Synthesis, structural investigations, and anti-cancer activity of new methyl indole-3-carboxylate derivatives

Two new methyl indole-3-carboxylate derivatives: methyl 1-(3′-indolylmethane)-indole-3-carboxylate (1), and methyl 1-(1′-benzenosulfonyl-3′-indolylmethane)-indole-3-carboxylate (2) were synthesized. They are interesting as the analogs of 3,3′-diindolylmethane, which is intensively tested as a potent antitumor agent. Their solid-state structure was characterized using 13C CP/MAS NMR or X-ray diffraction measurements. Molecular modeling was used as a help in the structure elucidation. The solid-state NMR spectroscopy showed only one stable conformer of 1, but the X-ray diffraction results indicate that compound 2 crystallizes in the triclinic space group P−1 with two molecules, A and B, in the asymmetric unit. Both compounds inhibited the growth of melanoma, renal and breast cancers cell lines.