Synthesis Of Antimicrobial Agents Research Articles

Benzosuberone as Precursor for Synthesis of Antimicrobial Agents: Synthesis, Antimicrobial Activity, and Molecular Docking

Based on the wide range of various biological activities of benzosuberone derivatives and the emergence of multidrug resistance (MDR) of the continued use of antibiotics among different breeds microorganisms, we synthesized herein a new series of benzosuberone derivatives via the reaction of 6-((5-methylfuran-2-yl)methylene)-6,7,8,9-tetrahydro-5H-benzo[7] annulen-5-one with nuecluophilic nitrogen compounds and hydrazonoyl halides. The structures of the new compounds were elucidated based on their IR, 1H-NMR and Mass spectra. Moreover, the potency of these compounds as antimicrobial agents has been evaluated. The results showed that some of the products have high activity exceed the used standard antibiotic. Additionally, the docking study was done to get the binding mode of the synthesized compounds with the binding site of the topoisomerase II enzyme. The results of molecular docking showed that the most active six derivatives are capable to fit in the binding pocket of topoisomerase II with binding energies ranging from –4.61 to –6.16 Kcal/mol.

Synthesis and evaluation of the antibacterial effect of titanium dioxide nanoparticles in comparison with ampicillin, colistin, and ertapenem on Staphylococcus aureus

Objectives: Today, the emergence of antibiotic-resistant strains and the acquisition of antibiotic resistance have caused many problems in the treatment of Staphylococcus aureus infection and is one of the most important health issues. At present, nanotechnology has a significant impact on the various fields including pharmacology, health, medicine, and food. This study aimed to synthesize the titanium dioxide nanoparticles (Tio2NPs) and its antibacterial effect on S. aureus compared with conventional antibiotics. Materials and Methods: In this study, Tio2NPs were tested on S. aureus compared with a number of antibiotics. First, Tio2NPs were synthesized. The shape and size of the particles as well as the synthesis quality were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering, zeta potential and X-ray diffraction, and Fourier-transform infrared spectroscopy. The antimicrobial effect of Tio2NPs on S. aureus strain (ATCC 12600) was then studied by disc diffusion method. Antibiotics of ampicillin, colistin, and ertapenem were used as control group. Results: Based on the results and given that the polydispersity index of the samples was below 0.5 (0.466), the other sample was estimated at 347.9 nm. The zeta potential of Tio2 sample was estimated at −9.48 indicating the stability of the nanoparticle and its suspension in a suitable amount per unit of time in the solution. The results of the AFM showed that the lower mean value obtained for the Tio2NPs was 0.5 nm, and the growth of the nanoparticles was noticeable in some regions and uniform and low in some others. The result of SEM showed that the size of the nanoparticle was 28.45–34.14 nm. The best inhibition zone diameter was obtained for ampicillin (30.66 mm), followed by ertapenem (15 mm) and Tio2(10 mm). Colistin without inhibition zone was identified as ineffective group. Conclusion: Due to the development of drug resistance to antibiotics, the production and synthesis of antimicrobial agents is one of the requirements of the current time. Due to the excellent synthesis of Tio2 and the presence of very fine nanoparticles, it can be used as a strong antimicrobial compound, especially on S. aureus infection.

Microwave-assisted synthesis of antimicrobial agents based on pyridazine moiety

An efficient and simple microwave assisted synthesis of sulfonamide derivatives incorporating the pyridazine moiety has been developed. These sulfonamides were used for the preparation of new heterocyclic compounds via reaction with different reagents using a microwave irradiation technique. The structures of the newly synthesized compounds were confirmed on the basis of FTIR, 1H and 13C-NMR, mass spectral techniques and elemental analyses. Some of the new synthesized compounds were assayed for their in vitro antibacterial activity against Gram-positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, Gram-negative bacteria, Escherichia coli and Klebsiella pneumonia and antifungal activity against Aspergillus fumigatus and Candida albicans. Most of the new compounds showed significant antibacterial and antifungal activity.

Genome Sequence of Pseudoalteromonas flavipulchra JG1, a Marine Antagonistic Bacterium with Abundant Antimicrobial Metabolites

The marine bacterium Pseudoalteromonas flavipulchra JG1 can synthesize various antibacterial metabolites, including protein and small molecules. The draft genome of JG1 is about 5.36 Mb and harbors approximate 4,913 genes, which will provide further insight into the synthesis of antimicrobial agents and antagonistic mechanisms of P. flavipulchra against pathogens.

