Pyridonecarboxylic acids as antibacterial agents. 4. Synthesis and antibacterial activity of 7-(3-amino-1-pyrrolidinyl)-1-ethyl-6-fluoro-1,4 -dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid and its analogues

The title compounds (28-56) with an amino- and/or hydroxy-substituted cyclic amino group at C-7 were prepared with 1-substituted 7-chloro-, 7-(ethylsulfonyl)-, and 7-(tosyloxy)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3- carboxylic acids and their ethyl esters (3-7) with cyclic amines such as 3-aminopyrrolidine. The N-1 substituent includes ethyl, vinyl, and 2-fluoroethyl groups. As a result of in vitro and in vivo antibacterial screenings, three compounds, 1-ethyl- and 1-vinyl-7-(3-amino-1-pyrrolidinyl)-6-fluoro- 1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids (33a and 33b) and 1-vinyl-7-[3-(methylamino)-1-pyrrolidinyl] analogue 34b, were found to be more active than enoxacin (2) and to be worthy of further biological study. Structure-activity relationships are discussed.     

Synthesis of some derivatives of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-1-yl)-3-quino linecarbo xylic acid (norfloxacin) as potential antibacterial agents

Twelve new fluoroquinolones, structurally related to norfloxacin, have been synthesized in order to investigate the effect of substituents at the secondary nitrogen of the piperazine ring on antimicrobial activity. The new substances (carbamates, isoureas, guanidines, ureas and cyanamides) tested on a variety of gram-positive and gram-negative organisms showed lower activity than the model compound.     

Fluoronaphthyridines as antibacterial agents. 4. Synthesis and structure-activity relationships of 5-substituted-6-fluoro-7-(cycloalkylamino)-1,4-dihydro-4-oxo-1,8- naphthyridine-3-carboxylic acids.

A series of 5-substituted-6-fluoro-7-(cycloalkylamino)-1,4-dihydro-4-oxo-1,8- naphthyridine-3-carboxylic acids have been prepared and tested for their in vitro and in vivo antibacterial activities. The 5-methyl group gave better in vitro activity with the 1-cyclopropyl appendage, but poorer activity with the 1-tert-butyl moiety. With the 1-(2,4-difluorophenyl) substitution, the influence of the 7-cycloalkylamino group was determinant: a (3S)-3-amino-pyrrolidine was shown to enhance greatly the in vitro and in vivo activity of the 5-methyl derivative. Compound 33 (BMY 43748) was selected as a promising candidate for an improved therapeutic agent.     

吡酮酸类抗菌药物的研究Ⅷ.1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其类似物的合成和构效关系

为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。     

Pyridonecarboxylic acids as antibacterial agents. 9. Synthesis and antibacterial activity of 1-substituted 6-fluoro-1,4-dihydro-4-oxo-7-(4-pyridyl)-1,8-naphthyridine-3- carboxylic acids

The title compounds (7a-e) with ethyl, 2-fluoroethyl, 2-hydroxyethyl, vinyl, or cyclopropyl groups, respectively, at C-1 were prepared by the method involving the Balz-Schiemann reaction of 2-(4-pyridyl)pyridine- and 7-(4-pyridyl)-1,8-naphthyridinediazonium tetrafluoroborates (15 and 27). The 1-ethyl, 1-(2-fluoroethyl), and 1-vinyl derivatives showed in vitro activities as potent as the corresponding 7-(1-piperazinyl) analogues against Staphylococcus aureus 209P JC-1 and Escherichia coli NIHJ JC-2 but were less active against Pseudomonas aeruginosa 12. Among the 7-(4-pyridyl) derivatives having the different C-1 substituent, 1-cyclopropyl derivative 7e was found to be the most active. In vivo efficacy of 7e was superior to that of enoxacin against experimental infections due to S. aureus 50774. Some aspects of structure-activity relationships associated with the C-1, C-6, and C-7 substituents were discussed.     

1-烷基-6-氟-1,4-二氢-7-(4-酰基-1-哌嗪基)-4-氧代喹啉-3-羧酸类似物的合成及其抗菌活性

目的 设计合成具有广谱抗菌活性的含氟喹诺酮类化合物。方法 利用吡酮酸7位哌嗪基4位氮上存在的活性氢为反应修饰基点，与磺酰氯，酰氯，氯甲酸酯进行Schotten-Baumann酰基化反应设计合成一系列含有磺酰基、酰基和烷氧羰基类氟喹诺酮类似物。结果 合成了20个含有磺酰基、酰基和氧羰基的氟喹诺酮类似物，利用元素分析、核磁共振进行了结构确认。结论 合成了16个未见报道的新化合物，初步体外活性测试结果表明，其中的4个化合物有较高的生物活性。     

Synthesis and antibacterial activity of 1-(substituted pyrrolyl)-7-(substituted amino)-6-fluoro-1,4-dihydro-4-oxo-3- quinolinecarboxylic acids.

