Functionalization of C-H bonds in acetophenone oximes with arylacetic acids and elemental sulfur.

Fused thieno[3,2- d ]thiazoles were synthesized via a coupling of acetophenone ketoximes, arylacetic acids, and elemental sulfur in the presence of Li 2 CO 3 base. Functionalities including chloro, bromo, fluoro, trifluoromethyl, and pyridyl groups were compatible with reaction conditions. High yields and excellent regioselectivities were obtained even if meta -substituted ketoxime acetates were used. Ethyl esters of heteroarylacetic acids were competent substrates, which is very rare in the literature. Our method would offer a convenient protocol to afford polyheterocyclic structures from simple substrates.