Palladium nanoparticles for the synthesis of phenanthridinones and benzo[ c ]chromenes via C–H activation reaction

DÍAZ-VÁZQUEZ, EVA D.; CUELLAR, MICAELA A.; HEREDIA, MICAELA D.; BAROLO, SILVIA M.; GONZÁLEZ-BAKKER, ADAY; PADRÓN, JOSÉ M.; BUDÉN, MARÍA E.; MARTÍN, SANDRA E.; UBERMAN, PAULA M.

RSC Advances

Royal Society of Chemistry

Lugar: London; Año: 2024 vol. 14 p. 18703 - 18715

In the present work, derivatives of phenanthridine-6(5H)-ones and benzo[c]chromenes were efficiently prepared through an intramolecular C–H bond functionalization reaction catalyzed by photochemically synthesized Pd-PVP nanoparticles. The heterocycles were obtained via intramolecular arylation of the corresponding N-methyl-N-aryl-2-halobenzamide or aryl-(2-halo)benzyl ethers using K2CO3 as base in a mixture of H2O : DMA as solvent without additives or ligands. High yields of the heterocyclic compounds were achieved (up to 95%) using a moderately low catalyst loading (1–5 mol%) under an air atmosphere at 100 °C. The reaction exhibited very good tolerance to diverse functional groups (OMe, Me, t Bu, Ph, OCF3, CF3, F, Cl, –CN, Naph), and both bromine and iodine substrates showed great reactivity. Finally, the in vitro antiproliferative activity of phenanthridine-6(5H)-ones and benzo[c] chromenes was evaluated against six human solid tumor cell lines. The more active compounds exhibit activity in the low micromolar range. 1-Isopropyl-4-methyl-6H-benzo[c]chromene was identified as the best compound with promising values of activity (GI50 range 3.9–8.6 mM). Thus, the benzochromene core was highlighted as a novel organic building block to prepare potential antitumor agents