Abstract The title compound 17 was prepared in good yield starting from 5, 6, 7, 8-tetrahydro- l-naphthol (9) by an advantageous synthesis route consisting of eight steps, as indicated in Scheme 2. Demethylation by reflux heating with anhydrous aluminium chloride in dry benzene furnished 4, 9-dihydroxy-and 4, 9-dioxo-5, 6, 7, 8-tetrahydro-1H-benz [f] indoles (compounds 18 and 19, respectively). All new products were identified on the basis of ...