A practical regioselective synthesis of alkylthio- or arylthioindoles without the use of smelly compounds such as thiols.

A convenient method for the synthesis of 3-methylthioindoles has been established which does not use smelly compounds such as thiol derivatives. The method, which introduces an alkyl- or arylthio-group into the C3-position of the indole skeleton, was extended to the direct introduction of a methylthio or bromo group at the C2-position using 3-methylthioindoles.