Innovative ultrasound‐assisted synthesis of new highly functionalized pyrroles derivatives from alkynes, trichloroacet-amidine(imidate), and nitro compounds-trichloroacetonitrile adducts

Abstract

A new method for the synthesis of various pyrrole-3-carboximidamide (imidate) derivatives from the multicomponent reaction of alkynes, trichloroacetamide (imidate), and nitro compounds-trichloroacetonitrile adducts under ultrasound (US) irradiation has been reported. The reaction of nitromethane (or ethane) with trichloroacetonitrile in the presence of sodium hydride as a base led to the formation of nitro compounds-trichloroacetonitrile adducts, which subsequently led to the synthesis of new pyrrole-3-carboxyimidamide (imidate) derivatives in good yields by the addition of alkynes and trichloroacetamide (imidate). The use of an inexpensive copper (I) catalyst, under ultrasonic conditions as an energy source for 50 min, in the absence of ligands and oxidants, CH₂Cl₂ solvent, and the synthesis and identification of new compounds are important in this research. The combination of mild reaction conditions, one-pot, five-component, catalytic systems, available starting materials, and ease of purification methods facilitates the synthesis of diverse new substituted pyrroles, including amidine and imidate skeletons.