Direct thiocarbamation of imidazoheterocycles via dual C-H sulfurization.

A copper-catalyzed DTBP oxidative dual C-H sulfurization has been developed for the direct thiocarbamation of imidazopyridines using a combination of elemental sulfur and formamides as carbamothioyl surrogates. NBS (bromo succinimide) was found to promote the thiocarbamation in good yields. This dual C-H sulfurization strategy enables access to a wide range of carbamothioyl imidazoheterocycles without the use of highly toxic phosgene.

Sulfite-Promoted Synthesis of N-Difluoromethylthioureas via the Reaction of Azoles with Bromodifluoroacetate and Elemental Sulfur.

A sulfite-promoted transformation of azoles into N-difluoromethylthioureas through N-difluoromethylation and sulfuration has been developed. In this reaction, inexpensive ethyl bromodifluoroacetate and nontoxic elemental sulfur were used as the difluoromethylation and sulfuration reagents, respectively. A variety of azoles, including benzimidazoles, imidazoles, and triazoles, performed well to afford a broad range of azole thioureas in moderate to good yields.

Isothiocyanation of amines using the Langlois reagent.

The Langlois reagent was found to be effective for the isothiocyanation of primary amines in the presence of copper iodide and diethyl phosphonate.

Oxidative dual C-H thiolation of imidazopyridines with ethers or alkanes using elemental sulphur.

Dual C-H thiolation reactions using elemental sulphur remain a challenge. This communication discloses an oxidative radical dual sp2/sp3 C-H thiolation strategy for the coupling of imidazopyridines with ethers or alkanes using elemental sulphur.