Research Progress on Common Nitrogen-Containing Five-Membered Heterocycles in Agricultural Fungicides over the Past Five Years.

Nitrogen (N)-containing five-membered heterocycles are privileged scaffolds in the design of agricultural fungicides. This review summarizes research progress over the past five years on eight N-containing five-membered heterocycles, including thiazoles, pyrazoles, triazoles, etc. Among them, pyrazole derivatives are the most extensively studied (28.90%), followed by thiazoles (23.90%), whereas pyrrole derivatives account for the smallest proportion (1.40%). Emerging targets such as glycosylphosphatidylinositol (GPI)-anchored transmembrane protein 1 (GWT-1) and histone deacetylase (HDAC), together with advances in silico screening strategies like pharmacophore-linked fragment virtual screening (PFVS), have expanded traditional target space. In addition, three major design strategies-molecular hybridization, natural products exploration, and competitor-inspired innovation-offer advantages in structural diversification and biocompatibility optimization. However, challenges remain, including incomplete structure-activity relationship (SAR) understanding and synthetic inaccessibility of complex scaffolds. Overall, this review highlights the relationships among heterocyclic scaffolds, design strategies, and biological activity, providing guidance for developing efficient and environmentally friendly fungicides.