Synthesis of biheteroaryls via2-methyl quinoline C(sp3)-H functionalization under metal-free conditions

An acetic acid-promoted C(sp3)-H functionalization of 2-methyl quinoline, enaminoesters and elemental sulfur for the synthesis of 3,4,5-trisubstituted isothiazoles under metal-free conditions has been developed. This approach provides viable access to various 5-(quinolin-2-yl)isothiazoles in moderate to good yields with good functional group tolerance. Moreover, the success of the gram-scale reaction gives this reaction a great potential application.