Synthesis and in vitro antimicrobial evaluation of 5-(1-methyl-5-nitro-2-imidazolyl)-4H-1,2,4-triazoles

The increasing clinical importance of drug-resistant pathogens has lent additional urgency to antimicrobial research. Various 5-(1-methyl-5-nitro-2-imidazolyl)-4H-1,2,4-triazoles (4a-6f) were synthesized and tested in vitro for their antibacterial and antifungal activities. Compounds 4a and 4b exhibited significant effects against Bacillus subtilis at MIC ranges of 0.5-1 microg/mL and moderate effects against Staphylococcus aureus.     

5-Nitroimidazole-based 1,3,4-thiadiazoles: heterocyclic analogs of metronidazole as anti-Helicobacter pylori agents

A series of 5‐nitroimidazole‐based 1,3,4‐thiadiazoles were prepared and tested for antibacterial activity against Helicobacter pylori. The anti‐H. pylori activity of target compounds along with the commercially available antimicrobial metronidazole was evaluated by comparing the inhibition‐zone diameters determined by the paper disc diffusion bioassay. From our bioassay results against 20 clinical isolates it is evident that piperazinyl, 4‐methylpiperazinyl, 3‐methylpiperazinyl, and 3,5‐dimethylpiperazinyl analogs ( 6a , 6b , 6e , and 6f , respectively) and pyrrolidine derivative 7 had strong activity at 0.5 µg/disc (average of inhibition zone >20 mm) while metronidazole had no activity at this dose. Compound 6f containing the 3,5‐dimethylpiperazinyl moiety at the 2‐position of the 5‐(1‐methyl‐5‐nitro‐1H‐imidazol‐2‐yl)‐1,3,4‐thiadiazole skeleton was the most potent compound tested at low concentrations.     

Substituted quinazolines,part 2. Synthesis and in-vitro anticancer evaluation of new 2-substituted mercapto-3H-quinazoline analogs

A new series of 2-substituted mercapto-3H-quinozolines bearing 6-iodo and 2-heteroarylthio functions was synthesized and screened for their in vitro antitumor activity. Eighteen compounds were identified as active anticancer agents. N'-[(3-Benzyl-4-oxo-6-iodo-3H-quinazoline-2-yl)thioacetyl]-N(3)-ethylthiosemicarbazide (10), N-benzoyl-N'-[2-(3-benzyl-4-oxo-6-iodo-3H-quinozolin-2-yl)thioacetyl]hydrazine (12), and 2-[(3, 6-dioxo-pyridazin-4-yl)thio]-3-benzyl-4-oxo-6-iodo-3H-quinazoline (20) proved to be the most active members in this study. They showed MG-MID, GI(50) values of 12.8, 11.3, and 13.8 microM, respectively. The detailed synthesis and biological screening data are reported.     

Synthesis and antibacterial activity of 4-benzoyl-1-methyl-5-phenyl-1H-pyrazole-3-carboxylic acid and derivatives

Some new 1H-pyrazole-3-carboxylic acid and pyridazinone derivatives were synthesized and evaluated for their antibacterial activities against Bacillus cereus ATCC 7064, Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 4230 and Pseudomonas putida using tube dilution method. The minimal inhibitory concentrations (MICs) experiments revealed that all chemical compounds showed inhibitor effects on the growth of the test microorganisms. Moreover, the results of this research showed that the compound named as 5c was the best compound in the series, exhibiting antibacterial activity against both Gram-positive and Gram-negative bacteria.     

New amides of 5-acylamino-3-methyl-4-isothiazolecarboxylic acid and their immunotropic activity

Several new amides 4 of 5-substituted 3-methyl-4-isothiazolecarboxylic acid were obtained. These compounds have acetylamino or benzoylamino groups in position 5 of the isothiazole ring. In position 4, the carboxylic group was transformed in the amides using amino-acid esters. Activities of the obtained derivatives were checked in the humoral immune response and delayed type hypersensitivity reaction to sheep red blood cells (SRBCs) in vivo.     

Synthesis, antimicrobial evaluation, and docking studies of novel 4-substituted quinazoline derivatives as DNA-gyrase inhibitors

Quinazoline derivatives are reported to have anti‐inflammatory, analgesic, antibacterial, and anticancer activities. The incorporation of “OCH₂CONH₂” (oxymethylcarbamide) at 4^th position of the quinazoline ring was found to influence the biological activities of the molecules. With this rationale, some new oxadiazolyl methyloxy quinazolines, pyrazolyl acetoxy methyl quinazolines, triazolylmethyloxy quinazolines were synthesized from anthranilic acid through quinazolyl oxyacetylhydrazide intermediates. All the compounds were characterized by IR, ¹H‐NMR, EI‐MS, and C, H, N analyses and evaluated for their antimicrobial activity. Docking studies on the DNA‐gyrase enzyme (1KZN) show their role in the antimicrobial activity of the molecules and explain the higher potency of compounds 6a , 6b , 8a , 8b based on ReRanking scores and binding poses of the molecules.     

