Streamlined Routes to Phenacyl Azides and 2,5-Diarylpyrazines Enabled by Deep Eutectic Solvents

A Deep Eutectic Solvent like choline chloride/glycerol (1:2 mol mol–1) proved to be an effective, sustainablereaction medium to easily synthesize both phenacyl azides andsymmetrical 2,5-diarylpyrazines of interest in pharmacologyand in coordination chemistry. Notable features of our reportinclude: (i) nucleophilic substitution reactions ofα-halo carb-onyl compounds to the corresponding phenacyl azides compatible with the eutectic mixture, (ii) the reduction of phenacylazides toα-amino carbonyl compounds, which undergo spon-taneous dimerisation/cyclisation/aromatisation in the same eu-tectic mixture to provide valuable pyrazines. Telescoped, one-pot, two-steps stoichiometric/catalytic processes have alsobeen successfully developed to furnish 2,5-diarylpyrazines in upto 95 % yield.