Sustainability-driven optimisation of sonochemical iodination of anilines

In this work, we report our approach for the synthesis of iodinated anilines by exploiting the use of ultrasound activation. We have optimised the reaction conditions by quantitatively assessing the environmental impact of each parameter and maximising its overall efficiency. The reaction medium, acidic additives, iodine sources, and reaction parameters were all optimised using different indicators, such as the E-factor, kg CO2 equivalents, and solvent section guide. Ultrasound assistance has proven to be optimally effective, allowing energy saving (almost 50 % energy consumption reduced), short reaction times (only 1 h reaction time), and selectivity. A final comparison among commonly utilised iodination methods shows the benefits in terms of sustainability of the proposed sonochemical protocol, with an E-factor reduction of at least one order of magnitude.