Reaction of Pyrrole Anions with Carbon Disulfide. Synthesis of Pyrrole-3-carbodithioates

2,5-Disubstituted pyrroles react with carbon disulfide in the system KOH–DMSO with selective formation of pyrrole-3-carbodithioate anions from which pyrrole-3-carbodithioates were prepared by ethylation in 36–61% yield. From 2-methyl-5-phenyl(2-furyl- or 2-thienyl)pyrroles only pyrrole-3-carbodithioates are formed, with no isomeric pyrrole-4-carbodithioates being present. The reaction direction depends on pyrrole ring substitution: unsubstituted pyrrole selectively forms pyrrole-1-carbodithioate, whereas 2-methyl-, 2,3- and 2,4-dimethylpyrroles give exclusively pyrrole-2-carbodithioates under the same conditions.