Preparation, characterization and biological activity of propargite stereoisomers
Yingshuai Liu1,2, Guozhu Sheng2, Baohong Liu2
1Shenyang Agricultural University, Plant Protection College, Shenyang, China.
Background:
Chirality plays an important role in the efficacy of pesticides, significantly influencing their biological activity, selectivity, and environmental impact. Since the first preparation of the commercial acaricide propargite in 1963, the isomeric composition has remained obscure. Propargite I and II have been referenced in various studies, yet without clear chemical structural definitions. Investigating into preparation, characterization, and biological activity of propargite stereoisomers is deemed a valuable pursuit.
Results:
Eight target propargite stereoisomers as mixture of P (trans) (Pa + Pb + Pc + Pd in a 1:1:1:1 ratio), P (cis) (Pe + Pf + Pg + Ph in a 1:1:1:1 ratio), P (1S, 2S) (Pa + Pb in a 1:1 ratio), and P (1R, 2R) (Pc + Pd in a 1:1 ratio), and as single stereoisomer of P (trans)-1 (Pa (or Pb)), P (trans)-2 (Pb (or Pa)), P (trans)-3 (Pc (or Pd)), and P (trans)-4 (Pd (or Pc)) were prepared and structurally characterized. The acaricidal activity of P (trans) (LC50 = 29.43 mg L-1) equaled approximately that of P (cis) (LC50 = 32.41 mg L-1). The P (1S, 2S) (LC50 = 17.83 mg L-1) demonstrated greater acaricidal activity than P (1R, 2R) (LC50 = 62.84 mg L-1). Notably, the P (trans)-1 (LC50 = 13.00 mg L-1) exhibited the most potent acaricidal activity among the four trans-stereoisomers. The crop safety of P (1S, 2S), P (1R, 2R), and P (trans) on cowpea seedlings were equivalent.
Conclusion:
The propargite stereoisomers P (1S, 2S) would be a promising chiral acaricide if its cost-effective synthetic methods could be developed. © 2025 Society of Chemical Industry.
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