Synthesis of 4,5-Disubstituted Benzo[c][2,7]naphthyridines by Combined Metalation-Palladium-Catalysed Cross-Coupling Strategies. Preparation of 8h-Pyrido[4,3,2-<i>mn</i>]acridone as a Model of Cystodytin Alkaloids
Abstract A short and efficient synthesis of 8H-pyrido[4,3,2-mn]acridone is described. The strategy involves the preparation of 4-chloro-5-methylbenzo[c][2,7]naphtyridine, as key intermediate, by metalation and Palladium catalyzed cross-coupling reaction. A second cross-coupling reaction and subsequent oxydation by SeO2 led to the title compound.
An efficient, four-step synthesis of the pyrido [2,3,4-kl]acridin-4-one system is described, using a Suzuki coupling of a 4-iodoquinoline and a oxidative demethylation of a dimethoxyquinoline containing an anilino unit with cobalt trifluoride as the key steps. (C) 2003 Elsevier Ltd. All rights reserved.