N/C-4 substituted azetidin-2-ones: Synthesis and preliminary evaluation as new class of antimicrobial agents

Novel (±)-trans-β-lactam ureas: Synthesis, in silico and in vitro biological profiling

A diastereomeric mixture of racemic 3-phthalimido-b-lactam 2a/2b was synthesized by the Staudinger reaction of carboxylic acid activated with 2-chloro-1-methylpyridinium iodide and imine 1. The amino group at the C3 position of the b-lactam ring was used for further structural upgrade. trans-b-lactam ureas 4a-t were prepared by the condensation reaction of the amino group of b-lactam ring with various aromatic and aliphatic isocyanates. Antimicrobial activity of compounds 4a-t was evaluated in vitro and neither antibacterial nor antifungal activity were observed. Several of the newly synthesized trans-b-lactam ureas 4a-c, 4f, 4h, 4n, 4o, 4p, and 4s were evaluated for in vitro antiproliferative activity against liver hepatocellular carcinoma (HepG2), ovarian carcinoma (A2780), breast adenocarcinoma (MCF7) and untransformed human fibroblasts (HFF1). The b-lactam urea 4o showed the most potent antiproliferative activity against the ovarian carcinoma (A2780) cell line. Compounds 4o and 4p exhibited strong cytotoxic effects against human non-tumor cell line HFF1. The b-lactam ureas 4a-t were estimated to be soluble and membrane permeable, moderately lipophilic molecules (logP 4.6) with a predisposition to be CYP3A4 and P-glycoprotein substrates. The tools PASS and SwissTargetPrediction could not predict biological targets for compounds 4a-t with high probability, pointing to the novelty of their structure. Considering low toxicity risk, molecules 4a and 4f can be selected as the most promising candidates for further structure modifications.

Novel Benzotriazole-β-lactam Derivatives as Antimalarial Agents: Design, Synthesis, Biological Evaluation and Molecular Docking Studies

Many people around the world suffer from malaria, especially in tropical or subtropical regions. While malaria medications have shown success in treating malaria, there is still a problem with resistance to these drugs. Herein, we designed and synthesized some structurally novel benzotriazole-β-lactams using 2-(1H-benzo[d][1,2,3]triazol-1-yl)acetic acid as a key intermediate. To synthesize the target molecules, the ketene-imine cycloaddition reaction was employed. First, The reaction of 1H-benzo[d][1,2,3]triazole with 2-bromoacetic acid in aqueous sodium hydroxide yielded 2-(1H-benzo[d][1,2,3]triazol-1-yl)acetic acid. Then, the treatment of 2-(1H-benzo[d][1,2,3]triazol-1-yl)acetic acid with tosyl chloride, triethyl amine, and Schiff base provided new β-lactams in good to moderate yields.The formation of all cycloadducts was confirmed by elemental analysis, FT-IR, NMR and mass spectral data. Moreover, X-ray crystallography was used to determine the relative stereochemistry of 4a compound. The in vitro antimalarial activity test was conducted for each compound against P. falciparum K1. The IC50 values ranged from 5.56 to 25.65 μM. A cytotoxicity profile of the compounds at 200 μM final concentration revealed suitable selectivity of the compounds for malaria treatment. Furthermore, the docking study was carried out for each compound into the P. falciparum dihydrofolate reductase enzyme (PfDHFR) binding site to analyze their possible binding orientation in the active site.

Synthesis and biological evaluation of substituted phenyl azetidine-2-one sulphonyl derivatives as potential antimicrobial and antiviral agents

In the present study, we intend to synthesize a series of novel substituted phenyl azetidine-2-one sulphonyl derivatives. The entire set of derivatives 5 (a-t) were screened for in-vitro antibacterial, and antifungal activity, and among them eleven compounds were further screened for the antiviral activity to predict their efficacy against pathogenic viruses. Interestingly, compound 5d, 5e, 5f, 5h, 5i, and 5j showed similar or better antibacterial activity as compared to ampicillin (standard). Moreover, compounds 5h, 5i, 5j, and 5q showed good inhibitory activity against fungal strains whereas other derivatives had mild or diminished activity in comparison with standard drug clotrimazole. The antimicrobial study indicated that compounds having electron-withdrawing groups showed the highest activity. Interestingly, these tested compounds showed weak antiviral activity against Vaccinia virus, Human Coronavirus (229E), Reovirus-1, Herpes simplex virus, Sindbis virus, Coxsackievirus B4, Yellow Fever virus, and Influenza B virus in HEL cell, Vero cell, and MDCK cell cultures. The findings of the present study might open new avenues to target human disease-causing deadly microbes and viruses.

