LAUSR

We have demonstrated a new route to bis(pyrazolo[1,5- a ]pyrimidinyl)sulfanes from pyrazolo[1,5- a ]pyrimidines through I 2 -catalyzed C–H functionalization employing thiourea as the sulfur source. 3-Iodopyrazolo[1,5- a ]pyrimidines acted as the active intermediates for this radical C–H sulfenylation. This I 2 -catalyzed C–H sulfenylation has been extended toward the synthesis of sulfenylated pyrazolo[1,5- a ]pyrimidines using sulfonyl hydrazides as sulfenylating agents. Various bis(pyrazolo[1,5- a ]pyrimidinyl)sulfanes and sulfenylated pyrazolo[1,5- a ]pyrimidines have been synthesized using these simple protocols. The use of easily accessible and bench-stable reactants and reagents, metal-free catalysis, broad substrate scopes, and practicality are the attractive features of this strategy. Moreover, the usefulness of thiourea as a sulfur source in the synthesis of bis(2-phenylimidazo[1,2- a ]pyridin-3-yl)sulfane and bis(6-phenylimidazo[2,1- b ]thiazol-5-yl)sulfane derivatives has been demonstrated.