title: Synthesis and antitumor evaluation of new thiazolo[5,4-b]quinoline derivatives.
abstract: A new synthesis of 9-hydroxy- and 9-(alkylamino)thiazolo[5,4-b]quinolines by cyclization of 4-(ethoxycarbonyl)-5-(arylamino)thiazoles and 5-(arylamino)-4-carbamoylthiazoles, respectively, is described. In vitro cytotoxicity of a large number of derivatives of these compounds has been tested against several cell lines. The highest activities observed are associated with the presence of a 2-[[(N,N-diethylamino)ethyl]amino] substituent at C-2 and a fluorine atom at the C-7 position of the tricyclic planar heteroaromatic framework. Three structural features seem to be essential for antitumor activities: a positive charge density at carbon C-7, a side chain at position C-2 or C-9 of the thiazoloquinoline skeleton with two basic nitrogens and a pKa value of 7.5-10 in the most basic center, and a conformational flexibility of this basic side chain. These structural requirements must be simultaneously satisfied in order to ensure a significant antitumor activity.
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Alvarez-Ibarra
authors.forename: R
authors.initials: R
authors.lastname: Fernández-Granda
authors.forename: M L
authors.initials: ML
authors.lastname: Quiroga
authors.forename: A
authors.initials: A
authors.lastname: Carbonell
authors.forename: F
authors.initials: F
authors.lastname: Cárdenas
authors.forename: E
authors.initials: E
authors.lastname: Giralt
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D015394:Molecular Structure; D011804:Quinolines / Q000138:chemical synthesis* / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D011804:Quinolines; D013844:Thiazoles