Novel 1,3,4-oxadiazole hybrids of 3-n-butylphthalide derivatives as potential anti-ischemic stroke agents.

In continuation of our program to search for novel potential anti-ischemic stroke agents, a series of 1,3,4-oxadiazole and sulfoxide hybrids of phthalide derivatives was designed and synthesized in this study to evaluate their anti-ischemic stroke activity. Among them, compounds 5b, 5d, 5 l, and 5 m exhibited excellent inhibitory effects on platelet aggregation induced by adenosine diphosphate (ADP) and arachidonic acid (AA). In particular, compound 5b possessed considerable antithrombotic activity in animal models, as demonstrated by the effective alleviation of carrageenan-induced and FeCl3-induced thrombosis in tail and carotid arteries, respectively. Notably, intraperitoneal administration of compound 5b could better protect the brain from injury caused by ischemia/reperfusion in rats compared with precursor 3-n-butylphthalide. Further pharmacokinetics, liver microsomal stability, and PAMPA-BBB assays also indicated that compound 5b had relatively high bioavailability, metabolic stability, and BBB permeability. Moreover, compound 5b showed a safety profile that was superior to the clinical drugs clopidogrel, aspirin, and 3-n-butylphthalide in the mouse-tail bleeding assay. Finally, molecular docking predicted that the potential target of the antiplatelet aggregation activity of compound 5b was P2Y12 receptor. This research provides a novel candidate compound for the treatment of ischemic stroke.

Synthesis and antifungal activities of small molecule arylthiazolamine derivatives.

Developing new fungicides to compensate for the deficiencies of existing fungicides resistance in phytopathogenic fungi is a research hotspot in the field of pesticides. Aiming to discover novel template small molecules with excellent antifungal activity, thirty-eight arylthiazolamine derivatives were synthesized through bromination, cyclization, halogenation, and acylation reactions. The synthesized compounds were screened for antifungal activity against ten typical fungal pathogens, and some halogenated arylthiazolamines and amides exhibited excellent broad-spectrum antifungal activity, especially compounds 4m (3.96-47.76 µg/mL), 5k (0.10-7.70 µg/mL) and 5n (2.08-11.21 µg/mL). Among them, compound 5k provided comparable protection and curative effects to chloroticonil and boscalid against B. dothidea and V. mali infection in apple and apple tree branches, respectively, and it could exert antifungal effects by inhibiting the differentiation of mycelium spores, spore germination, and bud tube growth. This study provides high-efficiency and inexpensive candidate compounds for managing of diseases caused by plant pathogenic fungi.

Synthesis and evaluation of imidazo[1,2-a]quinoxaline derivatives as potential antifungal agents against phytopathogenic fungi.

To discover novel and effective potential agricultural antifungal agents, various kinds of imidazo[1,2-a]quinoxaline derivatives were designed, and synthesized from available and inexpensive reagents. Their antifungal activities were first evaluated against ten typical phytopathogenic fungi. The in vitro antifungal activity showed that some compounds exhibited more obvious broad-spectrum fungicidal activity than the two commercially-available fungicides chlorothalonil and hymexazol. Valsa mali and Botrytis cinerea strains exhibited the highest susceptibility with EC50 values of 1.4-27.0 µg/mL to more than ten compounds. Compounds 5c and 5f showed the most promising inhibitory effects against Valsa mali (EC50 = 5.6 µg/mL) and Fusarium solani (EC50 = 5.1 µg/mL), respectively. Preliminary studies on the mechanism of action indicated that the imidazo[1,2-a]quinoxaline skeleton likely exerted its antifungal effects by disrupting hyphal differentiation, spore germination, and germ tube growth. Moreover, the cell experiment results indicated that these target compounds possessed good safety to BV2 cells. Overall, compounds 5c and 5f can be considered candidate compounds against specific fungi for further detailed research. This study can provide a theoretical basis for the application of imidazo[1,2-a]quinoxaline scaffolds as novel fungicides in agriculture.

Design and synthesis of novel 2,2-dimethylchromene derivatives as potential antifungal agents.

In order to find novel environment-friendly and effective antifungal agents, four series of 2,2-dimethyl-2H-chromene derivatives were designed, synthesized and characterized by spectroscopic analysis. The antifungal activities of all the target compounds against nine phytopathogenic fungi were evaluated in vitro. Preliminary results indicated that most of the target compounds exhibited obvious antifungal activity at the concentration of 50 µg/mL. Among them, compound 4j displayed more promising antifungal potency against Fusarium solani, Pyricularia oryzae, Alternaria brassicae, Valsa mali and Alternaria alternata strains than the two commercially available fungicides chlorothalonil and hymexazol, with the corresponding EC50 values of 6.3, 7.7, 7.1, 7.5, 4.0 µg/mL, respectively. Moreover, the cell experiments results suggested that the target compounds had low cytotoxicity to the PC12 cell. This research will provide theoretical basis for the future application of 2,2-dimethyl-2H-chromenes as botanical fungicides in agriculture. Four series of novel, potent and low-toxicity 2,2-dimethyl-2H-chromene derivatives were designed and synthesized as agricultural antifungal agents. The in vitro antifungal experiments showed that compound 4j exhibited higher antifungal efficacy against five strains than the two commercially-available fungicides chlorothalonil and hymexazol.