Seventeen quinolone compounds characterized by having a fluorine atom at the 6-position, a substituted amino at the 7-position, and a substituted pyrrolyl at the 1-position were synthesized for the first time. The in vitro antibacterial activities of these compounds against Escherichia coli and Staphylococcus aureus were tested. Among these agents obtained, compound 24 showed significantly enhanced activity against S. aureus. The results indicate that there is much room for modifications at the N-1 position.     

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 1

In an attempt to search for clinically useful antitumor agents, we have discovered that a series of 1,7-disubstituted-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids possessed moderate cytotoxic activity. We investigated the structure-activity relationships in this series of compounds by changing N-1 and C-7 positions and the core ring structure itself and evaluated the synthesized compounds against several murine and human tumor cell lines. These modifications led us to the following findings. (1) The 2-thiazolyl group at the N-1 position of the naphthyridine structure is the best substituent for antitumor activity. (2) Regarding core ring structure, the naphthyridine derivative is the most active followed by pyridopyrimidine analogue. (3) At the C-7 position, aminopyrrolidine derivatives are more effective than other amines or thioether derivatives. Finally, the trans-3-amino-4-methoxypyrrolidinyl derivative (43j) and the 3-amino-3-methylpyrrolidinyl derivative (43f) as well as 3-aminopyrrolidinyl derivative (AT-3639, 1) were determined to be effective in in vitro and in vivo antitumor assays, and their activity was comparable to that of etoposide.     

Research on antibacterial and antifungal agents. VII. Synthesis of (1-pyrryl)methylquinolines acids

Some (1-pyrryl)methyl derivatives of 1-ethyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid were synthetized by the standard procedure involving Gould-Jacobs and Lappin reactions. The above derivatives were tested microbiologically as nalidixic acid analogs and compared with some clinically useful 4-oxopyridine-3-carboxylic acids (nalidixic acid, pipemidic acid, norfloxacin, enoxacin and ciprofloxacin). Their antibacterial activities were very weak.     

Inhibition of HSV-1 replication and HSV DNA polymerase by the chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid and its aglycone

We describe in this paper that the synthetic chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid (compound A) and its free aglycogene base (compound B) inhibit, with low cytotoxicity, the replication of herpes simplex virus type 1 and 2 (HSV-1 and HSV-2). Compound A inhibited HSV-1 replication in Vero cells with an EC(50) of 1.3 and 1.4 microM for an acyclovir (ACV)-sensitive strain and an ACV-resistant strain of this virus, respectively. Additionally, it inhibited HSV-2 replication with an EC(50) of 1.1 microM. Compound B also inhibited the ACV-sensitive and -resistant HSV-1 strains, and HSV-2 at EC(50) values of 1.7, 1.9 and 1.6 microM, respectively. Time-of-addition assays, performed with compound A, suggested that this molecule at an early time point of the HSV replication cycle. Kinetic assays demonstrated that compounds A and B inhibit the HSV DNA polymerase activity in a noncompetitive fashion, with a K(i) equal to 0.1 and 0.2 microM, respectively. Taken together, our results suggest that compounds A and B represent promising lead molecules for further anti-HSV drug design.     

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

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.     

吡酮酸类抗茵药物的研究XVI．6-氟-1-（2-氟-5-吡啶基）-7-（1一哌嗪基）-1，4-二氢-4-氧代喹啉-3-羧酸及其类似物的合成与抗茵作用

合成了14个6-氟-1-(2-氟-5-吡啶基)-5．7．8-不同取代-1．4-二氢-4-氧代喹啉-3-羧酸及其类似物．测定了它们对14株革兰氏阳性和革兰氏阴性细菌的MIC值．并与环丙沙星对照。结果表明,这些化合物的抗菌活性均很弱。     

7-(吡啶-N-氧-2-巯基)-1-(2-氟乙基)-6,8-二氟-1,4-二氢-4-氧喹啉-3-羧酸的合成及抗菌活性

目的：根据喹诺酮类抗菌药和抗菌防腐剂２ － 巯基吡啶－ Ｎ－ 氧化物的抗菌作用原理设计、合成化合物７ － （ 吡啶－ Ｎ－ 氧－ ２ － 巯基） － １ － （２ － 氟乙基） － ６ ,８ － 二氟－ １ ,４ － 二氢－ ４ － 氧喹啉－ ３ － 羧酸,对其抗菌活性进行了研究。方法：合成此化合物,并研究其体外抗菌活性。结果：该化合物的体外抗菌活性优于国外近期上市的喹诺酮类抗菌药———氟罗沙星。结论：此类化合物有进一步研究的价值,为进一步研究喹诺酮类抗菌药提供了一个方向。     

