I2/K2S2O8‐Catalyzed Cascade Synthesis of Insecticidal 2‐Imino‐1,3‐Thiazoles: A Sustainable Approach to Bioactive Heterocycles

A highly efficient and widely applicable catalytic strategy for synthesizing 2-iminothiazoles, as well as their selenazole and oxazole analogues, was developed. This method utilizes a mild and sustainable cascade CH heterolization/CN amination reaction. Notably, the synthesized compounds exhibit insecticidal activity against Plutella xylostella larvae. This versatile methodology offers a sustainable approach for constructing bioactive heterocycles as potential insecticidal lead compounds.

Abstract

This study introduces a catalytic strategy for the synthesis of 2-iminothiazoles and their selenidazole/oxazole analogues via a cascade process. By utilizing iodine catalysis and K₂S₂O₈ as an oxidant under mild conditions, the method shows a wide substrate scope, allowing the integration of sulfur, selenium, or oxygen into heterocyclic frameworks. Mechanistic studies propose a pathway involving nucleophilic addition of thioureas to enaminones, leading to a-sulfur functionalized intermediates and subsequent intramolecular cyclization. Notably, the synthesized compounds exhibit insecticidal activity against Plutella xylostella larvae, with compound 3o displaying an LC50 of 1.759 mg/L. This versatile methodology offers a sustainable approach for constructing bioactive heterocycles as potential insecticidal lead compounds.

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