3-Amino-N-benzyl-6-(4-fluoro-phen-yl)thieno[2,3-b]pyridine-2-carboxamide.

In the title compound, C(21)H(16)FN(3)OS, the thieno[2,3-b]pyridine system forms dihedral angles of 10.57 (12) and 83.87 (5)° with the fluoro-phenyl ring at the 6-position and the phenyl ring of the benzyl group, respectively. In the crystal, mol-ecules are linked by weak N-H⋯N anf N-H⋯O hydrogen bonds and π-π stacking inter-actions involving fluoro-phenyl rings of adjacent mol-ecules, with a centroid-centroid distance of 3.648 (10) Å. In addition, intra-molecular N-H⋯S and N-H⋯O hydrogen bonds contribute to the stability of the mol-ecular conformation.

Novel pyrazolo[3,4-d]pyrimidine derivatives as potential antitumor agents: exploratory synthesis, preliminary structure-activity relationships, and in vitro biological evaluation.

In a cell-based screen of novel anticancer agents, the hit compound 1a which bears a pyrazolo[3,4-d]pyrimidine scaffold exhibited high inhibitory activity against a panel of four different types of tumor cell lines. In particular, the IC50 for A549 cells was 2.24 µM, compared with an IC50 of 9.20 µM for doxorubicin, the positive control. Four synthetic routes of the key intermediate 3 of 1a were explored and 1a was prepared via route D on the gram scale for further research. Two analogs of 1a were synthesized and their preliminary structure-activity relationships were studied. Flow cytometric analysis revealed that compound 1a could significantly induce apoptosis in A549 cells in vitro at low micromolar concentrations. These results suggest that the target compound 1a and its analogs with the pyrazolo[3,4-d]pyrimidine scaffold might potentially constitute a novel class of anticancer agents, which requires further studies.