Recyclable copper-catalyzed cyclization of o-haloanilides and metal sulfides: An efficient and practical access to substituted benzothiazoles

• The new MCM-41-NHC-CuI complex has been facilely prepared by a simple procedure from readily available and inexpensive reagents. • Heterogeneous copper-catalyzed cyclization of o -haloanilides and metal sulfides is first reported. • The reaction generates a wide variety of substituted benzothiazoles in mostly good to excellent yields. • This heterogenized copper(I) catalyst can be recycled up to eight times without any significant loss of activity. • Our catalytic system provides an economic and eco-friendly route to substituted benzothiazoles. An efficient heterogeneous copper-catalyzed cyclization of o -haloanilides and metal sulfides has been achieved via the C–S coupling in DMF at 80 or 140 °C in the existence of an MCM-41-bound NHC-Cu(I) catalyst and then intramolecular condensation, delivering a wide range of substituted benzothiazoles in mostly good to high yields. This new MCM-41-NHC-CuI complex can facilely be obtained by a two-step procedure starting from easily accessible and inexpensive reagents and reused more than seven times without any significant loss of its catalytic efficiency. The present protocol has been successfully applied to the gram-scale synthesis of two antitumor agents 5F203 and PMX 610.