The acridone alkaloid acronycine (1), which was first isolated from Acronychia baueri SCHOTT (Rutaceae) in 1948, was later found to be a potent anticancer agent. [1][2][3][4][5] It is of interest because of its activity against a broad spectrum of solid tumors, including numerous sarcomas, myelomas, carcinomas, and melanomas.2-6) Nevertheless, its low water-solubility and moderate potency have severely hampered its clinical trials, which have given so far only poor results.7) Consequently, the development of structural analogues possessing a basic nitrogen atom able to give water-soluble salts seems highly desirable. 8,9) The replacement of the dimethylpyran D ring of acronycine by a pyridine unit, present in numerous tetracyclic antitumor drugs including the linear ellipticines [10][11][12] and olivacines, [13][14][15] and their angular 7H-and 11H-pyridocarbazoles counterparts, [16][17][18][19] appeared to us an attractive way to look for new anticancer candidates. In addition, this approach was consistent with the antitumor activities of several recently described benzophenanthrolinones related to amsacrine.
20)This paper deals with the synthesis and cytotoxic properties of 12H-benzo[b] [1,7] and [1,10]phenanthrolinones related to acronycine, and also to 6-demethoxyacronycine (2) and 11-aminoacronycine (3), which were shown to exhibit cytotoxic activities within the same range of magnitude as acronycine itself.
9,21)Chemistry The key-step of our approach was an Ullmann condensation 22) of either 2-bromobenzoic acid (4) or 2-chloro-3-nitrobenzoic acid (5) with suitable aminoquinolines 6-8, to afford the carboxylic phenylquinolylamines 9-13. In contrast, all attempts towards the reduction of the nitro group of 15 failed, most probably due to the almost complete insolubility of this compound in usual organic solvents.Pharmacology The study of the biological properties of the new benzophenanthrolin-7-one derivatives was carried out in vitro on L1210 murine leukemia cell line. The results (IC 50 ) are reported in Condensation of either 2-bromobenzoic acid (4) or 2-chloro-3-nitrobenzoic acid (5)