Carbazole Derivatives as Potential Antimicrobial Agents

Microbial infection is a leading cause of death worldwide, resulting in around 1.2 million deaths annually. Due to this, medicinal chemists are continuously searching for new or improved alternatives to combat microbial infections. Among many nitrogen-containing heterocycles, carbazole derivatives have shown significant biological activities, of which its antimicrobial and antifungal activities are the most studied. In this review, miscellaneous carbazole derivatives and their antimicrobial activity are discussed (articles published from 1999 to 2022).     

Synthesis and Antimicrobial Evaluation of Some New Thiophene Derivatives

2-(2-Cyano-acetylamino)-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carboxamide(3) was used as starting material for synthesis of 4-thiazolidinone, thiazolidine, and thiophene derivatives 6, 7a, b, and 8a, b, respectively. Thiocarbomyl derivative 5, 4-thizolidinone 9, and thioxothiazolidine 10 were obtained from reaction of 3 with thioglycolic acid and phenyl isothiocyanate/sulfur, respectively. Condensation of 3 with selected cyclic ketones and aromatic aldehydes yielded the arylidine derivatives 11a, b and 13, respectively. Refluxing of 11a, b with sulfur and morpholine yielded the thiophene derivatives 12a, b, respectively. Diazocoupling of compound 3 withp-tolyl diazonium chloride yielded the hydrazone derivative 14. The newly synthesized compounds were characterized by infrared, ¹H NMR, and mass spectral studies. Representative compounds of the synthesized product were tested and evaluated as antimicrobial agents. Compound 12b gives very high antimicrobial activity against Ampicillin.     

Synthesis and Application of Some New Thienopyrimidine Derivatives as Antimicrobial Agents

The paper describes the synthesis of new ring system 5-phenylthieno[2,3-d]pyrimidine-4(3H)one (2). Chlorination of (2) with PCl₅, POCl₃ gave the corresponding 4-chloro derivative (4). Several derivatives of the latter compound have been synthesised and tested for antimicrobial activity.     

Synthesis of Novel Quinazoline Derivatives as Antimicrobial Agents

Quinazoline isothiocyanate 1 reacts with various nucleophiles(nitrogen nucleophiles,oxygen nucleophiles and sulphur nucleophiles)to afford heterocyclic systemes 2-13,Also,the [4 2] cycloaddition reaction of 1 with phenyl isocyanate,benzylidene aryl amine and cinnamic acid derivatives gave novel heterocyclic compounds 14-16,Moreover,the reaction of 1 with active methylene compounds under Michael reaction conditions also was investigated to yield 17 and 18 and it was found that all these reactions proceede via isothiocyanate heterocyclization to furnish non-condensed heterocyclic compoundes,Some of the newly synthesized compounds were tested for their antimicrobial activities.     

Synthesis of Thiazolidine and Thiophene Derivatives for Evaluation as Anticancer Agents

The non-isolated adducts (3a,b) were used as key intermediates to synthesize some novel thiazolidine and thiophene derivatives. Compound (4) exhibited a remarkable antitumor activity against EAC cells compared with the Doxorubicin as a positive control.     

Synthesis of Polyfunctionally Substituted Fused Pyrimidine Derivatives as Antimicrobial Agents

A variety of pyrimidine derivatives 2—4 and annulated pyrimidine derivatives 5—17 have been synthesized via a sequence of heterocyclization reaction of readily available 6-naphthyl-4-oxo-2-thioxo-1,2,3,4-tetrahydroprimi-     

Synthesis of Some New Substituted Thieno[2,3-d]pyrimidine Derivatives as Antimicrobial Agents

Russian Journal of General Chemistry - A series of thieno-pyrimidine derivatives are synthesized from 5′-amino-2,3′-bithiophene-4′-carboxylate via the corresponding intermediate...     

Transition Metal Complexes of Azo-8-Hydroxyquinoline Derivatives as Antimicrobial Agents

Some New azo sulphonamide derivatives containing 8-hydroxyquinoline moiety and their complexes with some transition metal ions vz. Fe⁺³, Co⁺², Ni⁺², Cu⁺², and Hg⁺² have been prepared and characterised. The stereochemistry as well as the type of bonding around the metal ions were determined on the basis of microanalysis, IR and UV-VIS spectra, conductivity and magnetic moment measurements; the thermal behaviour of the complexes was also studied. The metal ions coordinate exclusively to the 8-hydroxyquinoline moiety. The biological activity of the complexes was tested against a number of bacteria. Chelation of the metal ions to the ligands induces a remarkable increase in their antimicrobial activity.     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.     

