Synthesis and characterization of amphiphilic nitroxide 1,1,3,3–tetraethylisoindoline–2–oxyl–5–sodium sulfonate ( <scp>TEIOSNa</scp> )

Abstract The synthesis and characterization of an amphiphilic nitroxide to be used as a controlling agent in a nitroxide‐mediated living radical polymerization in aqueous dispersion media is presented. In the first stage of nitroxide synthesis (phthalimide protection), two reaction methods were employed: traditional and microwave. In this stage, high efficiency of benzylphthalimide with reduced reaction times was achieved using microwaves. The synthesis of sodium 1,1,3,3–tetraethylisoindoline–2–oxyl–5–sulfonate (TEIOSNa) was characterized at each stage by infrared spectroscopy and 1H and 13C nuclear magnetic resonance, and the final nitroxide was analyzed and confirmed by electron paramagnetic resonance (EPR). Because of its hydrophilic nature, the efficiency of TEIOSNa could not be determined. This work presents a new alternative for the synthesis of amphiphilic nitroxides, supported by microwaves and some adjustments during synthesis, which has allowed improved efficiency compared to those obtained with traditional methods. A route for the substitution of ethyl groups by the Grignard reaction was proposed and investigated using computational simulations with Spartan V10 Wavefunction software. These analyses allowed for the identification and postulation of possible secondary subreactions that could significantly reduce the efficiency during the synthesis of the desired nitroxide. This work proposes an efficient method to obtain TEIOSNa for direct application in CLRP in dispersed media.