Clinical use of probiotics in pediatrics.

Clinical use of probiotics in pediatrics.

Structures of Novel Antimicrobial Agents for Textiles - A Review

In this article we review some of the contemporary antimicrobial agents used in textiles, including quaternary ammonium compounds, N-halamines, chitosan, polybiguanides, triclosan, nanoparticles of noble metals and metal oxides, and bioactive plant-based products. According to their mechanism of antimicrobial activity, toxicity, durability and ecological acceptability, these agents can be divided into biocides and biostats, leaching and bound antimicrobials, controlled-release and barrier-forming agents, and agents of poor and good washing resistance. In view of the need for ecologically friendly antimicrobial finishing, much research has focused on the synthesis of antimicrobial agents where the leaching antimicrobials have been replaced with the bound antimicrobials. The latter have mostly been prepared using polymerizable quaternary ammonium salts with acrylate groups, alkyltrialkoxysilanes with incorporated quaternary ammonium groups, reactive cationic dyes, appropriate crosslinking agents, complexes with cyclodextrines, and encapsulated nanoparticle agents embedded into polymer matrices of various compositions.

Synthesis of antimicrobial agents. 5. In vivo metabolism of 7-(4-hydroxypiperazin-1-yl)quinolones.

A series of novel pyridone carboxylic acids having a 4-hydroxypiperazin-1-yl, a 4-hydroxy-3-methylpiperazin-1-yl, and a 4-hydroxy-3,5-dimethylpiperazin-1-yl group was prepared, and their metabolism to corresponding piperazinyl derivatives after oral administration to mice and rats was studied. This reductive metabolism appeared to be more extensive in mice than in rats. Moreover, the introduction of a methyl group into the alpha-position of the 4-hydroxy group depressed the metabolism in both species.

Synthesis of antimicrobial agents. 3. Syntheses and antibacterial activities of 7-(4-hydroxypiperazin-1-yl)quinolones

A series of novel pyridone carboxylic acids having a 4-hydroxypiperazinyl group at the 7-position of norfloxacin and ciprofloxacin were prepared. The in vivo antibacterial efficacies of these compounds were superior to those of corresponding piperazinyl derivatives. From the results of the studies on the pharmacokinetic profile and toxicity, the 4-hydroxypiperazinyl derivatives were confirmed to be pharmacologically superior to corresponding piperazinyl derivatives. Thus, a 4-hydroxypiperazinyl group was revealed to be a beneficial substituent for potential use in future quinolone antibacterials.

ChemInform Abstract: Synthesis of Antimicrobial Agents. Part 4. Synthesis of 1‐Hydroxypiperazine (V) Dihydrochloride and Its Applications to Pyridone Carboxylic Acid Antibacterial Agents (VII).

AbstractThe cyclopropyl derivative (VII) shows the most potent antibacterial activity.

Synthesis of antimicrobial agents. IV. synthesis of 1‐hydroxypiperazine dihydrochloride and its applications to pyridone carboxylic acid antibacterial agents

Abstract1‐Hydroxypiperazine dihydrochloride 7 was prepared and it was applied to the syntheses of new pyridone carboxylic acid antibacterial agents (PCA‐antibacterial agents). 1‐Cyclopropyl‐6,8‐difluoro‐1,4‐dihydro‐7‐(4‐hydroxypiperazin‐1‐yl)‐4‐oxoquinoline‐3‐carboxylic acid 13 showed the most potent antibacterial activity.

ChemInform Abstract: Synthesis of Antimicrobial Agents. Part 1. Syntheses and Antibacterial Activities of 7‐Azole Substituted Quinolones.

AbstractThe 7‐azole substituted quinolonecarboxylic acids (III) and (V) are prepared by nucleophilic substitution reactions of the trifluorocarboxylic acid (I) with the appropriate N‐nucleophiles.

ChemInform Abstract: Synthesis of Antimicrobial Agents. Part 2. Syntheses and Antibacterial Activities of Optically Active 7‐(3‐Hydroxypyrrolidin‐1‐yl)quinolones (III) and (V).

