Synthesis of a library of 2-aryl-2H-tetrazole-5-carboxamides for photoaffinity labeling of aminergic G-protein coupled receptors

A four-step approach to 2-aryl-2H-tetrazole-5-carboxamides bearing GPCR-focused N-substituted piperazine residues involves ‘SAFE’ diazotransfer onto 1-(piperazin-1-yl)butane-1,3-diones followed by [3+2] cycloaddition of arenediazonium cations at the intermediate ααα-diazo acetamides. The compounds prepared are intended for photoaffinity labeling of aminergic G-protein coupled receptors.