Synthesis and Biological Properties of Coumarin Analogue: A Brief Review

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One of the most prominent aromatic organic chemical compound is Coumarin having formula C9H6O2 which is widely known for its benefits in drug industry. Colourless crystalline solid having sweet scent is coumarin’s physical identity. It serves various purposes such as in synthesis of medicines, laser dyes, perfumes and many more. Having enormous usages it becomes important to synthesize such compound so various reactions were performed in order to obtain coumarins. This review explicates the preparation of coumarin by Pechmann Condensation and its biological characteristics.

Synthesis of Substituted -N-(5-((7-Methyl-2-Oxo-2H-Chromen-4-yl)- Methyl)-1,3,4-Thiadiazol-2-yl)-Benzamide Derivatives Using TBTU as Coupling Agent and their Evaluation for Anti Tubercular Activity

Abstract:

Tuberculosis remains a highly infectious disease across the world. In the identification of new antitubercular agents, coumarin clubbed thiadiazole amides have been synthesized and evaluated for in vitro antitubercular activity. Owing to the growing concern of chemicals and their impact on the environment, greener and faster reaction conditions needed to be incorporated. Therefore, we used TBTU as a coupling reagent for efficient and facile synthesis of substituted-N-(5-((7-methyl-2-oxo-2Hchromes- 4-yl)-methyl)-1,3, 4-thiadiazol-2-yl)-benzamide 4a-j with good yields up to 95% in mild reaction conditions. All the synthesized compounds were evaluated in vitro for anti-tubercular activity against the H37Rv strain of M. tuberculosis. Compounds 4c, 4d, and 4f were found active at 12.5 μg/mL against M. tb H37Rv. Electron withdrawing substituents present on aromatic side chains showed promising anti-tubercular activity.

Visible light photocatalysis in the synthesis of pharmaceutically relevant heterocyclic scaffolds

Visible light and photoredox catalysis have emerged as a powerful and long-lasting tool for organic synthesis, demonstrating the importance of a variety of chemical bond formation methods.

Synthesis, cytotoxicity and in silico study of some novel benzocoumarin-chalcone-bearing aryl ester derivatives and benzocoumarin-derived arylamide analogs

The development of new prostate cancer protein receptor cytochrome P450 17A1 inhibitors offers the possibility of generating structures of increased potency. To this end, the chalcone analogs 7 and 8 were prepared from treatment of methyl 3-oxo-3H-benzocoumarin-2-carboxylate (4) with aryl aldehydes. Treatment of 7 and 8 with three anti-inflammatory drugs, flurbiprofen, ketoprofen and ibuprofen, in the presence of POCl3/DMAP gave the ester analogs 9–12. Analogously, treatment of ethyl 3-oxo-3H-benzocoumarin-2-carboxylate (15), prepared previously from 2-hydroxy-1-naphthaldehyde (13) and dimethylmalonate (14), with various arylamines: 4-bromoaniline, 2-amino-6-methylpyridine, amino-antipyrine and 2-amino-5-nitrothiazole, in the presence of potassium tert-butoxide gave the benzocoumarine-3-arylamide analogs. The in vitro cytotoxic activities of 9–12 and 16–19 were evaluated against human prostate cancer cell lines (PC-3) and normal human liver epithelia (WRL-68) by MTT assay. Compounds 10 and 17 were the most active cytotoxic agents among the series against PC-3 cells with IC50 values of 71.35 and 78.25 μg mL–1 with SI values of 3.0 and 4.2, respectively (calculated from the cytotoxicity effects of 10 and 17 on the normal human liver epithelia [WRL-68]). Furthermore, compounds 11 and 12 were tested against breast cancer (HER2 cell lines), prostate cancer (DU-135 cell lines) and MCF-7 but were inactive. Molecular docking studies between the protein receptor CYPP450 17A1 and compounds 10 and 17 revealed that these compounds primarily form hydrophobic interactions with the receptor.

A coumarin embedded highly sensitive nitric oxide fluorescent sensor: kinetic assay and bio-imaging applications

Fluorescence spectroscopy is a significant bio-analytical technique for specific detection of nitric oxide (NO) and for broadcasting the in vitro and in vivo biological activities of this gasotransmitter. Herein, a benzo-coumarin embedded smart molecular probe (BCM) is employed for NO sensing through detailed fluorescence studies in purely aqueous medium. All the spectroscopic analysis and literature reports clearly validate the mechanistic insight of this sensing strategy i.e., the initial formation of 1,2,3,4-oxatriazole on treatment of the probe with NO which finally converted to its carboxylic acid derivative. This oxatriazole formation results in a drastic enhancement in fluoroscence intensity due to the photoinduced electron transfer (PET) effect. The kinetic investigation unveils the second and first-order dependency on [NO] and [BCM] respectively. The very low detection limit (16 nM), high fluorescence enhancement (123 fold) in aqueous medium and good formation constant (Kf = (4.33 ± 0.48) × 104 M-1) along with pH invariability, non-cytotoxicity, biocompatibility and cell permeability make this probe a very effective one for tracking NO intracellularly.

Synthesis, characterization, anti-diabetic potential and DFT studies of 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde oxime

A new compound named 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde oxime (7-Oxime) was synthesized and characterized by FT-IR, FT-Raman, ¹H NMR and ¹³C NMR techniques. The conformer possibilities were studied to find the most stable conformer and its molecular geometry. Then, the dimer form of the most stable monomer was built and optimized. Density functional theory (DFT) B3LYP method with 6-311++G(d,p) basis set was applied to analyze the molecular electrostatic potential (MEP), HOMO and LUMO orbitals, the vibrational wavenumbers, the infrared intensities, the Raman scattering activities and several thermodynamic properties (at different temperatures). The stability of the molecule derived from hyperconjugative interactions and charge delocalization has been analyzed by using natural bond orbital (NBO) analysis. In order to find the possible inhibitory activity of 7-Oxime, an accurate molecular blind docking simulation was performed. The results indicated that the mentioned compound has a good binding affinity to interact with the active sites of human α-glucosidase and α-amylase. For the first time, our computational finding suggests that this compound has a potential to be used as a supplementary agent in the pre-management of diabetes mellitus.

Modulation of S. aureus and P. aeruginosa biofilm: an in vitro study with new coumarin derivatives

Coumarin is an important heterocyclic molecular framework of bioactive molecules against broad spectrum pathological manifestations. In the present study 18 new coumarin derivatives (CDs) were synthesized and characterized for antibiofilm activity against two model bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. It was observed that all the CDs executed significant effect in moderating activities against both planktonic and biofilm forms of these selected bacteria. Hence, to interpret the underlying probable reason of such antibiofilm effect, in-silico binding study of CDs with biofilm and motility associated proteins of these organisms were performed. All CDs have shown their propensity for occupying the native substrate binding pocket of each protein with moderate to strong binding affinities. One of the CDs such as CAMN1 showed highest binding affinity with these proteins. Interestingly, the findings of in-silico studies coincides the experimental results of antibiofilm and motility affect of CDs against both S. aureus and P. aeruginosa. Moreover, in-silico studies suggested that the antibiofilm activity of test CDs may be due to the interference of biofilm and motility associated proteins of the selected model organisms (PilT from P. aeruginosa and TarK, TarO from S. aureus). The detailed synthesis, characterization, methodology and results of biological screening along with computational studies have been reported. This study could be of greater interest in the context of the development of new anti-bacterial agent in the future.