The respiratory chain succinate–ubiquinone oxidoreductase (SQR or complex II) is a promising target for fungicide discovery. As a continuation of our research work on the development of new fungicides, a series of bitriazolyl compounds were designed and synthesized in excellent yields by an ionic liquid promoted 1,3-dipolar Huisgen cycloaddition reaction of azides and akynes. These newly synthesized compounds were characterized by 1H NMR, 13C NMR and HR-MS spectroscopy. The in vitro assay indicated that several compounds displayed good inhibitory effects against porcine succinate–cyctochrome reductase (SCR) with IC50 values ranging from 2.89 to 61.19 μM. Compound 1b with an IC50 value of 2.89 μM, comparable to the commercial control penthiopyrad, was identified as the most promising inhibitor. Further evaluation of the representative compounds against respective SQR and cyt bc1 indicated that their inhibitory potency against SQR was much higher than that against cyt bc1, suggesting that SQR might be a potential target of these inhibitors. Furthermore, molecular docking studies suggested that strong hydrogen bonding and π–π stacking interactions might be responsible for a higher SQR inhibitory effect of compound 1b as compared to that of compounds 1d and 2b. Consequently, bitriazolyl compounds, a totally new skeleton that is distinct from the existing commercial SQR-inhibiting fungicides, were discovered, which could potentially be a new lead for further development of SQR inhibitors.

4-Aryl-3,4-dihydrocoumarins are a class of valuable molecules demonstrating attractive pharmaceutical and biological properties. In this paper, we designed a new and facile approach to synthesis of 4-aryl-3,4-dihydrocoumarin derivatives by Brønsted acid catalyzed Friedel–Crafts alkylation and cycloaddition reaction. With this protocol, 15 examples of 4-aryl-3,4-dihydrocoumarins were successfully prepared with yields ranging from 82 to 99%.

Pyrazoles and their derivatives are important heterocycles found in nature and present in numerous bioactive compounds. In contrast to 3 or 5-aryl pyrazole, the preparation of 4-aryl pyrazole is fairly rare. Utilizing microwave irradiation, the synthesis of 4-substituted-arylpyrazole via Suzuki cross-coupling has been developed with a wide range of substrates. The remarkable advantages of this method are mild reaction conditions, simple operation, high yield, and short reaction time. Product structures were identified by MS, 1H NMR, 13C NMR, and elemental analysis.Utilizing microwave irradiation, the synthesis of 4-substituted pyrazole via Suzuki cross-coupling has been developed with a wide range of substrates. The easy availability and the broad structural diversity of substrates make the reaction useful for the construction of 4-substituted pyrazole libraries.