10.1002/ps.2780450411
The research aimed to develop a novel synthesis route for the insecticides MTI-800 and desfluoro MTI-800, and to evaluate their insecticidal activities against the tobacco caterpillar Spodoptera litura. The study utilized a tandem Friedel-Crafts acylation and other chemical reactions, diethyl sulfate played a crucial role as a reagent in the alkylation step of the synthesis process. Specifically, it was used to convert the phenolic compound 3-(4-hydroxyphenyl)-3-methyl-2-butanone (2) into 3-(4-ethoxyphenyl)-3-methyl-2-butanone (3). The synthesis process included multiple steps, including acylation, alkylation, aldol condensation, reduction, chlorination, and hydrogenation, to produce the target compounds and their intermediates. The results showed that MTI-800 (7b) and desfluoro MTI-800 (7a) exhibited excellent insecticidal activity comparable to the well-known synthetic pyrethroids fenvalerate and cypermethrin. The study concluded that the central link structure and the presence of a fluoro substitution significantly influenced the insecticidal activity, with the alkane central link showing high activity regardless of the fluoro substitution. The research provides a simpler and cost-effective synthesis route for these insecticides and offers insights into the structure-activity relationship for further development of effective insecticidal compounds.
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