Brønsted acid-promoted thiazole synthesis under metal-free conditions using sulfur powder as the sulfur source.

A Brønsted acid-promoted sulfuration/annulation reaction for the one-pot synthesis of bis-substituted thiazoles from benzylamines, acetophenones, and sulfur powder has been developed. One C-N bond and multi C-S bonds were selectively formed in one pot. The choice of the Brønsted acid was the key to the high efficiency of this transformation under metal-free conditions.