Design, Synthesis and Antifungal Activity of Novel Benzoylcarbamates Bearing a Pyridine Moiety

Many natural and synthetic pyridine derivatives have good biological activity, and are widely used in the fields of pesticides and medicines. On the other hand, carbamate fungicides possess some unique properties, such as high efficiency, strong selectivity, low toxicity, and environmental friendliness, and are often used to control many plant diseases. Therefore, discovering novel pyridine-based carbamates is of great significance. In this paper, we chose the excellent fungicides tolprocarb and picarbutrazox as lead compounds, integrating benzoyl, carbamate, and pyridinyl moieties into a molecule. Thus, we designed and synthesized a series of substituted benzoyl carbamates containing a pyridine ring, and evaluated the in vitro antifungal activity. The target compounds exhibited moderate to strong bioactivity against Botrytis cinerea, among which the compounds 4d, 4f, 4g, and 4h exhibited significant activity with EC50 values (the concentration resulting in a 50% inhibition) of 6.45–6.98 μg/mL, and their activities were near or superior to that of chlorothalonil. Additionally, 4h exhibited moderate activity against Sclerotinia sclerotiorum with an EC50 value of 10.85 μg/mL.