Process for the preparation of naphthacenetetraone derivatives

摘要

For the preparation of a compound of the formula IV, <IMAGE> an appropriate compound of the formula III <IMAGE> is subjected to a Diels-Alder condensation with an appropriate compound of the formula <IMAGE> in which R8 has the meaning given in Patent Claim 1. For the preparation of a compound of the formula VII, <IMAGE> the compound of the formula IV obtained is treated either with strong acid in a water-miscible organic solvent or in sequence first with a proton acceptor or proton donor and then with mineral acid or mild base in a water-miscible organic solvent. The compounds obtained offer a novel route for the preparation of antibiotics, in particular of analogous compounds of (+/-)-deoxydaunomycinone having antineoplastic action.