-e5 and e20-e23 against Amaranth on stems, which were above 58%(20 mg/L), 68%(100 mg/L) respectively. Compounds e2 and e21 also exhibited striking inhibition on stems growth of both weeds. Anti-pathogenic activity showed that all the compounds exerted a better inhibitory activity on B.cinerea at 20 ppm compared to control carbendazim. All the heterocyclic substituted compounds (e17-e24, >57%) made a better influence than the control (54.1%) at the100 ppm. This research provides promising herbicidal and anti-pathogenic agents that have the better effects and can be potential for further development.

Design, synthesis, antifungal activity, and 3D-QSAR of coumarin derivatives.

In our research, a series of 8-substituted coumarin derivatives were synthesized, and their structures were confirmed by FT-IR, 1H-NMR, and MS (or HRMS). In activity screening, the synthesized compounds exhibited potent antifungal activity against 4 phytopathogenic fungi: Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum, and Valsa mali. Notably, 8-chloro coumarin and ethyl 8-chloro-coumarin-3-carboxylate showed the strongest fungus inhibition with EC50 of 0.085 and 0.078 mmol/L against V. mali. Furthermore, 3D-QSAR models (CoMFA and CoMSIA) of the title compounds against V. mali were established on the basis of their antifungal activities. The results indicated that the appropriate small, hydrophilic and electron-withdrawing groups on coumarin's C-3 and C-8, respectively, could enhance the antifungal activity. The information obtained will be very helpful for designing new derivatives with high antifungal activities.

Novel 4-Methylumbelliferone Amide Derivatives: Synthesis, Characterization and Pesticidal Activities.

A series of novel 4-methylumbelliferone amide derivatives were designed, synthesized and characterized by ¹H NMR, 13C NMR and HR-ESI-MS. The structures of compounds 4bd and 4be (compounds named by authors) were further confirmed by X-ray single crystal diffraction. The acaricidal, herbicidal and antifungal activities of the synthesized compounds were assayed for their potential use as pesticide. The results indicated that compounds 4bi, 4ac and 4bd were strong acaricidals against Tetranychus cinnabarinus, with 72h corrected mortalities of greater than 80% at 1000 mg/L. Meanwhile, compounds 4bh and 4bf exhibit the strongest inhibition against the taproot development of Digitaria sanguinalis and Chenopodium glaucum, and were even more potent than the commercial herbicide Acetochlor against D. sanguinalis. In addition, compounds 4bk, 4bh and 4bp showed the highest antifungal activity against the mycelium growth of Valsa mali, which makes them more effective than commercial fungicide Carbendazim.

New angular oxazole-fused coumarin derivatives: synthesis and biological activities.

Twelve angular oxazole-fused coumarin derivatives were designed, synthesised and characterised by 1H NMR, 13C NMR and HRMS. The structure of compound 4a was further confirmed by X-ray single-crystal diffraction. The bioassay experiment results indicated that compounds 4f and 4l have high antifungal activity on the mycelium growth of 4 plant disease fungi. Especially, compound 4l has a stronger antifungal activity compare to the commercial fungicide, Carbendazim. The herbicidal activity experiment showed that 4a and 4b can significantly inhibit the taproot and caulis development of Chenopodium album seedling and have better activities than the commercial herbicide, Acetochlor.

Hypervalent iodine: a powerful electrophile for asymmetric α-functionalization of carbonyl compounds.

Environmentally friendly hypervalent iodine reagents are unusually effective promoters of asymmetric α-functionalization of carbonyl compounds. By using hypervalent iodine reagents, various substituents can be introduced into the α-position of carbonyl compounds. In the present review, we briefly survey the asymmetric α-functionalization of carbonyl compound reactions catalyzed by these hypervalent iodine reagents.