Background: N-substituted 3-amino-1H-indazoles represent an interesting class of biologically
active compounds. Among them, derivatives containing phenylurea moiety are of particular
interest. Such compounds have been found to possess inhibitory activity against cancer cell
growth. Additionally, various oxazoline-containing compounds have also been designed as potential
Objective: The aim of this work was to obtain a new class of N-substituted 3-amino-1H-indazole
derivatives with cytotoxic activity towards cancer cells.
Method: Two series of 1-[1-(4,5-dihydrooxazol-2-yl)-1H-indazol-3-yl]-3-phenylurea and 3-
phenylthiourea derivatives 7-17 and 18-22, respectively, were prepared and screened for their potential
in vitro cytotoxic activities against lung carcinoma LCLC-103H cell line using a crystal
violet microtiter plate assay.
Results: All the urea derivatives, except the compound 8, were inactive at a concentration of 20
μM attainable in cancer cells, while the thiourea derivatives showed a pronounced cancer cell
growth inhibitory effects. The most potent 1-[1-(4,5-dihydrooxazol-2-yl)-1H-indazol-3-yl]-3-ptolylthiourea
(19) exhibited cytotoxicity on the lung cancer LCLC-103H and cervical cancer SISO
cell lines at a concentration of 10 µM. Moreover, compound 19 displayed cytostatic activity
against pancreas cancer DAN-G cell line.
Conclusion: The 1-[1-(4,5-dihydrooxazol-2-yl)-1H-indazol-3-yl]-3-phenylthiourea derivatives described
herein may serve as a useful scaffold for the search for novel anticancer agents.