Synthesis of 4‑Arylthieno[2,3‑<i>b</i>]pyridines and 4‑Aminothieno[2,3‑<i>b</i>]pyridines via a Regioselective Bromination of Thieno[2,3‑<i>b</i>]pyridine

The first regioselective, mild bromination of thieno­[2,3-<i>b</i>]­pyridine is described herein. The reaction proceeds with selectivity toward the 4-position (87% isolated yield). Subsequent cross-coupling reactions proceed in excellent yields and demonstrate the potential of 4-bromothieno­[2,3-<i>b</i>]­pyridine as a building block for use in drug discovery research

Pyrimidinone Nicotinamide Mimetics as Selective Tankyrase and Wnt Pathway Inhibitors Suitable for in Vivo Pharmacology

The canonical Wnt pathway plays an important role in embryonic development, adult tissue homeostasis, and cancer. Germline mutations of several Wnt pathway components, such as Axin, APC, and ß-catenin, can lead to oncogenesis. Inhibition of the poly­(ADP-ribose) polymerase (PARP) catalytic domain of the tankyrases (TNKS1 and TNKS2) is known to inhibit the Wnt pathway via increased stabilization of Axin. In order to explore the consequences of tankyrase and Wnt pathway inhibition in preclinical models of cancer and its impact on normal tissue, we sought a small molecule inhibitor of TNKS1/2 with suitable physicochemical properties and pharmacokinetics for hypothesis testing in vivo. Starting from a 2-phenyl quinazolinone hit (compound <b>1</b>), we discovered the pyrrolopyrimidinone compound <b>25</b> (AZ6102), which is a potent TNKS1/2 inhibitor that has 100-fold selectivity against other PARP family enzymes and shows 5 nM Wnt pathway inhibition in DLD-1 cells. Moreover, compound <b>25</b> can be formulated well in a clinically relevant intravenous solution at 20 mg/mL, has demonstrated good pharmacokinetics in preclinical species, and shows low Caco2 efflux to avoid possible tumor resistance mechanisms