Variation of Skeletons of Antitumor Antibiotics. II. Synthesis of Naphtho-[2, 3-g] quinolines and Naphtho [2, 3-g] quinoxalines

Abstract

As the initial study of variations of skeletons of antitumor antibiotics, simple synthesis of naphtho [2, 3-g] quinolines (IIIa, b, VIII) and naphtho [2, 3-g] quinoxalines (XIIIa, b), which are novel heterocyclic ring systems, was carried out by Diels-Alder reaction of 1, 2-dimethylenecyclohexane with quinoline-5, 8-diones (Ia-c) or quinoxaline-5, 8-diones (IIa, b). Air oxidation of these Diels-Alder adducts gave tetrahydro naphtho [2, 3-g] quinolines (IVa, b, IX) and tetrahydronaphtho [2, 3-g] quinoxalines (XVa, b). The Diels-Alder adducts and aromatized compounds were converted into the corresponding diacetoxynaphtho [2, 3-g] quinolines (VI, VII, X) and diacetoxynaphtho [2, 3-g] quinoxalines (XVII, XVIII).