title: Synthesis and structure-activity relationships of novel 7-substituted 1,4-dihydro-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acids as antitumor agents. Part 2.
abstract: We have previously reported that a series of 7-substituted 6-fluoro-1,4-dihydro-4-oxo-1-(2-thiazolyl)-1,8-naphthyridine-3-carboxylic acids possess moderate cytotoxic activity. In a further attempt to find clinically useful antitumor agents, we investigated the structure-activity relationships (SARs) of a new series of compounds obtained by changing the C-6 position of the fluorine atom in addition to the C-5 and C-7 positions and evaluating their cytotoxic activity against several murine and human tumor cell lines. Our results showed that the 6-unsubstituted 1,8-naphthyridine structure had the most potent cytotoxic activity against murine P388 leukemia twice that of the 6-fluoro analogue. In addition, introduction of an amino group at the C-5 position did not have any substantial effect on the cytotoxic activity, while both the 5-chloro and 5-trifluoromethyl groups decreased the cytotoxic activity by 5- to 10-fold. Moreover, aminopyrrolidine derivatives at the C-7 position showed more potent cytotoxic activity than other amines or carbon derivatives. Among the 7-(3-aminopyrrolidinyl) derivatives, the trans-3-methoxy-4-methylaminopyrrolidinyl derivative (27l) was determined to have potent cytotoxic activity in both in vitro and in vivo assays and high water solubility. Finally, the (S,S)-isomer (AG-7352, 3) of 27l, with a cytotoxic activity against human tumor cell lines more potent than that of etoposide, was selected for further development.
authors.affiliation: Chemistry Research Laboratories, Dainippon Pharmaceutical Co. Ltd., Enoki 33-94, Suita, Osaka 564-0053, Japan. yasunori_tuduki@dainippon-pharm.co.jp
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Tsuzuki
authors.forename: Kyoji
authors.initials: K
authors.lastname: Tomita
authors.forename: Koh-ichiro
authors.initials: K
authors.lastname: Shibamori
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sato
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kashimoto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Chiba
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D051379:Mice; D009287:Naphthyridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D009368:Neoplasm Transplantation; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D014183:Transplantation, Heterologous; D014230:Triazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D009287:Naphthyridines; D013844:Thiazoles; D014230:Triazoles; C485113:vosaroxin