Synthesis and Evaluation of Imidazole Derivatives Bearing Imidazo[2,1-b] [1,3,4]thiadiazole Moiety as Antibacterial Agents.

Background: Drug-resistant infections kill hundreds of thousands of people globally every year. In previous work, we found that tri-methoxy- and pyridine-substituted imidazoles show strong antibacterial activities.

Objective: The aim of this work was to investigate the antibacterial activities and bacterial resistances of imidazoles bearing an aromatic heterocyclic, alkoxy, or polycyclic moiety on the central ring.

Synthesis and Evaluation of Chiral Rhodanine Derivatives Bearing Quinoxalinyl Imidazole Moiety as ALK5 Inhibitors.

Background: TGF-β signaling pathway inhibition is considered an effective way to prevent the development of several diseases. In the design and synthesis of TGF-β inhibitors, a rhodanine compound containing a quinoxalinyl imidazole moiety was found to have strong antimicrobial activity.

Objective: The purpose of this work was to investigate the antimicrobial activity of other chiral rhodanine TGF-β inhibitors synthesized.

Synthesis and Antimicrobial Activity Evaluation of Imidazole-Fused Imidazo[2,1-b][1,3,4]thiadiazole Analogues.

Three series of new imidazole-fused imidazo[2,1-b][1,3,4]thiadiazole analogues (compounds 20 a-g, 21 a-g, and 22 a-g) have been synthesized, and their antibacterial and antifungal activities have been evaluated. All the target compounds showed strong antifungal activity and high selectivity for the test fungus Candida albicans over Gram-positive and -negative bacteria. N-((4-(2-Cyclopropyl-6-(4-fluorophenyl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-5-(6-methyl-pyridin-2-yl)-1H-imidazol-2-yl)methyl)aniline (21 a) showed the highest activity against C.

Design, synthesis and evaluation of carbazole derivatives as potential antimicrobial agents.

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml.

Synthesis of novel dihydrotriazine derivatives bearing 1,3-diaryl pyrazole moieties as potential antibacterial agents.

Three novel series of dihydrotriazine derivatives bearing 1,3-diaryl pyrazole moieties were designed, synthesized and evaluated in terms of their antibacterial and antifungal activities. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains (including multidrug-resistant clinical isolates) and Gram-negative bacterial strains with minimum inhibitory concentration values in the range of 1-64 µg/mL. Compounds 4b and 4c presented the most potent inhibitory activity against Gram-positive bacteria (S.

Synthesis and evaluation of the antibacterial activities of aryl substituted dihydrotriazine derivatives.

Five series of dihydrotriazine derivatives containing chalcone (13a-i), phenoxy acetophenone (14a-b), benzyl benzene (15a-c), naphthoxyl acetophenone (16a-b) and benzyl naphthalene (17a-h) moieties were designed and synthesized. The antibacterial and antifungal activities of these compounds were evaluated against several strains of Gram-positive and Gram-negative bacteria, as well as a single fungus. Compound 17h was found to be the most potent of all of the compounds tested, with an MIC value of 0.

Madurahydroxylactone, an Inhibitor of FtsZ from sp. AN100570.

FtsZ, a bacterial cell-division protein, is an attractive antibacterial target. In the screening for an inhibitor of FtsZ, madurahydroxylactone () and its related derivatives 2-5 were isolated from sp. AN100570.

Synthesis and biological evaluation of chalcone derivatives containing aminoguanidine or acylhydrazone moieties.

Three novel series of chalcone derivatives containing an aminoguanidine or acylhydrazone moiety were designed, synthesized and evaluated in terms of their antibacterial, antifungal and anti-inflammatory activities. Most of the synthesized compounds showed potent inhibitory activity towards various bacteria and one fungus with minimum inhibitory concentrations (MICs) ranging from 1 to 8μg/mL. Compared with our previously reported chalcone derivatives (MICs >64μg/mL), these compounds exhibited improved antibacterial activities (MICs=2μg/mL) against Gram-negative bacterial strains (Escherichia coli 1924 and 1356).

Synthesis and Antimicrobial Evaluation of (Z)-5-((3-phenyl-1H-pyrazol-4- yl)methylene)-2-thioxothiazolidin-4-one Derivatives.

Background: An alarming increment in pathogenic resistance to existing anti-microbial agents is a serious problem and the treatment of these bacterial infections is becoming increasingly challenging. Therefore, there is an urgent need to develop novel antimicrobial agents.

Objective: As a part of our ongoing studies toward the development of novel antibacterial agents, the synthesis and antibacterial activity of a series of (Z)-5-((3-phenyl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one derivatives will be discussed in this study.

Synthesis and biological evaluation of 1,3-diaryl pyrazole derivatives as potential antibacterial and anti-inflammatory agents.

Three series of 1,3-diaryl pyrazole derivatives bearing aminoguanidine or furan-2-carbohydrazide moieties have been synthesized, characterized and evaluated for antibacterial and anti-inflammatory activities. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains (including multidrug-resistant clinical isolates) and Gram-negative bacterial strains with minimum inhibitory concentration values in the range of 1-64 μg/mL. Compounds 6g, 6l and 7l presented the most potent inhibitory activity against Gram-positive bacteria (e.

