Synthesis and pharmacological evaluation of pyrazine N-acylhydrazone derivatives designed as novel analgesic and anti-inflammatory drug candidates.

In this paper, we report the synthesis and pharmacological evaluation of pyrazine N-acylhydrazone (NAH) derivatives (2a-s) designed as novel analgesic and anti-inflammatory drug candidates. This series was planned by molecular simplification of prototype 1 (LASSBio-1018), previously described as a non-selective cyclooxygenase inhibitor. Derivatives 2a-s were evaluated in several animal models of pain and inflammation, standing-out compound 2o (2-N'-[(E)-(3,4,5-trimethoxyphenyl) methylidene]-2-pyrazinecarbohydrazide; LASSBio-1181), that was also active in a murine model of chronic inflammation (i.e., adjuvant-induced arthritis test in rats) and can be considered a new analgesic and anti-inflammatory lead for drug development.