Sonochemical assisted synthesis of 𝛼-arylation of ketones: a rapid access to isoquinolinone derivatives

An efficient procedure for the synthesis of pyrido [2,1-a] isoquinoline derivatives in excellent yields was investigated under ultrasonic irradiation at room temperature. The advantages of this procedure compared to report methods are short time of reaction, high yields of product, easy separation of product, clean mixture of reaction and green media for performing reaction. the isoquinolin-1(2H)-one derivatives have attracted considerable interest and continuing efforts have been devoted to develop convenient and efficient methods for their synthesis. In the current study we have demonstrated the effectiveness of ultrasound, a source of green energy, in accessing various isoquinolin-1(2H)-one derivatives via the sequential two-step reaction in a single pot. The methodology involved ultrasound assisted Cu-catalyzed a-arylation of ketones with 2-iodobenzamide (via a C-C bond formation) followed by intramolecular cyclization (via the C-N bond formation) in the same pot. This appeared to be the first example of application of ultrasound in the a-arylation of ketones. The role of ultrasound, catalyst, base and solvent in the current transformation was evaluated and the generality as well as scope of the methodology was examined via synthesizing a variety of compounds in good to acceptable yields. A plausible reaction mechanism consisting of the catalytic cycle for C-C bond formation in the presence of Cu-catalyst has been proposed. The application potential of the methodology was demonstrated further via synthesizing a reported bioactive 3- aryisoquinolinamine derivative of medicinal significance.