Synthesis of Imidazo[2,1‑b]thiazoles via Copper-Catalyzed A3‑Coupling in Batch and Continuous Flow

A straightforward method for the synthesis of functionalized imidazo­[2,1-b]­thiazoles starting from benzaldehydes, 2-aminothiazoles, and alkynes under copper­(I,II) catalysis was developed. The protocol allows the construction of a variety of aryl-substituted imidazo­[2,1-b]­benzothiazoles, -[2,1-b]­thiazoles, and -[2,1-b]­[1,3,4]­thiadiazoles. The reactions were easy to perform affording most of the desired products in 33–93% yields. The intensification of the process in a continuous-flow reactor increases the products’ yields up to quantitative.