Synthesis and antibacterial activity of various substituted oxadiazole derivatives

Some new 2-(2-(4(4-substitutedbenzoyl-2-methylphenoxy)acetyl)-N-(2-substitutedphenyl) hydrazinecarbothioamides (4a-4j) and (4-((5-(2-substitutedphenylamino)-1,3,4-oxadiazol-2-yl)methoxy)-3-substitutedphenyl)(phenyl)methanones (5a-5j) have been synthesized from 2-(4-(3-substitutedbenzoyl)-2-methylphenoxy)acetohydrazides (3a, 3b). These newly synthesized compounds (4a-4j and 5a-5j) were characterized by elemental and spectral (IR, (1)H-NMR and MS) analysis. All the synthesized compounds have been screened for their antibacterial activity against both types of Gram negative and Gram positive bacteria. The most potent antibacterial compound of this series was compound 5i which has the low MIC 3.75-0.9375 μg/mL value. Both minimal inhibitory concentration (MIC) and inhibition zones were determined in order to monitor the efficacy of the synthesized compounds. Certain compounds inhibit bacterial growth with low MIC (μg/mL) value.     

Oxadiazole-carbonylaminothioureas as SIRT1 and SIRT2 inhibitors

A new inhibitor for human sirtuin type proteins 1 and 2 (SIRT1 and SIRT2) was discovered through virtual database screening in search of new scaffolds. A series of compounds was synthesized based on the hit compound (3-[[3-(4-tert-butylphenyl)1,2,4-oxadiazole-5-carbonyl]amino]-1-[3-(trifluoromethyl)phenyl]thiourea). The most potent compound in the series was nearly as potent as the reference compound (6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide).     

Synthesis and antimicrobial activity of 4-carbethoxymethyl-2-[(alpha-haloacyl)amino] thiazoles and 5-nonsubstituted/substituted 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones

4-Carbethoxymethyl-2-[(chloroacetyl/alpha-chloropropionyl/al pha- bromobutyryl/alpha-chloro-(alpha-phenylacetyl)amino]thiazoles (I-IV) were synthesized by reacting 4-carbethoxymethyl-2-aminothiazole with chloroacetyl chloride, alpha-chloropropionyl chloride, alpha-bromobutyryl bromide and alpha-chloro-alpha-phenylacetyl chloride, respectively. Furthermore, I-IV were refluxed with ammonium thiocyanate to give 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones (V-VIII). V was refluxed with various aromatic aldehydes to give 5-arylidene-2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-t hiazolidinones (IX-XIV). The structures of synthesized compounds were confirmed by elemental analyses, hydrolysis, UV, IR, 1H-NMR and EI mass spectral data. The antimicrobial activities of the compounds were assessed by microbroth dilution technique using Mueller-Hinton broth and Mueller-Hinton Agar. In this study, Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis and Candida albicans ATCC 10231 were used as test microorganisms. Among the tested compounds, XI and XIV showed activity against S. aureus (MIC: 78 micrograms/ml, 1.6 micrograms/ml), whereas compound V had an activity against S. flexneri (MIC: 39 micrograms/ml) and compound I against C. albicans (MIC: 125 (micrograms/ml). Compounds I, IV-XIV were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. Only compounds I and XIV showed 86% and 67% inhibition in the primary screen.     

Studies on isoquinoline derivatives. IV. Synthesis and evaluation of the antimicrobial and antifungal activities of N2-arylidene-substituted 3-carbazoyl-isoquinolines

2,4-Dimethyl-1-oxo-1,2-dihydro-3-carbazoyl-isoquinoline (II), 1-chloro-, 1-methoxy-3-carbazoyl-4-methylisoquinoline (VI, X) and a series of their hydrazonic derivatives have been synthesized and tested in vitro for antibacterial and antifungal activities. 1-(1-Chloro-4-methyl-3-isoquinolinoyl)-2-(5-nitro-2-furfurylide ne) hydrazine (VII h) proved to be the most effective in the series (MIC 0.78 micrograms/ml) and was more potent than furazolidone against several strains of S.aureus; the same compound also showed a moderate antifungal activity.     