Synthesis and antibacterial activity of some imidazole-5-(4H)one derivatives

In the present study, several substituted oxazolones were synthesized by condensation of benzoylglycine with different aldehydes. From such oxazolones, substituted imidazolones were synthesized by condensation with ethylenediamine, urea and 4-N,N-dimethylaminoaniline. All these synthesized compounds produced significant antibacterial activities. Furthermore, compounds containing -CH(2)CH(2)NH(2), -CONH(2) and -C(6)H(4)-N(CH(3))(2) groups as substitutents on the imidazolones were found to be potent antibacterial agents. Thus, among the twelve compounds, 1-(2-aminoethyl)-2-phen yl-4-(4-(dimethylamino)benzylidene)imidazole-5-(4H)one (4d), 1-carboxamido-2-phenyl-4-(4-(dimethylamino)benzylidene)imidazole-5-(4H)one (4e) and 1-(4-(N,N-dimethylamino)phenyl)-2-phenyl-4-(4-(dimethylamino)benzylidene)imidazole-5-(4H)one (4f) were found to have a significant higher antibacterial activity than the other substituted imidazolones. Compound 4e was the most active one in this series.     

Synthesis and calcium channel antagonist activities of 3-nitrooxyalkyl, 5-alkyl 1,4-dihydro-2,6-dimethyl-4-(1-methyl-5-nitro-2-imidazolyl)-3, 5-pyridinedicarboxylates

A group of racemic 3-[(2-nitrooxyethyl), (3-nitrooxypropyl), (4-nitrooxybutyl) or (1,3-dinitrooxy-2-propyl)], 5-methyl (ethyl or propyl) 1,4-dihydro-2,6-dimethyl-4-(1-methyl-5-nitro-2-imidazolyl)-3,5-pyridinedicarboxylates (18-29) were synthesized using modified Hantzsch reaction that involved the condensation of 2-nitrooxyethyl (8), 3-nitrooxypropyl (9), 4-nitrooxybutyl (10) or 1,3-dinitrooxy-2-propyl (13) acetoacetate with methyl (14), ethyl (15) or isopropyl (16) 3-aminocrotonate and 1-methyl-5-nitroimidazole-2-carboxaldehyde (17). In vitro calcium channel antagonist activities were determined using a guinea pig ileum longitudinal smooth muscle assay. Compounds 18-29 exhibited superior, or equipotent, calcium antagonist activity (IC50= 10(11) - 10(-13) M range) relative to the reference drug nifedipine (IC50 = 1.07 +/- 0.12 x 10(-11) M), which could serve as potential probes to investigate the in vivo release of nitric oxide which induces vascular muscle relaxation.     

Synthesis and evaluation of anticonvulsant and antimicrobial activities of 3-hydroxy-6-methyl-2-substituted 4h-pyran-4-one derivatives

In this study, thirteen 3-hydroxy-6-methyl-2-substituted 4H-pyran-4-one derivatives were synthesized for the evaluation of their potential anticonvulsant activity. Mannich bases were prepared by the reaction of substituted piperazine derivatives with allomaltol and formaline. The structures of the synthesized compounds were confirmed by IR, (1)H-NMR and elemental analysis. Their anticonvulsant activities were determined in vivo by maximal electroshock (MES), sub-cutaneous Metrazol (scMet), and rotorod toxicity tests for neurological deficits. The antimicrobial activities of the synthesized compounds were investigated in vitro against some bacteria and fungi using the microdilution broth method. Ac-cording to the activity studies, 3-hydroxy-6-methyl-2-[4-(2-trifluoromethyl-phenyl)-piperazin-1-ylmethyl]-4H-pyran-4-one (3i) was the compound determined to be most active in the scMet test for all doses at four hours and for the 300 mg/kg dose at half an hour. 2-[4-(4-Chloro-phenyl)-piperazin-1-ylmethyl]-3-hydroxy-6-methyl-4H-pyran-4-one (3f) was found to be protective against MES whereas 2-chlorophenyl derivative (3e) was not. Looking at the antifungal activity results, compounds 3b, 3h, and 3i were determined to have activity against all fungi.     

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.     

Synthesis and antibacterial activity of 1beta-methyl-2-(5-substituted oxadiazolo pyrrolidin-3-yl-thio)carbapenem derivatives

Synthesis of a new series of 1beta-methylcarbapenems with a substituted oxadiazolopyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of the substituent on the oxadiazole ring investigated. In particular, compounds 13a and 13c with ester and carbamoyl substituted oxadiazole moieties showed the most potent antibacterial activity.     

Synthesis and antibacterial activity and antifungal activity of 2-R-4-R′-quinolines

2-R-4-R′-quinolines, where R is a thienyl-2,2,2′-bithienyl-5-yl, or 1,1′-biphenyl-4-yl group and R′ is an azidocarbonyl- or carboethoxyamino group, were found to have antimicrobial activity against the diphtheria bacillus and Staphylococcus P-209. Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 43, No. 1, pp. 12–13, January, 2009.     

