Synthesis and Cytotoxic Activity of New Substituted Pyrazolo[3,4-b]pyridine Derivatives and Their Acyclic Nucleoside Analogs

As an important strategy, including incorporation of more than active core in one molecule, for finding potent candidates against cancer cells, a number of functionalized pyrazolopyridin derivatives linked to oxadiazole, dioxolane, acyclic sugar and fluorene ring systems, were synthesized through heterocyclization reactions. The derived sugar hydrazone and the corresponding acyclic C-nucleoside analog in addition to acyclic N-nucleoside were also prepared. The behavior of the afforded compounds as possible cytotoxic agents against human HTC116 and MCF7 cancer cells was investigated and the results showed that compounds 11-13 showed the highest activities against the two cancer cells. Other compounds revealed a type of selectivity toward one cancer cell while the activity was relatively lost against the other cancer cell line.