Synthesis and In Silico Molecular Docking Studies on Substituted Piperic Acid Derivatives as Inhibitors of Bacterial DNA Gyrase

Background:

Piperine or piperic acid was isolated from fruits of Piper nigrum and had been reported as pharmacological valuable bioactive constituents. Keeping in view, a series of piperic acid-based N heterocyclic’s derivatives were synthesized and evaluated for antibacterial activity. All these prepared ligands were docked to study the molecular interactions and binding affinities against the protein PDB ID: 5 CDP.

Objective:

To meet the real need of newer antibacterials, we designed and synthesized scaffolds with good antibacterial activity. The obtained antibacterials have been validated in terms of ligand-protein interaction and thus prove to build up as good drug candidates.

Methods:

Antibacterial activity of the compounds were carried out against bacterial strains; three Grampositive and three Gram-negative bacterial strains using agar well diffusion method. In silico molecular docking studies were carried out using Glide (grid-based ligand docking) program incorporated in the Schrödinger molecular modeling package by Maestro 11.0.

Results:

Compounds BC 28, BC 32, and BC 33 exhibits antibacterial activity along with Glide docking score of -8.580, -9.753 kcal/mol, and -8.813 kcal/mol, respectively. Docking studies explained hydrogen bonding, pi-pi, and hydrophobic interactions with amino acid residues which explain the binding affinity of the most docked ligand with protein.

Conclusion:

In the present study, substituted piperic acid was synthesized and evaluated as antibacterial compared with standard drug ciprofloxacin and results interpret that having nitrogen as heteroatom in the heterocyclic nucleus found to be more potent than the standard drug ciprofloxacin. On comparing, substitution with electron-donating groups generates excellent antibacterial potential against the bacterial strains. It was also proved that having substitution with electron-donating groups on meta and para position with triazoline ring system exhibits greater potential while compounds which have a meta- electron-donating substituent showed lesser activity with thiazole nucleus. In addition, structure-based activities of the prepared analogs were discussed under Structure-Activity Relationship (SAR) section.

Synthesis and biological evaluation of new fluconazole β-lactam conjugates linked via 1,2,3-triazole

Novel fluconazole conjugates with potent antifungal activity are reported here. They were also found to be non-hemolytic and non-cytotoxic.

Synthesis and characterization of β-lactam functionalized superparamagnetic Fe3O4@SiO2 nanoparticles as an approach for improvement of antibacterial activity of β-lactams

Preparation of magnetic β-lactam functionalized Fe₃O₄@SiO₂ nanoparticles has a synergic effect to improve the antibacterial activity.

Bioactivity Studies of β-Lactam Derived Polycyclic Fused Pyrroli-Dine/Pyrrolizidine Derivatives in Dentistry: In Vitro, In Vivo and In Silico Studies

The antibacterial activity of β-lactam derived polycyclic fused pyrrolidine/pyrrolizidine derivatives synthesized by 1, 3-dipolar cycloaddition reaction was evaluated against microbes involved in dental infection. Fifteen compounds were screened; among them compound 3 showed efficient antibacterial activity in an ex vivo dentinal tubule model and in vivo mice infectious model. In silico docking studies showed greater affinity to penicillin binding protein. Cell damage was observed under Scanning Electron Microscopy (SEM) which was further proved by Confocal Laser Scanning Microscope (CLSM) and quantified using Flow Cytometry by PI up-take. Compound 3 treated E. faecalis showed ROS generation and loss of membrane integrity was quantified by flow cytometry. Compound 3 was also found to be active against resistant E. faecalis strains isolated from failed root canal treatment cases. Further, compound 3 was found to be hemocompatible, not cytotoxic to normal mammalian NIH 3T3 cells and non mutagenic. It was concluded that β-lactam compound 3 exhibited promising antibacterial activity against E. faecalis involved in root canal infections and the mechanism of action was deciphered. The results of this research can be further implicated in the development of potent antibacterial medicaments with applications in dentistry.