ChemInform Abstract: Synthesis of Antimicrobial Agents. Part 2. Syntheses and Antibacterial Activities of Optically Active 7‐(3‐Hydroxypyrrolidin‐1‐yl)quinolones (III) and (V).

Synthesis of antimicrobial agents. 1. Syntheses and antibacterial activities of 7-(azole substituted)quinolones.

A series of 6-fluoro- and 6,8-difluoro-7-(azole substituted)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids were prepared. Structure-activity relationship studies indicated that the antibacterial potency was better when the 6,8-substituents were fluorine atoms and the 7-substituent was either 1-imidazolyl, 20, or 4-methyl-1-imidazolyl, 25. From the results of studies on pharmacokinetic profile and toxicity, 20 and 25 were found to possess excellent antibacterial activities and to show high blood levels after oral administration to mice with low toxicity.

Synthesis of antimicrobial agents. II. Syntheses and antibacterial activities of optically active 7‐(3‐hydroxypyrrolidin‐1‐yl)quinolones

AbstractTwo optically active isomers of 1‐ethyl‐6,8‐difluoro‐1,4‐dihydro‐7‐(3‐hydroxypyrrolidin‐1‐yl)‐4‐oxoquinoline‐3‐carboxylic acid (10) were prepared. One of the isomer, 7‐[(3S)‐hydroxypyrrolidin‐1‐yl] derivative 8, was about 4 times more potent in vitro than the other, 7‐[(3R)‐hydroxypyrrolidin‐1‐yl] derivative 4, and approximately two times more active than the racemate, 7‐[(3RS)‐hydroxypyrrolidine‐1‐yl] derivative 10.Optical active 8 was the most active in in vivo, followed by 10, and 4 was the least active compound. But, they were more potent than CI‐934 12 and norfloxacin.From the results, (3S)‐hydroxypyrrolidinyl group was found to be one of the beneficial group for PCA‐anti‐bacterial agent.

Synthesis of antimicrobial agents. VI. Studies on the synthesis of furo[3,2-b][1,8]naphthyridine derivatives.

As a part of our search for new antibacterial agents, 5-ethyl-8-oxo-5, 8-dihydrofuro [3, 2-b]-[1, 8] naphthyridine-7-carboxylic acid and its 2, 3-dihydrofuro derivative, the 4-aza analogue of droxacin, were synthesized and their antibacterial activities were tested. Both compounds exhibited high antibacterial activities and a broad antibacterial spectrum. In an attempt to find a suitable method for industrial-scale synthesis of these compounds, several methods for the furan ring cyclization of 6, 7-disubstituted 1, 8-naphthyridine-3-carboxylate derivatives were compared.

Synthesis of antimicrobial agents. VII. Synthesis and antibacterial activities of furo [2,3-g]quinoline derivatives.

Les compose etudies sont des benzofuro-1 [4,5,6-ij] quinolizines et des furo [2,3-h] pyrido [1,2,3-de] benzooxazines-1,4

Synthesis of antimicrobial agents. V. Synthesis and antimicrobial activities of some heterocylic condensed 1,8-naphthyridine derivatives.

In order to search for compounds with higher activity than thiazolo [5, 4-b], imidazo-[4, 5-b] and triazolo [4, 5-b] [1, 8] naphthyridine derivatives against Ps. aeruginosa, we synthesized some heterocyclic condensed 1, 8-naphthyridine derivatives by using bifunctional 6, 7-disubstituted 1, 8-naphthyridine as a starting material. Thiadiazolo [5, 4-b] and oxazolo [5, 4-b] [1, 8] naphthyridine derivatives (3) and (5) were prepared by hydrolysis of the 6-amino-7-chloro-3-ester (1) with sodium hydroxide or sodium hydrosulfide, followed by cyclization with acetic anhydride or sodium nitrite. Pyrazolo [3, 4-b] and isothiazolo [5, 4-b] [1, 8] naphthyridine derivatives (12) and (14) were synthesized by ring cyclization of the 7-chloro-6-formyl-3-ester (10) with methyl hydrazine or ethanolic ammonia in the presence of sulfur, followed by hydrolysis. Thieno and furo [2, 3-b] [1, 8] naphthyridine derivatives (20) and (31) were prepared through a series of reaction steps, e.g. diazotization, reduction of the nitrile ester (7) or (24), ring cyclization by means of ethyl mercaptoacetate or ethyl bromomalonate, hydrolysis and decarboxylation. The compounds obtained were tested for antimicrobial activities in vitro. 8-Ethyl-5, 8-dihydro-5-oxothieno [2, 3-b] [1, 8] naphthyridine-6-carboxylic acid (20) exhibited the highest activities among these compounds against many gram-negative bacteria, including Ps. aeruginosa, and against gram-positive bacteria.

