Design and Synthesis of Scopoletin Sulfonate Derivatives as Potential Insecticidal Agents.

(1) Background: Scopoletin and scoparone, two naturally occurring coumarins, have garnered considerable attention and have been introduced to the market in China due to their high insecticidal efficacy and low toxicity. To investigate the structure-activity relationship of these coumarins, a series of scopoletin derivatives with aryl sulfate at C7 and different substitutes at C3 were designed and synthesized, and their insecticidal activity was studied. (2) Methods: A total of 28 new scopoletin derivatives were designed and synthesized. Most target compounds exhibited moderate insecticidal activity against the phytophagous mite Tetranychus cinnabarinus and the brine shrimp Artemia salina. (3) Results: Among these compounds, compounds 5a and 5j possessed the best insecticidal activities against T. cinnabarinus, with LC50 values of 57.0 and 20.0 µg/mL, respectively, whereas that of the control drug was 15.0 µg/mL. Compound 4j exhibited selective insecticidal activities against A. salina, with an LC50 value of 9.36 µg/mL, whereas its LC50 value against T. cinnabarinus was 93.0 µg/mL. The enzymatic inhibitory activity on acetylcholinesterase (AChE) showed a consistent tendency with the insecticidal activity. Further molecular docking analyses predicted the binding conformations of these compounds, which showed a good correlation between the insecticidal activity and the binding scores. (4) Conclusions: In general, a decreased electron cloud density of the Δ3,4 olefinic bond is beneficial for improving the insecticidal activity against both T. cinnabarinus and A. salina. In addition, naphthyl or benzene groups with a sulfate ester at the C7 position could further improve the insecticidal activity against A. salina. AChE was implied to be a site of action for potential insecticidal activity. The results provide insight into the rational design of a new generation of effective coumarin insecticides.

4-Methylumbelliferone fused oxazole thioether derivatives: synthesis, characterization and antifungal activities.

Series of thioether derivatives containing 4-methylumbelliferone fused oxazole moiety were designed and synthesised, their structures were fully characterized by 1H NMR, 13C NMR and HR-ESI-MS as well. Moreover, the in vitro antifungal potency of the title compounds were preliminarily evaluated for their possible use as a fungicide. Meanwhile, ethyl thioethers 3aa and 3ba displayed remarkable inhibitory effect against the mycelium growth of Valsa mali and Botrytis cinerea with EC50 of 12-16 µg/mL. Furthermore, compounds 3aa and 3ba also exhibited > 88% protective and curative effect against B. cinerea on tomato fruits at 90 µg/mL. Additionally, the environmental toxicity of the title compounds against the brine shrimp Artemia salina were evaluated as well. The results indicated that most of the title compounds exhibited weak toxic to aquatic organism A. salina.

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 Trifluoromethylcoumarinyl Urea Derivatives: Synthesis, Characterization, Fluorescence, and Bioactivity.

A series of novel trifluoromethylcoumarinyl urea derivatives were designed, synthesized, and characterized by ¹H-NMR, 13C-NMR, and HR-ESI-MS. The fluorescence spectra of the target compounds were recorded. The spectra show that most of the title compounds glow green with λmaxem of 500-517 nm, while compounds 5r, 5s, 5u, and 5l (compounds named by authors) glow violet with λmaxem of 381-443 nm. Moreover, the herbicidal and antifungal activities of the synthesized compounds were evaluated for their potential use as pesticides. The results indicate that compound 5f against the caulis of Amaranthusretroflexus and compounds 5j and 5l against the taproot of Digitariasanguinalis are equivalent to the commercial herbicide Acetochlor. Nine of the title compounds are more antifungal than commercial fungicide Carbendazim against Botrytis cinerea.

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.

Novel triacsin C analogs as potential antivirals against rotavirus infections.

Recently our group has demonstrated that cellular triglyceride (TG) levels play an important role in rotavirus replication. In this study, we further examined the roles of the key enzymes for TG synthesis (lipogenesis) in the replication of rotaviruses by using inhibitors of fatty acid synthase, long chain fatty acid acyl-CoA synthetase (ACSL), and diacylglycerol acyltransferase and acyl-CoA:cholesterol acyltransferase in association with lipid droplets of which TG is a major component. Triacsin C, a natural ACSL inhibitor from Streptomyces aureofaciens, was found to be highly effective against rotavirus replication. Thus, novel triacsin C analogs were synthesized and evaluated for their efficacies against the replication of rotaviruses in cells. Many of the analogs significantly reduced rotavirus replication, and one analog (1e) was highly effective at a nanomolar concentration range (ED(50) 0.1µM) with a high therapeutic index in cell culture. Our results suggest a crucial role of lipid metabolism in rotavirus replication, and triacsin C and/or its analogs as potential therapeutic options for rotavirus infections.