Synthesis and evaluation of antibacterial activity of some 2-[[alpha-(4-substituted benzoyloxy)-alpha-phenylacetyl or methylacetyl]amino]-5-(4-methoxyphenyl)- 1,3,4-oxadiazoles

In this study, a new series of 1-[[alpha-(4-substitutedbenzoyloxy)-alpha-phenylacetyl or methylacetyl]amino]-5-(4-methoxyphenyl)-1,3,4-oxadiazoles were obtained by condensation of 2-[(alpha-chloro-alpha-phenylacetyl or alpha-bromopropionyl)amino]-5-(4-methoxyphenyl)1,3,4-oxadiazoles with sodium salts of 4-substituted benzoic acids. Structures of the compounds were assigned on the basis of spectral data (UV, IR, 1H NMR, El MS) and elemental analyses. The antibacterial activities of the novel compounds against Staphylococcus aureus ATCC 6538. Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri and Proteus mirabilis and antifungal activity against Candida albicans ATCC 10231 were tested using disk diffusion method. Compounds 4a, 4d and 4g were found to be active against S. aureus ATCC 6538 (MIC, 78, 39 and 78 microg ml(-1), respectively) and compound 4e against S. epidermidis ATCC 12228 (MIC, 156 microg ml(-1)).     

Structure activity relationship of ar-turmerone analogues

For the analysis of structure activity relationship of ar-turmerone analogues, the compounds containing the various substituents on the phenyl ring and 1(or 2)-naphthyl group in the place of phenyl of ar-turmerone were prepared and tested their cytotoxicity against HL-60, K-562, and L1210 leukemia cellsin vitro. The substituents at para position are methoxy, phenoxy, methyl, trifluoromethyl, fluoro, and chloro. Atmeta position methoxy, methyl, trifluoromethyl, or chloro groups and atortho position methoxy or chloro group were introduced. Against HL-60 and K-562 cells, ED₅₀ values of the analogues are ranged from 0.8 to 30.0 μg/ml. Against L1210 cell, these are located more than 20.0 μg/ml. However, 5-carboethoxy-2-methyl-6-(1-naphthyl)-2-octen-4-one (5n) possesses ED50 valuses 0.8, 2.1, 6.5 μg/ml against HL-60, K-562, L1210 cells, respectively. The electronic nature of the subsituents on phenyl ring of ar-turmerone dose not affect the biological activity. Therefore the flat structure of aromatic portion of ar-turmerone analogues is the more important factor for their activity rather than its electronic nature. The potentiation of the cytotoxicity with the enlargement of aromatic ring region also supports the importance of the plane structure of this area. The restriction of the single bond rotation between C-6 and aromatic ring through the introduction of substituents at theortho position of phenyl ring and the increment of size of alkyl group at C-6 position enhances the activity. Therefore the effective conformation should be the one having the orthogonal arrangement between the aromatic ring and the side chain.     

7-chloro-3-(substituted benzylidene/phenyl ethylidene amino)-2-phenylquinazolin-4(3H)-ones: synthesis, antimicrobial and antitubercular evaluation

In this study, a series of 7-chloro-3-(substituted benzylidene/phenyl ethylidene amino)-2-phenyl quinazolin-4(3H)-ones (1–10) were prepared and evaluated for antitubercular activity against Mycobacterium tuberculosis (MTB). The antitubercular screening results indicated that 7-chloro-3-(4-(dimethylamino)benzylidene amino)-2-phenylquinazolin-4(3H)-one (10) was the most potent one (MIC?=?0.78?×?10^?3?μM) and exhibited activity equivalent to the standard compound isoniazid (MIC?=?0.80?×?10^?3?μM). Further, the synthesized compounds were tested for their antibacterial activity against Gram positive and Gram negative bacteria. The comparison of antibacterial and antimycobacterial results indicated that different structural requirements are necessary for a compound to be effective against bacterial and mycobacterial targets.     

