Synthesis and in vitro antitumor activity of 3(4)-alkyl-substituted [1,2,4]triazolo[1,5-a]pyrimidin-7-amines

Abstract

A series of [1,2,4]triazolo[1,5-a]pyrimidin-7-amines was synthesized by cyclocondensation of 5-aminotriazoles with morpholinoacrylonitrile derivatives, and alkylation of the products was studied. The alkylation gave two regioisomers, the ratio of which depended on the substituents in the azole and pyrimidine moieties of the heterocyclic system. The new 3(4)-alkyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-amines were tested for the cytotoxic activity against the following human cells: fetal lung (Wi-38), rhabdomyosarcoma (Rd), colorectal adenocarcinoma (CaCo-2), and bladder carcinoma (T-24) cells. The results of the study showed that compound 8 characterized by IC₅₀ < 60 µmol L⁻¹ suppresses the growth of tumor cells. For the lead compound 8, the main putative mechanism of action was studied and found to consist in the cytostatic effect that slows down DNA replication and neoplastic cell division activity without triggering apoptotic mechanisms.