An efficient protocol to direct sulfonamidation or sulfonation of electron-deficient alkenes for furnishing alkylsulfonamides or sulfonates has been achieved.
Plant diseases are seriously endangering agricultural production. The emergence of drug resistance has brought great challenges to the prevention and control of plant diseases. There is an urgent need for the emergence of new drug candidates. In this work, we achieved the efficient synthesis of pulmonarins A and B in 64% and 59% overall yield, respectively. Pulmonarins A and B were found to have good antiviral activities against tobacco mosaic virus (TMV) for the first time. A series of pulmonarin derivatives were designed, synthesized, and evaluated for their antiviral and fungicidal activities systematically. Most compounds displayed higher anti-TMV activities than commercial ribavirin. Compounds 6a, 6c, and 6n with better inactivation effects than ningnanmycin emerged as new antiviral candidates. We selected 6c for further antiviral mechanism research, which revealed that it could inhibit virus assembly by interacting with TMV coat protein (CP). The molecular docking results further confirmed that these compounds could interact with CP through hydrogen bonding. These compounds also displayed broad spectrum fungicidal activities. Especially compound 6u with prominent antifungal activity emerged as a new fungicidal candidate for further research. The current work provides a reference for understanding the application of pulmonarin alkaloids in plant protection.
Plant
diseases caused by plant viruses and pathogens seriously
affect the production and storage of food crops. With the emergence
of drug resistance, it is very difficult to control. Natural products
are the source of new drug discovery. Here, the natural product streptindole
was found to have good antiviral activity against tobacco mosaic virus
(TMV) and fungicidal activities against 14 kinds of phytopathogenic
fungi. A series of derivatives of streptindole were designed, synthesized,
and evaluated for their antiviral and fungicidal activities. Compounds 4, 5, 11, 12c, 12d, 13d, and 13i–13l showed
higher anti-TMV activities than ribavirin (inhibitory rate: 38, 37,
and 40% at 500 μg/mL for inactivation, curative, and protection
activity in vivo, respectively), among which compound 12d (inhibitory rate: 57, 55, and 53% at 500 μg/mL for
inactivation, curative, and protection activity in vivo, respectively) with excellent antiviral activity was further evaluated
for the mode of action. The mechanism research revealed that 12d can break the three-dimensional structure of TMV coat
protein (CP) through hydrogen bonds, thus inhibiting the assembly
of virus particles. The molecular docking result showed that compound 12d did exhibit strong interaction with TMV CP. The derivatives
of streptindole also displayed broad-spectrum fungicidal activities.
The current study provided valuable insights into the antiviral and
fungicidal activities of streptindole derivatives.
Plant viruses and fungi are a serious threat to food security and natural ecosystems. The efficient and environmentfriendly control methods are urgently needed to help safeguard such resources. Here, we achieved the efficient synthesis of toad alkaloid dehydrobufotenine in eight steps with an overall yield of 8% from 5-methoxyindole. A series of dehydrobufotenine derivatives were designed, synthesized, and evaluated for their antiviral and fungicidal activities systematically. It was found for the first time that these compounds have good anti-plant virus activities and anti-plant pathogen activities. The antiviral activities of 21 compounds were similar to or better than those of ribavirin. Compounds 12 and 17 displayed better antiviral activities than ningnanmycin which is perhaps the most effective anti-plant virus agent. The antiviral mechanism research study of 12 revealed that it could make 20S CP disk fusion and aggregation. Further molecular docking results showed that there are hydrogen bonds between compounds 12, 17, and tobacco mosaic virus CP. The docking results are consistent with the antiviral activity. These compounds also displayed broad-spectrum fungicidal activities against 14 kinds of fungi, especially for Sclerotinia sclerotiorum. In this work, the synthesis, structure optimization, structure−activity relationship studies, and mode of action research of dehydrobufotenine alkaloids were carried out. It provides a reference for the development of the anti-plant virus agent and anti-plant pathogen agent from toad alkaloids.
The sulfonamidation of diverse aryl olefins is facile access to synthesize alkylsulfonamides. Here we report a novel protocol utilizing radical-mediated addition and thiol-assisted strategy to achieve hydrosulfamoylation of diverse styrenes...
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