Synthesis of 3-Methylthioindoles via Intramolecular Cyclization of 2-Alkynylanilines Mediated by DMSO/DMSO-d₆ and SOCl₂

Main observation and conclusion The intramolecular cyclization of 2-alkynylanilines mediated by DMSO/SOCl2 was found to afford biologically interesting 3-methylthioindoles, which are rarely obtained by the exiting methods. DMSO could also be replaced with its deuterated counterpart, enabling the method applicable to the construction of indole skeleton bearing a SCD3 moiety at its 3-position.