Triphenylphosphonium conjugates of 1,2,3-triazolyl nucleoside analogues. Synthesis and cytotoxicity evaluation

Abstract

A series of triphenylphosphonium (TPP) conjugates of 1,2,3-triazolyl analogues of several pyrimidine nucleosides was synthesized and evaluated for the in vitro cytotoxicity against human cancer cell lines M-HeLa, MCF-7, PANC-1, PC-3, DU145, SKOV-3, A275, and normal human cell line WI-38. In these TPP-conjugates triphenylphosphonium cation was attached via a tetramethylene chain to the N-3 atom of the heterocycle moiety (uracil, thymine, quinazoline-2,4-dione), which was coupled with the D-ribofuranosyl-1,2,3-triazol-4-yl fragment via methylene or tetramethylene linker. It was shown for the first time that the conjugation of 1,2,3-triazolyl derivatives of uridine, its analogues featuring quinazoline-2,4-dione fragment as well as uracil and thymine derivatives, having propargyl or a 1,2,3-triazolyl substituent at the N-1 atom, with a TPP-butyl cation endowed some of them with cytotoxic activity against human cancer cells. Among all human cancer cell lines used, DU-145 and A375 cells were the most sensitive to these TPP conjugates. At the same time, all tested compounds did not inhibit growth of normal cells WI-38. Propargyl containig TPP-conjugates of uracil 4f, 4j, and thymine 5f showed the highest cytotoxicity with IC50 values in the low micromolar concentration range. The present findings suggest that TPP-conjugates of uracil and thymine derivatives would be promising for further development as an anticancer agent.