The chemistry and biological potential of azetidin-2-ones

Azetidin-2-ones, commonly referred as β-lactams, represent a unique ring system, with interesting chemistry and great biological potential. Besides its well known antibiotic activity, this ring system exhibits a wide range of activities, attracting the attention of researchers. The biological and pharmacological profile of azetidin-2-ones is reviewed here comprehensively with several examples under fourteen different activity heads. The chemistry and methods of synthesis have also been discussed.

Synthesis, Antimicrobial and cytotoxic activity of New Heterocyclic Hybrids Based on 2,5-Dimethylpyrrole and Pyrrole Scaffolds

A series of 4-(2,5-dimethylpyrrol-1-yl)/4-pyrrol-1-yl benzoic acid hydrazide analogs, some derived triazoles, azetidinones, thiazolidinones, and pyrroles have been synthesized in good yields and structures of these compounds were established by IR, ¹H NMR, ¹³C NMR, mass spectral, and elemental analysis. These compounds were evaluated for their preliminary in vitro antibacterial, antifungal, and antitubercular activity against Mycobacterium tuberculosis H₃₇ Rv strain by the broth dilution assay method. Twenty one of these compounds displayed good antimicrobial activity, with a MIC value of 1-4 μg/ml. Several compounds 4c, 8-10, 15b-15h, and 16b-16d exhibited good in vitro antitubercular activity with MIC value 1-2 μg/ml. Further, some title compounds were also assessed for their cytotoxic activity (IC₅₀) against mammalian Vero cell lines and A₅₄₉ (lung adenocarcinoma) cell lines using the MTT assay method. The results revealed that these compounds exhibit antitubercular activity at non-cytotoxic concentrations.

Synthesis of 1H-1,2,3-triazole linked β-lactam-isatin bi-functional hybrids and preliminary analysis of in vitro activity against the protozoal parasite Trichomonas vaginalis

Twenty-two different triazoles were prepared to examine the anti-Trichomonas vaginalis structure-activity relationships (SAR) within the β-lactam-isatin-triazole conjugate family. The compounds were synthesized by copper-catalyzed 'click chemistry.'In vitro activity against T. vaginalis was determined at 10 and 100 μM for each compound, with eighteen of the synthesized hybrids showing 100% growth inhibition at 100 μM. The compound 5i, with no cytotoxicity on cultured CHO-K1 cells, is considered a good compound for further analysis.

2-Azetidinone--a new profile of various pharmacological activities

2-azetidinone, a β-lactam four member heterocyclic compound involved in research aimed to evaluate new products that possess interesting biological activities. These compounds reported for their antimicrobial and antifungal activities. Successful introduction of aztreonam as a potent inhibitor of cephalosporinase and ezetimibe as a cholesterol absorption inhibitor proved potential of 2-azetidinone moiety. Subsequently 2-azetidinones were highlighted as a potent mechanism based inhibitor of several enzymes like human tryptase, chymase, thrombin, leukocyte elastase, human cytomegalovirus protease and serine protease enzyme. These derivatives also known to possess antitubercular, anti-inflammatory, antitumor, anti-HIV, antiparkinsonian, antidiabetic and vasopressin V1a antagonist activity. The present review article focuses on the pharmacological profile of 2-azetidinones with their potential activities.

Synthesis of novel beta-lactam fused spiroisoxazolidine chromanones and tetralones as potent antimicrobial agent for human and plant pathogens

Synthesis of novel beta-lactam fused spiroisoxazolidine chromanones and tetralones ring systems has been achieved by intermolecular 1,3-dipolar cycloaddition reaction of bicyclic nitrone with unusual dipolarophiles, arylidene chromanones/tetralones under different reaction conditions. The synthesized compounds were evaluated for antimicrobial activities. It was observed that two of the synthesized compounds exhibited relatively good antibacterial and antifungal activities.

