Related Experiment Video
Updated: Jun 5, 2025

Protocols for Testing the Toxicity of Novel Insecticidal Chemistries to Mosquitoes
Published on: February 13, 2019
Structure-activity relationships between nitrile analogues and acaricidal activities against Haemaphysalis
1Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, South Korea.
Background:
A recent increase in severe fever with thrombocytopaenia syndrome (SFTS) virus cases in Korea has been observed. This virus attacks humans and animals, and no drug is available for its treatment. This study is investigating potential control measures targeting the causative agent, Haemaphysalis longicornis.
Results:
Lepidium meyenii oil was ≈8.3-, 4.2- and 4.1-fold more active than diethyltoluamide against H. longicornis larvae, nymphs and adults, respectively. The major components of L. meyenii oil were identified as benzyl nitrile (71.64%), followed by ethyl linoleic acid (13.32%), ethyl palmitate (7.81%) and 3-methoxybenzyl nitrile (2.10%). In testing individual components of the oil were tested against H. longicornis adults, the half-maximal lethal dose (LD50) values for benzaldehyde, benzyl nitrile and benzyl isothiocyanate were found to be 9.21, 9.19 and 18.26 μg cm-3, respectively. The acaricidal component was isolated and identified as benzyl nitrile. To establish the structure-activity relationships between nitrile analogues and acaricidal activities, benzyl nitrile (LD50: 0.56, 6.38 and 9.19 μg cm-3) exhibited the highest acaricidal activities against H. longicornis larvae, nymphs and adults, followed by benzoyl nitrile (3.24, 8.36 and 15.47 μg cm-3), phenyl nitrile (5.45, 9.35 and 17.48 μg cm-3) and diethyltoluamide (7.95, 14.81 and 22.12 μg cm-3). However, the presence of allyl, methyl or vinyl functional groups bound to the nitrile group abolished the acaricidal activity.
Conclusion:
These results demonstrate that L. meyenii oil, benzyl nitrile, benzoyl nitrile and phenyl nitrile represent suitable options for the secure management of H. longicornis. Nevertheless, additional research is essential to develop formulations that enhance the efficacy and safety of the aforementioned acaricides. © 2024 Society of Chemical Industry.
Related Concept Videos
Physical Properties of Amines
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the...
Nitriles to Carboxylic Acids: Hydrolysis
Amines to Amides: Acylation of Amines
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
2° Amines to N-Nitrosamines: Reaction with NaNO2
Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...

