Expanding the Versatile Reactivity of Diazido Malonic Acid Esters and Amides: Decarboxylation and Imine Formation

Abstract

Herein, we advance our understanding on the divergent reaction pathways that are possible, starting from diazido diethyl malonate (easily generated through the oxidative diazidation of diethyl malonate with iodine and sodium azide in DMSO at room temperature): when treated with amines, diazidated malonamides are rapidly formed, many of which then undergo a formal substitution reaction with alkylamines leading to imino malonamides under basic conditions. Using the established conditions of CuAAC click reactions with terminal alkynes, the diazidated malonamides are alternatively transformed into their corresponding bistriazole derivatives, a reaction that is also achievable with diazido diethyl malonate. We now demonstrate that the malonic diester bistriazoles undergo a smooth decarboxylation in the presence of amines, creating novel bistriazole variants derived from acetamides. All protocols presented herein are experimentally simple and enhance the variety of products obtainable from malonic acid derivatives.