Phosphorylation of Benzimidazole-2-thiones by Chloroethynylphosphonate

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

“…It is characterized by a selective 5- endo - dig cyclization to the corresponding five-membered rings. The obtained new compounds are of special interest due to the practical utility of the formed fused heterocycles, such as indoles [1], thiazolo[2,3- b ][1,3,4]thiadiazole [2], and benzo[4,5]imidazo[2,1- b ]thiazole [3], as well as due to the simultaneous presence of a biologically active phosphorus function in the molecules. Recently, we have shown that the reaction of chloroethynylphosphonates with 2-aminopyridines proceeds through a 5- endo - dig cyclization to form imidazo[1,2- a ]pyridines [4].…”

Hypervalent Sulfur Derivatives as Sulfenylating Reagents: Visible-Light-Mediated Direct Thiolation of Activated C(sp2)–H Bonds with Dihalosulfuranes

“…In contrast to cyclic 1,3-diketones, acetylacetone furnished imidazothiazolium salt 10c , as evidenced by X-ray analysis. Notably, imidazothiazolium salts are only scarcely presented in the literature. − Presumably, compound 10c results from the intramolecular cyclization of initially formed acyclic sulfide. Notably, such a cyclization is impossible in the case of cyclic ketones as a result of geometry constraints (see the Supporting Information for the X-ray data for compound 10c and additional discussion).…”