Synthesis of antimicrobial agents. IV. Synthesis and antimicrobial activities of imidazo[4,5-b][1,8]naphthyridine derivatives.

As part of a search for new antimicrobial agents, some 3, 5-disubstituted 5, 8-dihydro-8-oxoimidazo and triazolo [4, 5-b] [1, 8] naphthyridine-7-carboxylic acids and related compounds, which contain a new ring system, were prepared. The reactions of 6-amino-7-alkylamino-1-ethyl-1, 4-dihydro-4-oxo-1, 8-naphthyridine derivatives (3, 7, 11, 12 and 35) with acid, acetic anhydride, ethyl orthoformate and ethylxanthate afforded several imidazo [4, 5-b] [1, 8] naphthyridine derivatives. Treatment of the diamines (11 and 12) with sodium nitrite gave the triazolo [4, 5-b] [1, 8] naphthyridine derivatives (15 and 16). Reaction of the 7-acetylamino-4-hydroxy-1, 8-naphthyridine-3-carboxylate (17) with 1, 2-bromochloroethane gave different products (24 and 27), depending upon the reaction conditions. 3-Methyl-5-vinyl-5, 8-dihydro-8-oxoimidazo [4, 5-b] [1, 8]naphthyridine-7-carboxylic acid (38) was prepared by successive chloroethylation, nitration, chlorination, substitution with methylamine, reduction of the nitro group, imidazole cyclization and elimination of hydrogen chloride with simultaneous hydrolysis of the ester group. Some compounds obtained in this work showed activity nearly equal to that of pipemidic acid, but were slightly less active against Ps. aeruginosa.

Synthesis of antimicrobial agents. III. Synthesis and antimicrobial activities of thiazolo[5,4-b]naphthyridine derivatives.

In order to search for new antimicrobial agents, a number of 2-substituted 8-ethyl-5, 8-dihydro-5-oxothiazolo [5, 4-b] naphthyridine-6-carboxylic acid and their related compounds which consist of a new ring system were prepared. Reactions of the 6-amino-1-ethyl-7-mercapto-1, 4-dihydro-4-oxonaphthyridine-3-carboxylic acid (2) with acid, acid anhydride, acid chloride and ethylxanthate afforded several thiazolo [5, 4-b] naphthyridine derivatives. Refluxing ethyl 7-chloro-1-ethyl-6-nitro-1, 4-dihydro-4-oxonaphthyridine-3-carboxylate (16) with KSCN in acetic acid gave directly the thiazole cyclization product 19. Reaction of 8-ethyl-2-methylthio-5, 8-dihydro-5-oxothiazolo [5, 4-b] naphthyridine-6-carboxylic acid (11) with dimethyl sulfate gave various products (13b, 25 and 26) depending upon its reaction conditions. Some compounds obtained in this work exhibited high activities against gram-negative and gram-positive bacteria in vitro.

Synthesis of antimicrobial agents. I. Synthesis and antimicrobial activities of thiazoloquinoline derivatives.

A series of substituted thiazolo [4, 5-g]-, [5, 4-g]-, [4, 5-h]-and [5, 4-h] quinoline carboxylic acids has been prepared by the following two methods with the aim of providing new antimicrobial drugs. One of the synthetic methods has been carried out through successive steps of condensation of aminobenzothiazole with diethyl ethoxymethylenemalonate, Gould-Jacobs reaction, N-alkylation and hydrolysis. The other is thiazole ring cyclization of ortho-aminated mercaptoquinoline. These compounds prepared in this work were evaluated for antimicrobial activities in vitro. 9-Chloro-8-ethyl-5, 8-dihydro-5-oxothiazolo-[4, 5-g] quinoline-6-carboxylic acid (28b) showed the highest activity.