Synthesis and antimicrobial evaluation of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety.

Three series of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety (5a-k, 6a-i, and 7a-i) have been synthesized, characterized and evaluated for their antibacterial activity. Some of these displayed potent antibacterial activity against several Gram-positive and Gram-negative bacterial strains (including multidrug-resistant clinical isolates) with minimum inhibitory concentration (MIC) values in the range of 4-64 μg/mL and minimum bactericidal concentration (MBC) values in the range of 8-256 μg/mL. Compared with previously reported rhodanine derivatives, these compounds exhibited a broad spectrum of antibacterial activity by means of introducing 4-amino-5-aryl-1,2,4-triazole-3-thione moiety.

Synthesis and Antibacterial Evaluation of (S,Z)-4-methyl-2-(4-oxo-5-((5-substituted phenylfuran-2-yl) methylene)-2-thioxothiazolidin-3-yl)Pentanoic Acids.

The microbial resistance has become a global hazard with the irrational use of antibiotics. Infection of drug-resistant bacteria seriously threatens human health. Currently, there is an urgent need for the development of novel antimicrobial agents with new mechanisms and lower levels of toxicity.

Synthesis and evaluation of the antimicrobial activities of 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)-2-thioxothiazolidin-4-one derivatives.

Two novel series of 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)-2-thioxothiazolidin-4-one derivatives were designed and synthesized, and their anti-bacterial activities evaluated. These compounds showed broad-spectrum inhibitory activities against both Gram-positive and Gram-negative bacteria with minimum inhibitory concentration (MIC) values in the range of 1-64 μg/mL. The activity of compound 6c was the more potent with MIC values of 1 μg/mL against the MRSA (3167 and 3506) strains than those of gatifloxacin, oxacillin, and norfloxacin.

Meleagrin, a new FabI inhibitor from Penicillium chryosogenum with at least one additional mode of action.

Bacterial enoyl-acyl carrier protein reductase (FabI) is a promising novel antibacterial target. We isolated a new class of FabI inhibitor from Penicillium chrysogenum, which produces various antibiotics, the mechanisms of some of them are unknown. The isolated FabI inhibitor was determined to be meleagrin by mass spectroscopy and nuclear magnetic resonance spectral analyses, and its more active and inactive derivatives were chemically prepared.

Synthesis and biological evaluation of (E)-1-(substituted)-3-phenylprop-2-en-1-ones bearing rhodanines as potent anti-microbial agents.

Herein, we report the design, syntheses and in vitro anti-microbial activity of two series of rhodanines with chalcone moiety. Anti-microbial tests showed that some of the synthesized compounds exhibited good inhibition (MIC = 1-8 µg/mL) against multi-drug-resistant Gram-positive organisms, including methicillin resistant and quinolone-resistant Staphylococcus aureus, in which the compound 4g was found to be the most potent with minimum inhibitory concentration (MIC) value of 1 µg/mL against two methicillin-resistant S. aureus.

Novel arylhydrazone derivatives bearing a rhodanine moiety: synthesis and evaluation of their antibacterial activities.

A series of arylhydrazone derivatives bearing a rhodanine moiety have been synthesized, characterized, and evaluated as antibacterial agents. Some of these compounds showed potent antibacterial activities against several different strains of Gram-positive bacteria, including multidrug-resistant clinical isolates. Of the compounds tested, IIk and IIIk were identified as the most effective, with minimum inhibitory concentration values of 2-4 μg/mL against multidrug-resistant Gram-positive organisms, including methicillin-resistant and quinolone-resistant Staphylococcus aureus.

Synthesis and biological evaluation of rhodanine derivatives bearing a quinoline moiety as potent antimicrobial agents.

Three series of rhodanine derivatives bearing a quinoline moiety (6a-h, 7a-g, and 8a-e) have been synthesized, characterized, and evaluated as antibacterial agents. The majority of these compounds showed potent antibacterial activities against several different strains of Gram-positive bacteria, including multidrug-resistant clinical isolates. Of the compounds tested, 6g and 8c were identified as the most effective with minimum inhibitory concentration (MIC) values of 1 μg/mL against multidrug-resistant Gram-positive organisms, including methicillin-resistant and quinolone-resistant Staphylococcus aureus (MRSA and QRSA, respectively).

Synthesis and antibacterial evaluation of rhodanine-based 5-aryloxy pyrazoles against selected methicillin resistant and quinolone-resistant Staphylococcus aureus (MRSA and QRSA).

With an intention to synergize the anti-bacterial activity of 5-aryloxy pyrazole and rhodanine derivatives, eight series of hybrid compounds have been synthesized and evaluated for their antibacterial activity. The majority of the synthesized compounds showed good inhibitory activity against selected methicillin resistant and quinolone-resistant Staphylococcus aureus (MRSA, QRSA) with minimum inhibitory concentration (MIC) values in the range of 1-32 μg/mL. The cytotoxicity test suggests that these compounds exhibited in vitro antibacterial activity at non-cytotoxic concentrations.

