Herein, we report a mild, operationally simple, multicatalytic method for the synthesis of β,γ-unsaturated ketones via allylic acylation of alkenes. Specifically, the method combines N‑heterocyclic carbene catalysis, hydrogen atom transfer catalysis, and photoredox catalysis for cross-coupling reactions between a wide range of feedstock carboxylic acids and readily available olefins to afford structurally diverse β,γ-unsaturated ketones without olefin transposition. The method could be used to install acyl groups on highly functionalized natural-product-derived compounds with no need for substrate pre-activation, and C–H functionalization proceed with excellent site selectivity. To demonstrate the potential applications of the method, we convert a representative coupling product into various useful olefin synthons.

Based on the widespread use of hydrogen bonds in drug design, a series of aldisine derivatives containing oxime, oxime ether, and hydrazone moieties were designed and synthesized, and their antiviral, larvicidal, and fungicidal activities were evaluated for the first time. The bioassay results showed that most of these derivatives were active against tobacco mosaic virus (TMV). Hydrazone derivative 12 showed in vivo inactivation, curative, and protection activities of 52 ± 4, 49 ± 1, and 52 ± 3% at 500 mg/L, which are comparable to that of the commercial antiviral drug ningnanmycin (57 ± 3, 56 ± 2, and 59 ± 1%, respectively) at the same dose. The antiviral mechanism study showed that compound 12 could cause 20S CP (coating protein) disk fusion and disintegration, thus affecting the assembly of virus particles. The result of molecular docking indicated that there were obvious hydrogen bonds between compound 12 and TMV CP. Most derivatives were active against larvae of lepidopteran pests, such as Mythimna separata, Pyrausta nubilalis, and Plutella xylostella. Some compounds also exhibited larvicidal activities against Culex pipiens; among them compounds 9 and 13 exhibited larvicidal activities of 0.81 and 1.54 mg/L (LC50), respectively. Moreover, most of the derivatives showed broad-spectrum fungicidal activities against 14 kinds of phytopathogenic fungi at 50 mg/L.

Based on the scaffolds widely used in drug design, a series of novel tryptophan derivatives containing azepine and acylhydrazone moieties have been designed, synthesized, characterized, and evaluated for their biological activities. The bioassay results showed that the target compounds possessed moderate to good antiviral activities against the tobacco mosaic virus (TMV), among which compounds 5c, 6a, 6h, 6t, 6v, and 6y exhibited higher inactivation, curative, and protection activities in vivo than that of ribavirin (40 ± 1, 37 ± 1, 39 ± 2% at 500 mg/L). Especially, 6y showed comparable activities to that of ningnanmycin (57 ± 2, 55 ± 3, 58 ± 1% at 500 mg/L). Meanwhile, we were pleased to find that almost all these derivatives showed good larvicidal activities against Plutella xylostella. Meanwhile, these derivatives also showed a broad spectrum of fungicidal activities.

Based on the scaffolds widely used in drug design, a series of novel tryptophan derivatives containing 2,5-diketopiperazine and acyl hydrazine moieties have been designed, synthesized, characterized, and evaluated for their biological activities. The bioassay results showed that the target compounds possessed moderate to good antiviral activities against tobacco mosaic virus (TMV), among which compounds 4, 9, 14, 19, and 24 showed higher inactivation, curative, and protection activities in vivo than that of ribavirin (39 ± 1, 37 ± 1, 39 ± 1 at 500 mg/L) and comparable to that of ningnanmycin (58 ± 1, 55 ± 1, 57 ± 1% at 500 mg/L). Thus, these compounds are a promising candidate for anti-TMV development. Most of these compounds showed broad-spectrum fungicidal activities against 13 kinds of phytopathogenic fungi and selective fungicidal activities against Alternaria solani, Phytophthora capsica, and Sclerotinia sclerotiorum. Additionally, some of these compounds exhibited larvicidal activities against Tetranychus cinnabarinus, Plutella xylostella, Culex pipiens pallens, Mythimna separata, Helicoverpa armigera, and Pyrausta nubilalis.

Marine natural products have attracted more and more attention in drug research and development due to their unique structure, diverse biological activities, and novel mode of action. Using antiviral alkaloid aldisine as the lead compound and drawing on the hydrogen bond effect widely used in drug design, derivatives containing oxime and hydrazone moieties were designed and synthesized by introducing functional groups with hydrogen-bond receptors or donors into molecules. The configuration of derivatives was systematically studied through nuclear Overhauser effect (NOE) spectroscopy and single crystal analysis. The antiviral activity test result showed that most derivatives had antiviral activity against tobacco mosaic virus (TMV), and some compounds had better activity than the commercial antiviral drug ribavirin, especially compounds 2 and 24, which had comparable activity to the most effective commercial antiviral drug ningnanmycin. Preliminary mode of action studies showed that compound 2 could affect the assembly of rod-shaped TMVs by promoting the aggregation and fragmentation of TMV coat proteins. Molecular docking experiments demonstrated that the introduction of oxime and hydrazone moieties could indeed increase the hydrogen bond between molecules and target proteins. In addition, we conducted fungicidal and larvicidal activities study of these derivatives. Most of these derivatives had good larvicidal activities against Mythimna separata and Plutella xylostella and showed broad-spectrum fungicidal activities.