Synthesis, crystal structure, molecular docking and antimicrobial evaluation of new pyrrolo[3,2-c]pyridine derivatives

The Structure-Antiproliferative Activity Relationship of Pyridine Derivatives

Pyridine, a compound with a heterocyclic structure, is a key player in medicinal chemistry and drug design. It is widely used as a framework for the design of biologically active molecules and is the second most common heterocycle in FDA-approved drugs. Pyridine is known for its diverse biological activity, including antituberculosis, antitumor, anticoagulant, antiviral, antimalarial, antileishmania, anti-inflammatory, anti-Alzheimer's, antitrypanosomal, antimalarial, vasodilatory, antioxidant, antimicrobial, and antiproliferative effects. This review, spanning from 2022 to 2012, involved the meticulous identification of pyridine derivatives with antiproliferative activity, as indicated by their minimum inhibitory concentration values (IC50) against various cancerous cell lines. The aim was to determine the most favorable structural characteristics for their antiproliferative activity. Using computer programs, we constructed and calculated the molecular descriptors and analyzed the electrostatic potential maps of the selected pyridine derivatives. The study found that the presence and positions of the -OMe, -OH, -C=O, and NH2 groups in the pyridine derivatives enhanced their antiproliferative activity over the cancerous cellular lines studied. Conversely, pyridine derivatives with halogen atoms or bulky groups in their structures exhibited lower antiproliferative activity.

An efficient domino strategy for synthesis of 3-substituted 4-oxo-4,5-dihydro-1H-pyrrolo[3,2-c]pyridine derivatives in water

A strategy for catalyst-free domino reaction of 4-aminopyridin-2(1H)-ones, arylglyoxal hydrates and different 1,3-dicarbonyl compounds in water has been established. The mild and efficient procedure afforded pyrrolo[3,2-c]pyridine derivatives with 76-94% yields after simple crystallization. The present procedure shows promising characteristics, such as readily available starting materials, the use of water as reaction media, simple and efficient one-pot operation, and avoiding the need for any hazardous or expensive catalysts.

Application of Fluorine- and Nitrogen-Walk Approaches: Defining the Structural and Functional Diversity of 2-Phenylindole Class of Cannabinoid 1 Receptor Positive Allosteric Modulators

Cannabinoid 1 receptor (CB1R) allosteric ligands hold a far-reaching therapeutic promise. We report the application of fluoro- and nitrogen-walk approaches to enhance the drug-like properties of GAT211, a prototype CB1R allosteric agonist-positive allosteric modulator (ago-PAM). Several analogs exhibited improved functional potency (cAMP, β-arrestin 2), metabolic stability, and aqueous solubility. Two key analogs, GAT591 (6r) and GAT593 (6s), exhibited augmented allosteric-agonist and PAM activities in neuronal cultures, improved metabolic stability, and enhanced orthosteric agonist binding (CP55,940). Both analogs also exhibited good analgesic potency in the CFA inflammatory-pain model with longer duration of action over GAT211 while being devoid of adverse cannabimimetic effects. Another analog, GAT592 (9j), exhibited moderate ago-PAM potency and improved aqueous solubility with therapeutic reduction of intraocular pressure in murine glaucoma models. The SAR findings and the enhanced allosteric activity in this class of allosteric modulators were accounted for in our recently developed computational model for CB1R allosteric activation and positive allosteric modulation.

Synthesis, molecular docking, antimycobacterial and antimicrobial evaluation of new pyrrolo[3,2-c]pyridine Mannich bases

In this report, we describe the synthesis and biological evaluation of a new series of pyrrolo[3,2-c]pyridine Mannich bases (7a-v). The Mannich bases were obtained in good yields by one-pot three component condensation of pyrrolo[3,2-c]pyridine scaffold (6a-c) with secondary amines and excess of formaldehyde solution in AcOH. The chemical structures of the compounds were characterized by ¹H NMR, ¹³C NMR, LC/MS and elemental analysis. Single crystal X-ray diffraction has been recorded for compound 7k ([C₂₃H₂₉ClN₄]⁺², H₂O). The in vitro antimicrobial activities of the compounds were evaluated against various bacterial and fungal strains using Agar diffusion method and Broth micro dilution method. Compounds 7e, 7f, 7r, 7t, and 7u were showed good Gram-positive antibacterial activity against S. aureus, B. flexus, C. sporogenes and S. mutans. Furthermore, in vitro antimycobacterial activity was evaluated against Mycobacterium tuberculosis H37Rv (ATCC 27294) using MABA. Compounds 7r, 7t, and 7u were showed good antitubercular activity against Mtb (MIC ≥6.25 μg/mL). Among the tested compounds, 1-((4-chloro-2-(cyclohexylmethyl)-1H-pyrrolo[3,2-c]pyridin-3-yl)methyl)piperidine-3-carboxamide (7t) was showed excellent antimycobacterial activity against Mtb (MIC <0.78 μg/mL) and low cytotoxicity against the HEK-293T cell line (SI >>25). Molecular docking of the active compounds against glutamate racemase (MurI) and Mtb glutamine synthetase were explained the structure-activity observed in vitro.

Synthesis and trypanocidal activity of a library of 4-substituted 2-(1H-pyrrolo[3,2-c]pyridin-2-yl)propan-2-ols

A library of 16 4-substituted 2-(1H-pyrrolo[3,2-c]pyridin-2-yl)propan-2-ols 17-32 has been synthesized for use in biological testing against Trypanosoma cruzi, the protozoan parasite that causes Chagas disease. The 4-substituted 2-(1H-pyrrolo[3,2-c]pyridin-2-yl)propan-2-ols 17-32 were subjected to biological testing to evaluate their efficacy against intracellular Trypanosoma cruzi (Y strain) amastigotes infecting U2OS human cells, with benznidazole as a reference compound. The assay was performed in duplicate (two independent experiments) and submitted to High Content Analysis (HCA) for determination of trypanocidal activity. Three of the tested compounds presented relatively high trypanocidal activity (19, 22 and 29), however severe host cell toxicity was observed concomitantly. Chemical optimization of the highly active compounds and the synthesis of more compounds for biological testing against Trypanosoma cruzi will be required to improve selectivity and so that a structure-activity relationship can be generated to provide a more insightful analysis of both chemical and biological aspects.

Optical properties and fluorescence quenching of biologically active ethyl 4-(4-N,N-dimethylamino phenyl)-2-methyl-5-oxo-4,5-dihydro-1H-indeno[1,2-b]pyridine-3-carboxylate (DDPC) dye as a probe to determine CMC of surfactants

4-(4-N,N-Dimethylamino phenyl)-2-methyl-5-oxo-4,5-dihydro-1H-indeno[1,2-b]pyridine-3-carboxylate (DDPC) was prepared via the multi-component reaction of indane-1,3-dione with 4-(dimethylamino)benzaldehyde, ethyl acetoacetate and ammonium acetate.