New 1 H-Benzo[ f]indazole-4,9-diones Conjugated with C-Protected Amino Acids and Other Derivatives: Synthesis and in Vitro Antiproliferative Evaluation

Abstract

1 H-Benzo[ f]indazole-4,9-dione derivatives conjugated with C-protected amino acids (glycine, l-alanine, l-phenylalanine and l-glutamic acid) 6a– l were prepared by chemically modifying the prenyl substituent of 3-methyl-7-(4-methylpent-3-enyl)-1 H-benzo[ f]indazole-4,9-dione 2 through epoxidation, degradative oxidation, oxidation and N-acyl condensation reactions. The chemical structures of the synthesized compounds were elucidated by analyzing their IR, ¹H-NMR and ¹³C-NMR spectral data together with elemental analysis for carbon, hydrogen and nitrogen. The preliminary in vitro antiproliferative activity of the synthesized derivatives was evaluated on KATO-III and MCF-7 cell lines using a cell proliferation assay. The majority of the derivatives exhibited significant antiproliferative activity with IC ₅₀ values ranging from 25.5 to 432.5 μM. These results suggest that 1 H-benzo[ f]indazole-4,9-dione derivatives are promising molecules to be researched for developing new anticancer agents.