A sonochemical approach to 3-(het)aryl substituted 1H-[1,3]oxazino[3,4-a]indol-1-one derivatives promoted by Pd/Cu-catalysts and ZnCl2

The one-pot synthesis of 3-(het)aryl substituted 1H-[1,3]oxazino[3,4-a]indol-1-one derivatives was accomplished via a sonochemical approach promoted by Pd/Cu-catalysts and ZnCl2 for the identification of potential inhibitors of TNF-α. [Display omitted] •First direct and one-pot synthesis of [1,3]oxazino[3,4-a]indol-1-ones is reported.•Their sonochemical synthesis involved the use of Pd/Cu-catalysts and ZnCl2.•Mild conditions, shorter duration and eco-friendly energy are key features of the methodology.•Compound 3a inhibited and interacted TNF-α in vitro and in silico, respectively. A new approach has been developed for the access of 3-(het)aryl substituted 1H-[1,3]oxazino[3,4-a]indol-1-one derivatives promoted by Pd/Cu-catalysts and ZnCl2. These compounds were prepared via a direct and one-pot method involving the coupling of 2-iodoindole derivatives with a range of terminal alkynes in the presence of (PPh3)4Pd, CuI and ZnCl2 in DMF under ultrasound. This sonochemical approach proceeded via the CC coupling followed by intramolecular cyclization (i.e. CO bond formation) in a regioselective manner in the same pot affording the desired products in good to acceptable yield. The mild reaction conditions, shorter duration and the use of eco-friendly energy are some of the key features of the current methodology. Among the synthesized compounds, the [1,3]oxazino[3,4-a]indol-1-one derivative 3a, 3c and 3f were identified as the preliminary hits when tested in vitro for their TNF-α inhibitory potential.