Synthesis of isogranulatimide analogues possessing a pyrrole moiety instead of an imidazole heterocycle

An efficient four step synthesis from commercial indoles of isogranulatimide analogues is reported. In the new compounds, the imidazole moiety is replaced by a pyrrole unit, the indole part is substituted or not in 5-position and the nitrogen of the imide moiety bears or not a methyl substituent.