对甲苯磺酸索拉非尼的合成

4-氯-3-三氟甲基苯胺(5)和氯甲酸苯酯反应得到[4-氯-3-(三氟甲基)苯基]氨基甲酸苯酯(6),再和对氨基苯酚缩合得到N-[4-氯-3-(三氟甲基)苯基]-N-(4-羟基苯基)脲(7)。另用2-吡啶甲酸(2)经氯化、酰胺化得中间体N-甲基-(4-氯-2-吡啶基)甲酰胺(4)。4和7经亲核取代及成盐反应制得对甲苯磺酸索拉非尼,总收率约62%(以5计)。     

N-取代苯基-5-取代苯基-3H-1,2,4-三唑-3-硫酮衍生物的合成及抗菌活性研究

目的 以苯甲酸为原料,经4步反应合成一系列N-取代苯基-5-取代苯基-3H-1,2,4-三氮唑-3-硫酮化合物并研究其抗菌活性。方法 基于课题组前期对新型潜在三唑类抗菌化合物6h的作用机制研究,筛选多个侧链基团,使用乙醇和碳酸钠作溶剂改善最后一步反应条件,通过硅胶柱色谱分离纯化目标化合物,合成一系列1,2,4-三唑类化合物并采用质谱(MS)和1H NMR、13C NMR进行结构表征。通过琼脂扩散法初步筛选所有化合物对肺炎克雷伯菌、金黄色葡萄球菌和铜绿假单胞菌3种常见菌株的抗菌活性,并通过微量稀释法进一步测定它们的最小抑菌浓度(MIC值)。结果 合成17个含有卤代苯基和其他侧链基团的目标化合物,其MS以及核磁共振谱图数据表明所有化合物结构正确。抗菌活性初步筛选可知化合物6a、6b、6d、6f、6g、6h、6k、6m和6p等9个化合物具有不错的抑菌能力,其MIC测试结果表明,大部分化合物对所测菌株的MIC值在25~100μg/mL范围内。尤其是化合物6h和6k对肺炎克雷伯菌的MIC值达到25μg/mL,抑菌活性与对照药物氨苄西林相当。结论 在前期作用机制研究基础上,通过对构效关系的阐述,发现一些侧链片段如间位卤代苯基或对位卤代苯基、三氟甲基苯基等具有吸电子基团的苯基、吡啶基等对1,2,4-三唑类衍生物的抗菌活性有明显增强作用,证实侧链基团与受体蛋白形成特异性协调作用和氢键作用从而发挥衍生物的抗菌活性。     

Synthesis, biological activity, and SAR of antimycobacterial 9-aryl-, 9-arylsulfonyl-, and 9-benzyl-6-(2-furyl)purines

9-Aryl-, 9-arylsulfonyl- and 9-benzyl-6-(2-furyl)purines were synthesized by N-alkylation or N-arylation of the purine followed by Stille coupling to introduce the furyl substituent in the 6-position and the compounds screened for activity against Mycobacterium tuberculosis. The 9-aryl- and 9-sulfonylarylpurines exhibited weak activity toward the bacteria, but 9-benzylpurines were good inhibitors especially those carrying electron-donating substituents on the phenyl ring. A chlorine atom in the purine 2-position further enhanced activity. The high antimycobacterial activity (MIC 0.39 microg/mL against M. tuberculosis), low toxicity against mammalian cells and activity inside macrophages found for 2-chloro-6-(2-furyl)-9-(4-methoxyphenylmethyl)-9H-purine makes this compound a highly interesting potential antituberculosis drug.     

Synthesis and anticonvulsant activity of new <Emphasis Type="Italic">N</Emphasis>-phenyl-2-(4-phenylpiperazin-1-yl)acetamide derivatives

Twenty-two new N-phenyl-2-(4-phenylpiperazin-1-yl)acetamide derivatives have been synthesized and evaluated for their anticonvulsant activity in animal models of epilepsy. These molecules have been designed as analogs of previously obtained anticonvulsant active pyrrolidine-2,5-diones in which heterocyclic imide ring has been changed into chain amide bound. The final compounds were synthesized in the alkylation reaction of the corresponding amines with the previously obtained alkylating reagents 2-chloro-1-(3-chlorophenyl)ethanone (1) or 2-chloro-1-[3-(trifluoromethyl)phenyl]ethanone (2). Initial anticonvulsant screening was performed using standard maximal electroshock (MES) and subcutaneous pentylenetetrazole screens in mice and/or rats. Several compounds were tested additionally in the psychomotor seizures (6-Hz model). The acute neurological toxicity was determined applying the rotarod test. The results of pharmacological studies showed activity exclusively in the MES seizures especially for 3-(trifluoromethyl)anilide derivatives, whereas majority of 3-chloroanilide analogs were inactive. It should be emphasize that several molecules showed also activity in the 6-Hz screen which is an animal model of human partial and therapy-resistant epilepsy. In the in vitro studies, the most potent derivative 20 was observed as moderate binder to the neuronal voltage-sensitive sodium channels (site 2). The SAR studies for anticonvulsant activity confirmed the crucial role of pyrrolidine-2,5-dione core fragment for anticonvulsant activity.     

