High value‐added use of natural plant products in crop protection: construction of novel N ‐sulfonylpyrrolomatrine derivatives from a naturally tetracyclic quinolizidine alkaloid sophocarpine via the Van Leusen reaction as aphicidal agents

BACKGROUND: Nowadays, structural modifications of natural products have been one of procedures for research and development of new pesticide candidates. Here, by using a naturally tetracyclic quinolizidine alkaloid sophocarpine as the lead compound, a series of N-sulfonylpyrrolomatrine derivatives were explored by Van Leusen [3 + 2] cycloaddition reaction as aphicidal agents. RESULTS: We prepared a series of N-sulfonylpyrrolomatrine derivatives (3a-3x) with the novel pyrrolomatrine skeleton, whose possible reaction mechanism was further proposed. Against Aphis citricola Van der Goot, N-2-chlorobenzenesulfonyl pyrrolomatrine (3k) and N-3-bromobenzenesulfonylpyrrolomatrine (3o) showed 5.4- and 4.6-fold pronounced aphicidal activity compared to sophocarpine; against Hyalopterus arundimis Fabricius, N-2-fluorobenzenesulfonylpyrrolomatrine (3h) and N-2-(trifluoromethyl)benzenesulfonylpyrrolomatrine (3q) exhibited 9.2 and 7.1 times promising aphicidal activity compared to sophocarpine. CONCLUSION: Derivatives 3h, 3k, 3o and 3q can be investigated as the leads in the future as aphicidal agents. Meanwhile, it will pave the way for future structural optimization of complex natural products containing α,β-unsaturated lactam skeleton by Van Leusen [3 + 2] cycloaddition pyrrole synthesis reaction. © 2026 Society of Chemical Industry.