Synthesis of Bay-Region Diol Epoxides and Other Derivatives of Benzo[h]Quinoline

The azaphenanthrenes, benzo[f]quinoline (BfQ, 1) and benzo[h]quinoline (BhQ, 2), are environmental contaminants that have been detected in automobile exhaust, urban air particulates, and cigarette smoke.^2-4BfQ and BhQ have been shown to be metabolically activated to products mutagenic to Salmonella typhimurium.^5-8In contrast to BfQ and BhQ, their carbon analogue phenanthrene is nonmutagenic.⁹ In a previous paper,¹⁰ we have described the synthesis of dihydrodiol and diol epoxide derivatives of benzo[f]quinoline. Since we are interested in understanding (i) the mechanism by which the presence and position of aza substitution influence the biological activity of azaphenanthrenes and (ii) the metabolism of these chemicals, we require dihydrodiol and diol epoxide derivatives of benzo[h]quinoline. The present paper describes the synthesis of dihydro diol 3, diol epoxides 4 and 5, and tetrahydro epoxides 6 and 7.