新糖脂类化合物抗革兰阳性球菌作用机制研究

目的研究新糖脂化合物二鼠李糖脂衍生化合物7(DDC7)和鼠李糖脂(C5)抗革兰阳性球菌的作用机制。方法分离纯化金黄色葡萄球菌(ATCC29213)的细胞壁肽聚糖。依据已知新化合物对ATCC29213的MIC结果,用肉汤二倍稀释法,观察新化合物DDC7、C5分别加入不同浓度肽聚糖后,对ATCC29213生长的影响。结果新化合物DDC7、C5对ATCC29213的MIC均为16μg·mL-1。当加入肽聚糖浓度≥32μg·mL-1时,可以阻断新化合物DDC7、C5对ATCC29213的抑菌作用。结论新糖脂类化合物抗菌作用部位在革兰阳性球菌细胞壁肽聚糖上。     

Synthesis and antimicrobial activity of some novel 2,5- and/or 6-substituted benzoxazole and benzimidazole derivatives

A new series of 2,5- and/or 6-substituted benzoxazoles (7a–f), benzimidazoles (8a–g) holding cyclohexyl or cyclopentyl moieties at position 2 and 5- or 6-substituted-2-cyclohexylaminomethylbenzoxazoles (9a, b) was synthesized in order to determine their antimicrobial activities and feasible structure–activity relationships. The synthesized compounds were tested in vitro against three Gram-positive, two Gram-negative bacteria and the yeast Candida albicans in comparison with several control drugs. Microbiological results showed that the synthesized compounds were possessing a broad spectrum of antibacterial activity against the tested microorganisms. 5-Chloro-2-(2-cyclohexylethyl)benzimidazole (8g) was found as the most active compound against the screened Gram-positive bacteria strains at a minimum inhibitory concentration (MIC) value of 12.5 μg/ml. However, it exhibited lower antibacterial potency than the compared control drugs. On the other side, compounds 7–9 indicated significant antibacterial activity against the Gram-negative enterobacter Pseudomonas aeruginosa having MIC values of 50 μg/ml, providing either the same effect as tetracycline or higher activity than streptomycin, but showing less potency than the compared control drug gentamycin. Moreover, the synthesized compounds also possessed antimycotic activity against the yeast C. albicans showing MIC values between 25–50 μg/ml.     

Patent Evaluation: Antibacterial Condensed Carbapenems

Summary

Novelty: Novel condensed carbapenems are described. These compounds, containing an amidine group, are claimed to have antibacterial activity and are potentially useful in the treatment or prophylaxis of systemic or topical infections. A process for the synthesis of these tricyclic carbapenems is also claimed.

Biology: The specific compound is shown to have antibacterial activity against Gram-positive bacteria (MIC 0.1-1 μg/ml), Gram-negative bacteria (E. coli 1852E 0.5 μg/ml, Ps. aeruginosa 1911E 8 μg/ml) and also anaerobes (B. fragilis 2017E 0.2 μg/ml). No adverse effects were observed in toxicological studies in mouse and rat at 500 mg/kg iv.

Chemistry: The syntheses of seven intermediates and two examples by modification of known methods are fully detailed. Only one compound is specifically claimed, (4S,8S,9R,10S,12R)-4-(N-methylformamidino)-10-(1-hydroxyethyl)-11-oxo-1-azatricyclo[7.2.0.0³⁸]undec-2-ene-2-carboxylic acid.     

Discovery of 4-Pyridone derivatives as specific inhibitors of enoyl-acyl carrier protein reductase (FabI) with antibacterial activity against Staphylococcus aureus

4-Pyridone derivatives were identified as potent inhibitors of FabI, the enoyl-acyl carrier protein reductase in Escherichia coli and Staphylococcus aureus. 1-Substituted derivatives of a hit compound exhibited potent antibacterial activities against S. aureus. Target specificity of 4-pyridone derivatives was confirmed by the strong inhibition of lipid synthesis in macromolecular biosynthesis assay and also by the reduced antimicrobial activity against triclosan-resistant S. aureus isolates possessing a point mutation (Ala95Val) in FabI. Two 4-pyridone compounds exhibited strong antibacterial activities against 30 clinical isolates of methicillin-resistant S. aureus (MRSA) with MIC(90) of 0.5 and 2 mug/ml, respectively. Moreover, they retained activity against S. aureus with a mutation affecting FabI residue 204, which was recently found to be associated with triclosan resistance in clinical isolates of S. aureus. In conclusion, we have identified a novel chemical series, 4-pyridone derivatives, as specific inhibitors of FabI with potent antibacterial activity against S. aureus.     

