Convenient synthesis of highly functionalized isoxazoles including an amidine skeleton based on trichloroacetamidine, alkynes, and hydroxyimidoyl chloride

The synthesis of functionalized isoxazole-4-carboximidamide with appropriate yields through a novel four-component reaction from alkynes, hydroxyimidoyl chloride, trichloroacetonitrile, and various amines is a remarkable achievement in heterocycle chemistry. This strategy offers a direct and efficient route to access different isoxazoles with amidine substitution from readily available starting materials. The use of copper (I) as a catalyst, without adding ligand, in THF solvent, and with the help of ultrasonic conditions for 45 min at room temperature highlights the importance of transition metal catalysis in this process.