h i g h l i g h t s " Four main metabolites of quinocetone were conveniently synthesized and fully characterized. " Theoretical N–O bond dissociation enthalpies and the octanol-water partition coefficient (K ow) were estimated. " The results from MTT assay have showed that quinocetone and its metabolites have cytotoxicity. a b s t r a c t Quinocetone (3-methyl-2-quinoxalinbenzenevinylketo-1,4-dioxide; QCT) is a new promising antimicro-bial 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 syn-thesis, 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-resolu-tion mass spectroscopy. The theoretical NAO bond dissociation enthalpies (BDEs) and octanol–water par-tition coefficient (K ow) 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 NAO BDEs. Ó 2012 Elsevier B.V. All rights reserved.