Synthesis and antibacterial activity of 1 beta-methyl-2-(5-substituted imidazolino pyrrolidin-3-ylthio)carbapenem derivatives

The synthesis of a new series of 1 beta-methylcarbapenems containing a substituted imidazolino pyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of the substituent on the imidazoline ring was investigated. Compound 13 g which has a N-sulfonylmethyl substituted imidazoline moiety showed the most potent antibacterial activity.     

11个单环β-内酰胺类化合物的合成及其抗菌活性初探

根据单环β—内酰胺类化合物定量构效关系研究的结果提示，以N-苄基-3(S)-邻苯二甲酰亚胺基-4(S)-[4(S)-2，2-二甲基-1，3二氧环戊-4-基]-2-氧吖丁啶为原料，设计合成了11个新的单环β—内酰胺类化合物，其结构经MS、^1H—NMR或IR所确证，并测定了它们的体外抗菌活性，结果表明，它们均有抗菌作用，但抗菌活性低于对照品。     

7-(取代-5-氮杂螺[2,4]庚烷-5-基)喹诺酮类化合物的合成与抗菌作用

为寻找新的广谱、高效、低毒喹诺酮类抗菌药物,本文设计合成了9个7-(7-甲基氨甲基-5-氮杂螺2,4庚烷-5-基)-1-环丙基-6-氟-1,4-二氢-4-氧代-1,8-萘啶-3-羧酸及其类似物,其结构均经1H-NMR、MS所确证,并测定了它们的体外抗菌活性。结果表明,9个目标物均具有广谱活性,其中化合物23、26、27对10株革兰氏阳性菌的MIC值为0.01～0.12μg/ml,其活性远优于对照药加替沙星(MIC值为0.12～1μg/ml)和环丙沙星(MIC值为0.25～4μg/ml)。对10株革兰氏阴性菌的MIC值为0.01～2μg/ml,其活性基本与对照药相当或更优。     

Synthesis of 5-substituted 2-methylbenzimidazoles with anticancer activity

A series of compounds comprising the thiocarboximidopyrazolyl 5, the phenylpyrazolyl 6, the dimethylpyrazolyl 7, the nitrophenylpyrazolyl 8, the dimethyloxazolyl 9, the benzoxazepinyl 10, and pyrimidyl 11 a-c derivatives of 3-(2-methyl-1H-benzimidazol-5-ylazo)pentane-2, 4-dione was synthesized. Moreover, 5-amino-2-methylbenzimidazole (3) was reacted with phthalic anhydride or maleic anhydride in acetic acid or in toluene to produce 12-15. Treating 5, 6-diamino-2-methylbenzimidazole (16) with ethyl cyanoacetate or diethyl malonate or acetyl acetone leads to the formation of the benzodiazepine derivatives 17-20. The cytotoxic activity of the compounds 2, 7, 9, 10, and 11 was tested against 60 types of human cancer cell lines. Compounds 7 and 9 were found to be the most potent.     

含2-甲基-5-硝基咪唑的吡酮酸类衍生物的合成及其抗菌活性含2-甲基-5-硝基咪唑的吡酮酸类衍生物的合成及其抗菌活性

目的 研究含N-乙基-2-甲基-5-硝基咪唑的诺氟沙星、环丙沙星和依诺沙星衍生物的合成及其抗菌活性。方法 用含2-甲基-5-硝基咪唑的诺氟沙星、环丙沙星和依诺沙星等为原料,通过亲核取代、酯化合成目的物;测定目的物的抗菌活性。结果 设计、合成了9个新化合物(IIa～c,IIIa～f),其结构经MS,¹HNMR和元素分析确证。化合物IIa～c的体内抗菌活性较明显。结论 化合物IIa～c显示了一定的体内抗菌活性,值得进一步研究。     

Synthesis and antimicrobial activity of some new N-substituted quinoline derivatives of 1H-pyrazole

A new series of 32 derivatives of 4-pyrazolyl-N-(hetero)arylquinoline 5a-p and 6a-p were synthesized by a one-pot base-catalyzed cyclocondensation reaction of 1-phenyl-3-(hetero)aryl-pyrazole-4-carbaldehyde 1a-h, malononitrile 2, and 3-(hetero)aryl-5,5-disubstitutedcyclohex-2-enone 3a-b or 4a-b, respectively. All the synthesized compounds were characterized by elemental analysis, FT-IR, (1) H-NMR, and (13) C-NMR spectral data. All the synthesized compounds were screened, against six bacterial pathogens, namely Bacillus subtilis, Clostridium tetani, Streptococcus pneumoniae, Salmonella typhi, Vibrio cholerae, Escherichia coli, and antifungal activity, against two fungal pathogens Aspergillus fumigatus and Candida albicans, using broth microdilution MIC method. Some of the compounds were found to be more or equipotent against most of the employed strains than commercially available drugs as evident from the screening data.