In this study, using the botanical active component thiochromanone as the lead compound, a total of 32 new thiochromanone derivatives containing a carboxamide moiety were designed and synthesized and their in vitro antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas oryzae pv. oryzicolaby (Xoc), and Xanthomonas axonopodis pv. citri (Xac) were determined, as well as their in vitro antifungal activities against Botryosphaeria dothidea (B. dothidea), Phomopsis sp., and Botrytis cinerea (B. cinerea). Bioassay results demonstrated that some of the target compounds exhibited moderate to good in vitro antibacterial and antifungal activities. In particular, compound 4e revealed excellent in vitro antibacterial activity against Xoo, Xoc, and Xac, and its EC₅₀ values of 15, 19, and 23 μg/mL, respectively, were superior to those of Bismerthiazol and Thiodiazole copper. Meanwhile, compound 3b revealed moderate in vitro antifungal activity against B. dothidea at 50 μg/mL, and the inhibition rate reached 88%, which was even better than that of Pyrimethanil, however, lower than that of Carbendazim. To the best of our knowledge, this is the first report on the antibacterial and antifungal activities of this series of novel thiochromanone derivatives containing a carboxamide moiety.

A series of novel thiochromanone derivatives containing a sulfonyl hydrazone moiety were designed and synthesized. Their structures were determined by ¹H-NMR, ¹³C-NMR, and HRMS. Bioassay results showed that most of the target compounds revealed moderate to good antibacterial activities against Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicolaby, and Xanthomonas axonopodis pv. citri. Compound 4i had the best inhibitory activity against Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicolaby, and Xanthomonas axonopodis pv. citri, with the EC₅₀ values of 8.67, 12.65, and 10.62 μg/mL, which were superior to those of Bismerthiazol and Thiodiazole-copper. Meanwhile, bioassay results showed that all of the target compounds proved to have lower antifungal activities against Sclerotinia sclerotiorum, Fusarium oxysporum, Gibberella zeae, Rhizoctonia solani, Verticillium dahlia, and Botrytis cinerea than those of Carbendazim.

This study involved the design and synthesis of a series of novel 4-chromanone-derived compounds. Their in vivo anti-cucumber mosaic virus (CMV) activity in field trials against CMV disease in Passiflora spp. was then assessed. Bioassay results demonstrated that compounds 7c and 7g exhibited remarkable curative effects and protection against CMV, with inhibition rates of 57.69% and 51.73% and 56.13% and 52.39%, respectively, surpassing those of dufulin and comparable to ningnanmycin. Field trials results indicated that compound 7c displayed significant efficacy against CMV disease in Passiflora spp. (passion fruit) after the third spraying at a concentration of 200 mg/L, with a relative control efficiency of 47.49%, surpassing that of dufulin and comparable to ningnanmycin. Meanwhile, nutritional quality test results revealed that compound 7c effectively enhanced the disease resistance of Passiflora spp., as evidenced by significant increases in soluble protein, soluble sugar, total phenol, and chlorophyll contents in Passiflora spp. leaves as well as improved the flavor and taste of Passiflora spp. fruits, as demonstrated by notable increases in soluble protein, soluble sugar, soluble solid, and vitamin C contents in Passiflora spp. fruits. Additionally, a transcriptome analysis revealed that compound 7c primarily targeted the abscisic acid (ABA) signaling pathway, a crucial plant hormone signal transduction pathway, thereby augmenting resistance against CMV disease in Passiflora spp. Therefore, this study demonstrates the potential application of these novel 4-chromanone-derived compounds as effective inducers of plant immunity for controlling CMV disease in Passiflora spp. in the coming decades.

In this study, a series of novel pyrimidine derivatives incorporating an 1,1,2-trifluoro-1-butene moiety were synthesized and their structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS. The bioassay results demonstrate that 4-methyl-2-[(3,4,4-trifluorobut-3-en-1-yl)thio]-6-(trifluoromethyl)pyrimidine exhibits comparable in vitro antifungal activity against Aspergillus niger (64.55 and 48.85%, respectively) at concentrations of 100 and 50 μg/mL when compared to Prochloraz. Additionally, 4-methyl-2-[(3,4,4-trifluorobut-3-en-1-yl)sulfonyl]-6-(trifluoromethyl)pyrimidine demonstrates superior nematocidal activity against Caenorhabditis elegans at concentrations of 100 and 50 μg/mL after 48 h with corrected mortality rates of 89.65 and 79.47%, respectively, surpassing those observed for ethoprophos. To the best of our knowledge, this study presents the first report on the synthesis and antifungal and nematocidal activities of novel pyrimidine derivatives incorporating an 1,1,2-trifluoro-1-butene moiety.

In this study, a series of novel pyrimidine derivatives incorporating amide and 1,3,4-thiadiazole thioether moieties were synthesized and their structures were confirmed using ¹H NMR, ¹³C NMR, and HRMS analyses. Bioassay results demonstrated that compound 2-{[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]thio}-N-[5-(propylthio)-1,3,4-thiadiazol-2-yl]acetamide exhibited superior antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo), with an inhibition rate of 100% at a concentration of 200 μg/mL, compared to thiodiazole copper. Meanwhile, compound 2-[(4,6-dimethylpyrimidin-2-yl)thio]-N-[5-(ethylthio)-1,3,4-thiadiazol-2-yl]acetamide displayed remarkable antifungal activity against Gilbertella persicaria (G. persicaria), with an EC₅₀ value of 6.71 μg/mL, surpassing that of prochloraz. To the best of our knowledge, this study represents the first report on the synthesis and bioactivity evaluation of pyrimidine derivatives incorporating amide and 1,3,4-thiadiazole thioether moieties.

In this study, a series of novel vanillic acid derivatives incorporating 1,3,4-oxadiazole and thioether moieties were synthesized and their structures were confirmed using ¹H NMR, ¹³C NMR, and HRMS techniques. The results of bioactivity determination demonstrated that the target compounds exhibited moderate to good in vitro antibacterial activities against Xanthomonas axonopodis pv. citri (Xac) and Xanthomonas oryzae pv. oryzae (Xoo). Particularly, compound 2-{4-[(4-chlorobenzyl)oxy]-3-methoxyphenyl}-5-(propylthio)-1,3,4-oxadiazole displayed remarkable antibacterial activities against Xac and Xoo with EC₅₀ values of 5.58 and 18.82 μg/mL respectively, surpassing those of bismerthiazol and thiodiazole copper. To the best of our knowledge, this study presents the first report on the synthesis and antibacterial activity evaluation of vanillic acid derivatives incorporating 1,3,4-oxadiazole and thioether moieties.