Design and Synthesis of Substituted Pyridazinone-1-Acetylhydrazones as Novel Phosphodiesterase 4 Inhibitors

Abstract

A series of novel pyridazin-6-one-1-acetylhydrazone hybrids were rationally designed to inhibit phosphodiesterase 4 (PDE4B). The prepared compounds were evaluated for their in vitro ability to inhibit the PDE4B enzyme; several of these compounds showed moderate activity compared to the reference drug, rolipram. Compounds 6, 12, and 14 emerged as the most potent inhibitors in this series. The [3-(4-methoxyphenyl)-6-oxo-5,6-dihydro-4H-pyridazin-1-yl]acetic acid [1-(3,4,5-trimethoxyphenyl)ethylidene]hydrazide (12) showed an IC50 value of 13 μM against PDE4B. Docking of 6, 12, and 14 into the active site of PDE4B illustrates their possible binding mode and provides insights for further optimization of this drug scaffold.

Keywords: Docking; N-Acylhydrazones; PDE4B inhibitors; Pyridazinones.