An Expedient Flow Chemistry Approach to Substituted 1,4‐Dimethylcarbazoles

Abstract A simple, expedient continuously scalable flow chemistry synthesis of a range of 1,4‐dimethylcarbazoles from substituted indoles and 2,5‐hexanedione in the presence of K‐10 (montmorillonite clay) is reported. Optimization of the flow conditions led to the development of an in‐house K‐10/sand Omnifit TM catalyst column that at 140 °C and 0.4 mL.min −1 afforded >90% conversion of the selected indole to the desired 1,4‐carbazole. This equates to a ca 80 mg.h −1 production rate. The reaction was tolerant of electron donating indoles but not electron withdrawing indoles.