Synthesis and antibacterial activity of novel 1,3-diphenyl-1H-pyrazoles functionalized with phenylalanine-derived rhodanines.

In the present study, a series of novel 1,3-diphenyl-1H-pyrazoles functionalized with phenylalanine-derived rhodanine derivatives were synthesized and evaluated for their antibacterial activity. Compounds 4, 6, 9, 10, 12 and 15 exhibited stronger activity than the standard drugs, norfloxacin and oxacillin, with MIC values of 1 μg/mL against methicillin-resistant Staphylococcus aureus and quinolone-resistant S. aureus.

Synthesis and biological evaluation of 5-aryloxypyrazole derivatives bearing a rhodanine-3-aromatic acid as potential antimicrobial agents.

Three novel series of 5-aryloxypyrazole derivatives have been synthesized and tested for their antibacterial activity. The majority of the synthesized compounds showed potent inhibitory activity against Gram-positive bacteria Staphylococcus aureus 4220, especially against the strains of multidrug-resistant clinical isolates (MRSA3167/3506 and QRSA3505/3519). Among which compounds IIIb, IIIg and IIIm showed the most potent levels of activity (MIC=1 μg/mL) against the multidrug-resistant strains.

Synthesis and antimicrobial evaluation of L-phenylalanine-derived C5-substituted rhodanine and chalcone derivatives containing thiobarbituric acid or 2-thioxo-4-thiazolidinone.

Four novel series of compounds, including the l-phenylalanine-derived C5-substituted rhodanine (6a-q, 7a-j) and chalcone derivatives containing thiobarbituric acid or 2-thioxo-4-thiazolidinone (9a-e, 11a-e) have been designed, synthesized, characterized, and evaluated for their antibacterial activity. Some of these compounds showed significant antibacterial activity against Gram-positive bacterias, especially against the strains of multidrug-resistant clinical isolates, among which compounds 6c-e, 6g, 6i, 6j and 6q exhibiting high levels of antimicrobial activity against Staphylococcus aureus RN4220 with minimum inhibitory concentration (MIC) values of 2 μg/mL. Compound 6q showed the most potent activity of all of the compounds against all of the test multidrug-resistant clinical isolates tested.

Synthesis and bioactivity evaluation of rhodanine derivatives as potential anti-bacterial agents.

Five series of (Z)-5-(4-(2-oxo-2-phenylethoxy)benzylidene)-2-thioxothiazolidin-4-one derivatives (I-V) were synthesized, characterized, and evaluated for their anti-bacterial activity. Most of the synthesized compounds showed potent inhibition against several Gram-positive bacteria (including multidrug-resistant clinical isolates) with MIC values in the range of 1-32 μg/mL. Compounds IIIi, Vb and Vc presented the most potent activity, showing four-fold more potency than norfloxacin (MIC = 8 μg/mL and 4 μg/mL) and 64-fold more activity than oxacillin (MIC > 64 μg/mL) against MRSA CCARM 3167 and 3506 strains with MIC values of 1 μg/mL, and 64-fold more potency than norfloxacin (MIC > 64 μg/mL) and comparable activity to oxacillin (MIC = 1 μg/mL) against the QRSA CCARM 3505 and 3519 strains.

Synthesis of novel 1,3-diaryl pyrazole derivatives bearing rhodanine-3-fatty acid moieties as potential antibacterial agents.

In the present study, a series of 1,3-diaryl pyrazole derivatives bearing rhodanine-3-fatty acid moieties were synthesized and their antimicrobial activities were tested against various Gram-positive and Gram-negative bacteria. 1,3-diaryl-4-formylpyrazoles were synthesized as key intermediates following a Vilsmeier-Haack strategy. Several compounds with an MIC of 2 μg/mL, exhibited stronger antibacterial activity against the methicillin-resistant Staphylococcus aureus (MRSA) than the controls.

Synthesis and anti-bacterial activity of some heterocyclic chalcone derivatives bearing thiofuran, furan, and quinoline moieties.

36 Novel heterocyclic chalcone derivatives were synthesized and tested for their anti-bacterial activity. Some compounds presented good anti-microbial activities against Gram-positive bacteria (including the multidrug-resistant clinical isolates). This class of compounds presented high potency against Streptococcus mutans, among which the derivatives F2 with an MIC of 2 µg/mL was as active as the standard drug (norfloxacin) and less active than oxacillin.

Synthesis of new chalcone derivatives bearing 2,4-thiazolidinedione and benzoic acid moieties as potential anti-bacterial agents.

A series of chalcone derivatives bearing the 2,4-thiazolidinedione and benzoic acid moieties (8a-s) were synthesized, characterized, and evaluated for their anti-bacterial activity. Among the tested compounds, the most effective were 8a, 8h, 8k, 8n and 8q with MIC value in the range of 0.5-4 μg/mL against six Gram-positive bacteria (including multidrug-resistant clinical isolates).