Transition Metal Catalyst Free and Single‐Step Synthesis of Significant Thiosemicarbazones via Oxidative Coupling Strategy

Abstract

AbstractThe efficacy and selectivity of the transition metal‐free catalysis have been emphasized in constructing thiosemicarbazone derivatives from the dehydrogenative coupling of alcohols and thiosemicarbazides under aerobic conditions. A broad spectrum of thiosemicarbazones was obtained in good‐to‐excellent yields up to 90 %, with water as the only by‐product. The catalytic synthesis worked in an atom‐economical fashion in the absence of any oxidant with only 1 mmol of the base loading per mmol of the substrates. Further, the impact of different temperatures, solvents, bases, and base loading of the coupling reaction has been explored. A probable pathway that involves the generation of an aldehyde intermediate to thiosemicarbazones, which releases only water has been proposed.