Background: Colorectal cancer is one of the common malignant tumors. Cyanopyridine and aminocyanopyridine having a carbon-nitrogen bond have been shown to have significant anticancer effects. STAT3 is a promising therapeutic target in multiple cancers. However, there are currently no effective STAT3 inhibitors in clinical practice for the treatment of colorectal cancer. Materials and methods: We screened 27 cyanopyridines for their anticancer activity by cell viability. The HCT-116, RKO, and DLD-1 cell lines were used to evaluate the anti-colorectal cancer effect of 3n. Scratch experiments and colony formation assays were used for the assessment of cell migration and proliferation capacity. Phosphorylated STAT3, STAT3, MCL-1, and Survivin levels were assessed by Western blot analysis. Results: In this study, we synthesized 27 cyanopyridines and screened their anticancer activities in three human tumor cells, HCT-116, Hela229, and A375. We found that 2-amino-3-cyanopyridine 3n has better anticancer activity with IC50 values in the low micromolar range. Furthermore, 3n significantly inhibited the migration and colony formation of colorectal cancer cells. Mechanistically, 3n inhibited the expression of STAT3 phosphorylation in a dose- and time-dependent manner. Conclusion: 3n is worth of further investigations toward the discovery of STAT3 inhibitor as a drug candidate for cancer therapy.

A new pyridine-pyrazole N–N ligand has been conveniently synthesized and characterized by ¹H-, ¹³C-NMR, IR spectroscopies, HRMS and X-ray single-crystal crystallography analyses. The ligand adds to palladium(II) under basic conditions to give high yields of an air-stable and water-soluble complex that was fully characterized by NMR and HRMS. The complex was investigated as a catalyst for the Suzuki reaction in aqueous media under microwave irradiation. The compound proved to be an effective catalyst.