Alkenylidene bisphenols, a new class of bisphenol bactericide.

Alkenylidene bisphenols are prepared by condensation of an appropriate phenol with a haloacetaldehyde, followed by base-induced elimination, or by condensation of the corresponding aryl methyl ether, elimination, and deprotection of the phenol with boron tribromide. The resulting compounds may be further elaborated by reactions on the aromatic nucleus. A series of 13 such compounds showed activity against Staphylococcus aureus; the most active was 1,1-dichloro-2-(3-allyl-5-chloro-2-hydroxphenyl)-2-(5-chloro-2-hydroxyphenyl)ethylene (16), MIC 0.16 microgram/mL. 1,1-Dichloro-2,2-bis(5-chloro-2-hydroxyphenyl)ethylene (6) was similar in its activity and spectrum to hexachlorophene.     

3-取代苯基苯并吡喃酮类化合物 的设计合成及抗肿瘤活性

目的 在7-甲氧基或7-羟基苯并吡喃酮的3位引入各种取代苯基,以发现抗肿瘤活性更强的异黄酮类化合物。方法 以丹皮酚和甲酸乙酯为原料,经多步反应制得关键中间体3-碘-7-甲氧基苯并吡喃酮(5),再经Suzuki coupling反应制得目标化合物,通过1H-NMR、MS和IR方法确定目标化合物的结构,部分化合物还进行了13C-NMR测定。选择人结肠癌细胞株HCT116和人肝癌细胞株7721为试验瘤株,以姜黄素和大豆异黄酮为阳性对照测定体外抗肿瘤活性。结果 设计合成的20个新目标化合物均有一定的体外抗肿瘤活性,其中化合物6, 9, 16和19的活性较好,与对照品姜黄素的IC50值相当, 明显优于对照品大豆异黄酮的IC50值。结论 可以通过引入不同的3-取代苯基改变异黄酮类化合物的抗肿瘤活性;在这类化合物的3位苯基上引入甲基、甲氧基或三氟甲基体积较小的基团似乎有利于其抗肿瘤活性。 关键词：化学合成; 苯并吡喃酮; Suzuki coupling偶联反应; 抗肿瘤活性     

Synthesis and antimicrobial activity of some novel 2-(p-substituted-phenyl)-5-substituted-carbonylaminobenzoxazoles

A series of 2-(p-substituted-phenyl)-5-substituted-carbonylamino benzoxazole derivatives (5-22) was synthesized and their antimicrobial activities determined in comparison to several control drugs. The synthesized compounds were tested in vitro against Staphylococcus aureus, Streptococcus faecalis and Bacillus subtilis as Gram-positive, Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and the yeast Candida albicans. Microbiological results showed that the compounds possessed a diffuse spectrum of antibacterial activity against these microorganisms. Compound 9 which bears a phenylacetamido moiety at position 5 and a 4-fluorophenyl group at the 2-position of benzoxazole ring was the most active derivative against S. aureus, S. faecalis and P. aeruginosa with a MIC value of 12.5 microg/ml. Compound 11 provided higher potency than the other tested compounds against B. subtilis at a MIC value of 12.5 microg/ml. Compounds 5-22 showed antifungal activity against C. albicans with MIC values between 50 and 12.5 microg/ml.     

Antibacterial compounds from Zanthoxylum rhetsa

A new amide, zanthorhetsamide (1), along with nine known compounds (2-10) was isolated from the roots and stem barks of Zanthoxylum rhetsa. The structure was characterized by spectroscopic methods. In addition, the antibacterial activity of the isolates was evaluated. Dihydrochelerythrine (4) exhibited strong activity against methicillin-resistant Staphylococcus aureus SK1 and moderate activity against Escherichia coli TISTR 780 with MIC values of 8 and 16 μg/mL, respectively.