Synthesis and cytotoxicity of potential anticancer derivatives of pyrazolo[3,4,5-kl]acridine and indolo[2,3-a]acridine

Pyrazolo[3,4,5-kl] acridines were prepared by reaction of ethyl 1,9-dioxo-1,2,3,4,9,10-hexahydroacridine-4-carboxylate (4) with hydrazine and its methyl and 2-(dimethylamino)ethyl derivatives, followed by aromatization of the intermediate products with 1,4-benzoquinone. Conversion of the ester function to a carboxamide was also carried out and N-(2-(dimethylamino)ethyl)-1-(2-(dimethylamino)ethyl)-1,2-dihydropyrazolo[3,4,5-kl]acridine-5-carboxamide (13c) was appreciably cytotoxic in a panel of cell lines. Reaction of 4 with 4-methoxyphenylhydrazine gave instead a novel indolo[2,3-a]acridine derivative. (C) 2002 Elsevier Science Ltd. All rights reserved.