Convenient synthesis of quinocetone metabolites: Characterization, theoretical investigation, and cytotoxicity study

Quinocetone (3-methyl-2-quinoxalinbenzenevinylketo-1,4-dioxide; QCT) is a new promising antimicrobial growth promoter for quinoxalines. The identification of the major metabolites of QCT has resulted in a number of studies regarding its metabolic pathway. However, little is known about the systematic synthesis, characterization, and simultaneous determination of its metabolites. To obtain system data for the four main metabolites of QCT, a convenient synthesis of these compounds was performed. All synthesized compounds were characterized by infrared spectroscopy, nuclear magnetic resonance, and high-resolution mass spectroscopy. The theoretical NO bond dissociation enthalpies (BDEs) and octanol–water partition coefficient (Kow) were estimated. A cytotoxicity assay for these compounds in hepatocytes isolated from rats was proposed, and the cytotoxicity results were evaluated based on the calculated NO BDEs.