A continuous flow method for the desulfurization of substituted thioimidazoles applied to the synthesis of new etomidate derivatives

• Marcus Baumann, Ian R Baxendale

• Durham University, Department of Chemistry, Durham, UK

A simple yet robust flow set-up for the efficient desulfurization of a series of thioimidazoles is presented generating the corresponding imidazole derivatives in high yields. The strategic choice of peristaltic over piston pumps allowed reliable delivery of the heterogeneous stream of thioimidazole substrate into a T-piece where it reacted with NaNO2 in the presence of acetic acid. This approach enabled the controlled and safe formation of the reactive nitrosonium species without uncontrolled exposure to hazardous nitrous oxide by-products as observed in related batch protocols. The value of the resulting imidazole products was further demonstrated by their conversion into various esters representing new derivatives of the known analgesic etomidate via an efficient one pot Corey-Gilman-Ganem oxidation procedure.

Read the publication that featured this abstract