Synthesis and antifungal activity of 2-azetidinonyl-5-(2-benzoylphenoxy)methyl-1,3,4-oxadiazoles against seed-borne pathogens of Eleusine coracana (L.) Gaertn

BACKGROUND

Finger millet is a major food crop as well as feed and fodder for livestock, especially in regions of southern India. A sturdy crop to fluctuating environmental conditions, it can be cultivated in all seasons of the year. Leaf, neck and finger blast caused by Pyricularia grisea Sacc. and Bipolaris setariae (Saw.) Shoem, as well as leaf spot disease, Bipolaris nodulosa (Berk & M.A.Curtis) Shoem, are major production constraints in southern India. Apart from environmental conditions, the use of harvested seeds by farmers is a major reason for disease prevalence. Benzophenone analogues have been investigated for controlling phytopathogenic fungi. In addition, the most important applications of azetidin-2-ones are as antibiotics. Based on this information, the present study was conducted to explore the antifungal activity of integrated 2-azetidinonyl and 1,3,4-oxadiazoles moieties into a benzophenone framework.

RESULTS

A simple high-yielding method for the integration of heterocyclic rings, namely 2-azetidinonyl, at the benzophenone nucleus has been achieved, starting from substituted 2-hydroxybenzophenones under mild conditions on a wet solid surface using microwave irradiation. In the present study, an array of newly synthesised compounds, 2-azetidinonyl-5-(2-benzoylphenoxy)methyl-1,3,4-oxadiazoles, were screened for their antifungal property against blast and leaf spot causing fungi associated with the seeds of finger millet, cv. Indof-9.

CONCLUSION

Two of the newly synthesised compounds showed promising effects in depleting the incidence of seed-borne pathogenic fungi of finger millet. The suppression of Pyricularia grisea and Bipolaris setariae resulted in enhanced seed germination and seedling growth.

Ethyl 1'-[1-(4-methoxyphenyl)-3-phenoxy-4-phenylazetidin-1-yl]-1,3-dioxo-2′,3′,5′,6′,7′,7a′-hexahydroindan-2-spiro-3′-1′H-pyrrolizine-2′-carboxylate

In the title compound, C₃₄H₃₂N₂O₇, the methyl group and methylene H atoms of the ethoxycarbonyl substituent are disordered over two positions with site occupancy factors for the major and minor conformers of 0.594 (8) and 0.406 (8), respectively. The unsubstituted ring of the pyrrolizine ring system exhibits a twist conformation, the other an envelope conformation. In the crystal structure, mol­ecules are linked through C—H⋯O hydrogen bonds; intramolecular C—H⋯O interactions are also observed.

Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-beta-lactam

We report herein the synthesis and biological evaluation of bile acid dimers linked through 1,2,3-triazole and bis-beta-lactam. The dimers were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-beta-lactams , and terminal alkynes derived from cholic acid/deoxycholic acid in the presence of Cu(i) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7 cells were also established.

2-[1-(4-Ethoxy-phen-yl)-2-oxo-4-styryl-azetidin-3-yl]isoindoline-1,3-dione

The title compound, C₂₇H₂₂N₂O₄, contains a nearly planar four-membered β-lactam ring, which makes dihedral angles of 74.64 (12), 1.70 (11) and 73.67 (12)° with the nine-membered ring system, the benzene ring and the phenyl ring, respectively. The crystal structure is stabilized by C—H⋯O and C—H⋯π inter­actions and a π–π inter­action [centroid–centroid distance = 3.4505 (19) Å] is also present.

Synthesis and antimicrobial activity of beta-lactam-bile acid conjugates linked via triazole

Synthesis of novel 1,2,3-triazole-linked beta-lactam-bile acid conjugates 17-24 using 1,3-dipolar cycloaddition reaction of azido beta-lactam and terminal alkyne of bile acids in the presence of Cu(I) catalyst (click chemistry) have been realized. These molecules were evaluated in vitro for their antifungal and antibacterial activities. Most of the compounds exhibited significant antifungal and moderate antibacterial activity against all the tested strains.