7-(吡啶-N-氧-2-巯基)-1-(2-氟乙基)-6,8-二氟-1,4-二氢-4-氧喹啉-3-羧酸的合成及抗菌活性

目的;根据喹诺酮类抗菌药和抗菌防腐剂２－巯基吡啶－Ｎ－氧化物的抗菌作用原理设计,合成化合物７－（吡啶－Ｎ－氧－２－巯基）－１－（２－氟乙基）－６,８－二氟－１,４－二氢－４－氧喹啉－３－羧酸,对其抗菌活性进行了研究。方法;合成此化合物,并研究其体外抗菌活性。     

Asymmetric synthesis and properties of the enantiomers of the antibacterial agent 7-(3-aminopyrrolidin-1-yl)-1-(2,4-difluorophenyl)-1,4-dihydro-6- fluoro-4-oxo-1,8-naphthyridine-3-carboxylic acid hydrochloride

Compound 1 [7-(3-aminopyrrolidin-1-yl)-1-(2,4-difluorophenyl)-1,4-dihydro-6-f luoro-4-oxo-1,8-naphthyridine-3-carboxylic acid hydrochloride] is a potent member of the quinolonecarboxylic acid class of antibacterial agents and is currently undergoing clinical evaluation. We have developed efficient asymmetric syntheses of the enantiomers of this agent. The S-(+) enantiomer 1a is 1-2 log2 dilutions more active than the R-(-) enantiomer 1b against aerobic bacteria and 1-2 or more log2 dilutions more active against anaerobic bacteria in vitro. The enantiomer 1a shows significantly better in vivo activity in a Pseudomonas aeruginosa mouse protection model compared to racemic 1. Coupled with the improved solubility profile of 1a relative to racemic material, these features may be of practical significance from a clinical standpoint.     

Synthesis and antibacterial activity of 2-substituted 6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids.

A series of 2-substituted 6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids was prepared and evaluated for antibacterial activity. The 6-fluoro-2-methyl-1-prenyl-1,4-dihydro-7-(3,5-dimethylpiperazinyl)-4-oxo-3-quinolinecarboxylic acid (14f) exhibited the most potent antibacterial activity against gram-positive bacteria among the total 32 derivatives. The synthetic strategies involve the use of well known keto ester condensation of benzoyl chloride and reductive cyclization of intermediates (4a-d) to afford 4-hydroxy-1,2-dihydro-2-oxo-quinoline derivatives (5a,b) or 1-hydroxy-1,4-dihydro-4-oxo-quinoline derivatives (6a,b).     

吡酮酸类抗菌药物的研究——Ⅵ.7-氯-6-氟-1-乙基-1,4-二氢-4-氧吡啶(2,3-c)并哒嗪-3-羧酸及其衍生物的合成与抗菌活性

由2,6-二氯-5-氟-3-氰基吡啶出发,经氰基水解、酰氯化、与重氮乙酸乙酯缩合、重氮基还原、环化五步反应合成了一个新的杂环体系,即取代的吡啶(2,3-c)并哒嗪Ⅵ。由Ⅵ为原料经不同途径制得21个新衍生物,其中10个游离酸进行了体外抗菌活性筛选。对金葡-15、大肠-1515、绿脓-29的MIC(μg/ml),除化合物Xa和Xb对大肠-1515为50外,其余均大于100。     

Gyrase inhibitors. 3. Synthesis and reactions of 1,4-dihydro-4-oxo-(1)benzothieno(3,2-b)pyridin-3-carboxylic acid esters

The title compound 4a is synthesized from potassium 3-aminobenzo[b]thiophene-2-carboxylate (1) by Gould-Jacobs reaction. Compound 4a reacts with alkyl halides and sodium hydride in DMF to yield the N-alkylpyridones 5a-c as well as the 4-alkoxypyridines 6a-c; with phosphoryl chloride the 4-chloropyridine 7a is obtained. The carboxylic acids 4b, 5d, 5e, 6d and 7b are received by alkaline saponification of the esters 4a, 5a-c, 6a-c and 7a. The carbinoles 8 and 9, formed by boranate reduction of the esters 6a and 7a, are transformed to the aldehydes 10 and 11 by activated manganese dioxide oxidation. The aldoxime 12 from the carbaldehyde 11 is dehydrated to yield the nitrile 13. The carbaldehyde 11 reacts with methyl beta-aminocrotonate to yield the 1,4-dihydropyridine (DHP) 14, which is dehydrogenated to give the 3,4'-bipyridine 15. The pyridone 4a reacts with tosylisocyanate to yield the 4-tosylaminopyridine 16a. The antibacterial activity of the carboxylic acids 4b, 5d, 5e and 6d is proved. The growth of Escherichia coli and Bacillus megaterium is inhibited by 5d in the same range as nalidixic acid does.