Pyrazolyl‐Benzoxazinone Derivatives as Dual Hsp Inhibitors in Human Breast Cancer

Abstract Heat Shock Proteins (Hsps) play major role on the onset of several cancers. Metabolic rates of cancer cells are higher compared to that of untransformed cells. This accelerated rate force functional substrate proteins to fold faster than normal folding rate. Although, the process leads cell cycle halting and eventually induces apoptosis, Hsps help cell survival and inhibit apoptosis and fold substrate proteins especially signaling proteins. When cancer cells accelerate the metabolism for invasion and metastasis, substrate proteins must fold to their native state rapidly. Since, functional forms of the proteins must be folded properly, cancer cells overexpress Hsps to fold substrate proteins and avoid apoptosis. Hsp90 and Hsp70 play key role in these processes. Inhibition of either Hsp90 or Hsp70 display complementary function. Therefore, dual inhibition of Hsp70 and Hsp90 potentially provides anticancer affect. In silico studies showed that pyrazolyl‐benzoxazine derivatives display binding activity for both Hsps. For this purpose, pyrazole‐3‐carbonyl chloride were converted to pyrazolyl‐benzoxazine derivatives via reactions of anthranilic acids in good yields (68–83 %). The structures of the newly synthesized compounds were elucidated by IR‐NMR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. Binding of the compounds inhibit function of Hsps and cause cytotoxic effect over MCF‐7 cells. The compounds display potential anticancer effects.