New Thiophene Derivatives with Two-photon Excited Fluorescence

Organic molecules that can simultaneously absorb two or more photons in reaching theirexcited states have recently been the subject in various photon-electronic fields. Tomeet the criteria for various nonlinear optical applications, such as three-dimensionaloptical storage1 and up-converted lasing2, molecules with large two-photon absorption(TPA) cross-section σ are required and have been synthesized. These dyes generallybelong to the structural modes of D-π-D, A-π-A3 or D-π-A, where D…     

Synthesis and Reactions of Some New Quinazoline Derivatives for In Vitro Evaluation as Anticancer and Antimicrobial Agents

A novel series of N,O,S heterocyclic compounds incorporated at position‐3 of a quinazolin‐4(3H)‐one moiety were synthesized through a p‐phenloxy binding including oxadiazolethione pyridazinetrione, thiazolidinedione, benzothiazindione, and quinazolinedione. New carbamates, urea derivatives, and Mannich bases were also prepared for the purpose of in vitro anticancer cell lines evaluation and cytotoxic activity. The key intermediate 2‐(4‐chlorophenyl)‐3‐(4‐hydroxyphenyl)quinazolin‐4(3H)‐one was prepared from the reaction of 4H‐benzo [d][3,1]oxazin‐4‐one and a nitrogenous nucleophilic compound, 4‐aminophenol. Some of the newly synthesized compounds showed significant cytotoxic activity.     

Syntheses of New Isocephems and Isodethiaoxacephems as Antimicrobial Agents

The cis-configurated isocephem 26 as well as isodethiaoxacephems 21 and 33 were synthesized (Schemes 4 and 5). The key step involves chlorination of the corresponding carbanions of 23, 18 , and 31 with CF₃SO₂Cl followed by internal alkylation. β-Lactams 3, 21, 26 , and 33 were found to possess biological activity against several pathogenic microorganisms in vitro. Electronic activation of the lactam moiety in isodethiaoxacephem 33 remarkably enhanced its biological activity.     

Synthesis of Tetradentate Schiff Base Derivatives of Transition Bimetallic Complexes as Antimicrobial Agents

A series of Co(II), Cu(II), Mn(II) and Zn(II) bimetallic complexes have been synthesized with the schiff base ligand 2‐(bis‐2‐hydroxyl phenylidene) diimine (L) derived from the condensation of hydrazine and salicylaldehyde. The synthesized ligand and bimetallic complexes were characterized by different spectroscopic techniques. The characterization of ligand was carried out by FT‐IR, H¹NMR, C¹³NMR and MS while the bimetallic complexes were characterized by FT‐IR and X‐ray crystallographic techniques. The complexes and ligand were employed in vitro for antifungal and antibacterial activities using disc diffusion method. Different fungal strains such as Alternaria Alternate, Aspergillus Flavus and Aspergillus Niger were used to check antifungal activities of bimetallic complexes and ligand. Similarly, the bacterial strains used were Staphylococcus Aureus, Bacillus Subbtilis and Escheria Coli. The biological studies showed that the ligand exhibited lower value of antifungal and antibacterial activities than bimetallic complexes.     

Synthesis of Novel 3-Substituted Pyridothienopyrimidine Derivatives with Biological Evaluation as Antimicrobial Agents

Novel 3-substituted pyridothienopyrimidine derivatives have been synthesized via the reaction of 2-{7,9-dimethyl-4-oxopyrido[3',2':4,5]thieno[3,2-d]pyrimidin-3(4H)-yl}acetohydrazide(5) with a variety of active reagents and chemicals. Structures of the newly synthesized compounds were established based on spectral data. The resulting pyridothienopyrimidine derivatives were evaluated for their possible antimicrobial activity and some of them represent a new class of potentially antimicrobial compounds, especially compounds 9 and 18 which displayed the highest activity against Gram-positive bacteria, Gram-negative bacteria, and Fungi in MIC range of 0.12-1.95 μg/mL.     

The Syntheses of New Cyclopenta[d][1,3]thiazine Derivatives and Their Use as Antimicrobial Agents

Cyclopentanone (1) was exploited as a starting material for the syntheses of hitherto unknown cyclopenta[d][1,3]thiazine derivatives.     

Synthesis of Some New Ciprofloxacin Hybrids as Potential Antimicrobial Agents

A new series of ciprofloxacin hybrid compounds as new type of antimicrobial agents were synthesized and evaluated for antibacterial activity against Gram‐positive and Gram‐negative bacteria.