Synthesis and evaluation of the anti-proliferative activity of diaryl-3-pyrrolin-2-ones and fused analogs.

Analogs containing a central 3-pyrrolin-2-one core with different methoxyphenyl and/or indole substituents were prepared and tested for anti-proliferative activity in U-937 cells. The most efficacious analogs were non-rigid, (non-fused) contained methoxyaryl groups located at the 4-position, and contained either methoxyaryl or indole groups located at the 3-position. Both the number of methoxy groups contained in the substituents and the particular location of the indole rings with respect to the lactam carbonyl had significant affects on anti-proliferative activity. This work provides a framework to better understand structure-activity relationships for inducing anti-proliferative activity in diaryl heterocyclic scaffolds.

Preparation of dibenzo[e,g]isoindol-1-ones via Scholl-type oxidative cyclization reactions.

A flexible synthesis of dibenzo[e,g]isoindol-1-ones has been developed. Dibenzo[e,g]isoindol-1-ones represent simplified benzenoid analogues of biological indolo[2,3-a]pyrrolo[3,4-c]carbazol-5-ones (indolocarbazoles), compounds that have demonstrated a wide range of biological activity. The synthesis of the title compounds involved tetramic acid sulfonates. Different aryl groups were introduced at C4 of the heterocyclic ring via Suzuki-Miyaura cross-coupling reactions. Finally, mild Scholl-type oxidative cyclizations mediated by phenyliodine(III) bis(trifluoroacetate) (PIFA) converted some of the latter compounds into the corresponding dibenzo[e,g]isoindol-1-ones. A systematic study of the oxidative cyclization revealed the following reactivity trend: 3,4-dimethoxyphenyl ≫ 3-methoxyphenyl > 3,4,5-trimethoxyphenyl > 4-methoxyphenyl ≈ phenyl. Overall, the oxidative cyclization required at least two methoxy groups distributed in the aromatic rings, at least one of which had to be located para to the site of the cyclization.