Regiospecific Synthesis of the Aminoimidazoquinoxaline (IQx) Mutagens from Cooked Foods

Article abstract of DOI:10.1021/jo00031a017

A versatile regiospecific synthesis has been developed to prepare the six dimethyl- and trimethyl-substituted 2-aminoimidazoquinoxaline (IQx) regioisomers 35, 36, 37, 38, 39, and 40 for complete and unambiguous characterization.The key reaction step in the synthetic sequence for these angular tricycles is a photodehydrohalogenative cyclization of suitably substituted pyrazinylimidazolylethylene intermediates derived from common pyrazine and fully functionalized imidazole precursors.The reaction sequence developed allows for versatility in the substitution pattern as well as total regioisomeric control for the synthesis of all possible methyl and polymethyl analogues of IQx.Comparison of the physical properties among the isomeric di- and trimethyl-IQx's has established the value of unambiguous regiospecific synthesis for structural assignments in this food mutagen series.