Coumarin compounds represent an important type of naturally occurring and synthetic oxygen-containing heterocycles with typical benzopyrone framework. This type of special benzopyrone structure enables its derivatives readily interact with a diversity of enzymes and receptors in organisms through weak bond interactions, thereby exhibit wide potentiality as medicinal drugs. So far, some coumarin-based drugs such as anticoagulant and antineurodegenerative agents have been extensively used in clinic. Coumarin-containing supramolecular medicinal agents as a new increasing expansion of supramolecular chemistry in pharmaceutical science have also been actively investigated in recent years. Coumarin-derived artificial ion receptors, fluorescent probes and biological stains are growing quickly and have a variety of potential applications in monitoring timely enzyme activity, complex biological events as well as accurate pharmacological and pharmacokinetic properties. This review provides a systematic summary and insight of the whole range of medicinal chemistry in the current developments of coumarin compounds as anticoagulant, antineurodegenerative, anticancer, antioxidative, antibacterial, antifungal, antiviral, antiparasitic, antiinflammatory and analgesic, antidiabetic, antidepressive and other bioactive agents as well as supramolecular medicinal drugs, diagnostic agents and pathologic probes, and biological stains. Some rational design strategies, structure-activity relationships and action mechanisms are discussed. The perspectives of the future development of coumarinbased medicinal chemistry are also presented.

Current Developments of Coumarin Compounds in Medicinal Chemistry

Coumarin heterocyclic derivatives: chemical synthesis and biological activity

Recent Advances in the Synthesis of Coumarin Derivatives via Knoevenagel Condensation: A Review

A simple, facile, and convenient practical method for the room temperature one-pot synthesis of a series of potentially biologically active coumarin-3-carboxylic acids has been developed in water from the Knoevenagel condensation and intramolecular cyclization of diverse 2-hydroxybenzaldehydes with Meldrum’s acid using either potassium carbonate or sodium azide as a commercially available, cheap, and eco-friendly catalyst. The salient features of the present protocol are mild reaction conditions, good to excellent yields, high atom-economy, environmentally benignity, easy isolation of products, without column chromatography, clean reaction profiles, and applicability toward large-scale synthesis.

Room Temperature One-Pot Green Synthesis of Coumarin-3-carboxylic Acids in Water: A Practical Method for the Large-Scale Synthesis

New coumaryl-thiazole derivatives with the acetamide moiety as a linker between the alkyl chains and/or the heterocycle nucleus were synthesized and in vitro tested as acetylcholinesterase (AChE) inhibitors. 2-(diethylamino)-N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)acetamide (6c, IC50 value of 43 nM) was the best AChE inhibitor with a selectivity index of 4151.16 over BuChE. Kinetic study of AChE inhibition revealed that 6c was a mixed-type inhibitor. Moreover, the result of H4IIE hepatoma cell toxicity assay for 6c showed negligible cell death. Molecular docking studies were also carried out to clarify the inhibition mode of the more active compounds. Best pose of compound 6c is positioned into the active site with the coumarin ring wedged between the residues of the CAS and catalytic triad of AChE. In addition, the coumarin ring is anchored into the gorge of the enzyme by H-bond with Tyr130.

Design, synthesis and docking study of novel coumarin ligands as potential selective acetylcholinesterase inhibitors

3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of 2-aminothiazole derivative 3
 via bromination of 1 followed by treatment of the formed acetylbromide 2 with thiourea or via Bignailli reaction of 1. Treatment of 3 with 2 afforded the bis-coumarin 4, whereas, cyanoacetylation of 3 followed by treatment of the formed cyanoacetamide 6 with salicyaldehyde give the bis-coumarin 7. Reaction of 6 with phenyl isothiocyanate in DMF/KOH produced the potassium salt 8, which cyclized with chloroacetyl chloride to give the thiazolidinone 9. Acidification of 8 with HCl afforded the thiocarbamoyl 10, which condensed with 2 in DMF to give the mercapto derivative 12, whereas in DMF/TEA gave the thiophene derivative 13. The thiophenes 15a–c were achieved via treatment of the thiocarbamoyls 14a–c with 2 in DMF/TEA, whereas, in DMF gave the corresponding thiazoles 16a–c. Treatment of the components 17a, b with carbon disulfide in DMF/KOH followed by addition of 2 afforded the dithioacetals 19a, b. Cyclization of 19b under alkaline condition gave the desired thiophene 20. Representative compounds of the synthesized products were evaluated as antitumor and antioxidant agents. 3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of different coumarin derivatives. Newly synthesized compounds were elucidated by analytical and spectral data. Representative compounds of the synthesized products were evaluated as antitumor and antioxidant agents.

Synthesis, antitumor and antioxidant evaluation of some new thiazole and thiophene derivatives incorporated coumarin moiety

3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of 2-aminothiazole derivative 3 via bromination of 1 to afford acetylbromide 2 followed by treatment with thiourea or via Biginelli reaction of 1. Treatment of 3 with 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, 2-methyl-4H-benzo[d][1,3]oxazin-4-one, furo[3,4-b]pyrazine-5,7-dione or 2-methyl-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d][1,3]oxazin-4-one afforded diazine derivatives 4-7. Also, pyridopyrimidine 8 was obtained via a one pot reaction of 6-aminothiouracil, p-chlorobenzaldehyde and 3-acetylcoumarin. Moreover, refluxing of 6-aminothiouracil with one equivalent amount of 2 afforded the thiazolopyrimidine 9, while the pyrrolothiazolopyrimidine 10 was revealed when two equivalent amounts of 2 was used. Furthermore, treatment of enamine 11 with 2-aminobenzothiazole or 6-aminothiouracil afforded the pyrimidine derivatives 12 and 13, respectively. Transamination of enamine 11 with m-anisidine followed by cyclization of the resulting enaminone 14 gave the desired quinoline 15. Also, treatment of 11 with thiophenol in dioxane gave the mercapto derivative 16. Moreover, coupling of 11 with 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl-diazonium chloride, followed by complete cyclization of the resulting product afforded the pyridopyrazolothiazine 19 via the intermediate 18. Furthermore, the pyrazolopyrimidine 20 was revealed via a one pot condensation of 11, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one and ammonium acetate. The thiadiazine derivatives 21-23 were obtained via treatment of 2 with the corresponding o-aminothiols. Desulphonation of 23 afforded the pyrazolotriazine 24. Finally, reaction of 2 with 2-hydroxybenzaldehyde gave benzofuran derivative 25. Representative compounds of the synthesized products were evaluated as antioxidant agents.

Synthesis and Antioxidant Evaluation of Some New 3‐Substituted Coumarins



Tetra-n-butylammonium fluoride (TBAF) is an organic compound with the formula C16H36FN. It can exist as anhydrous or hydrated (C16H42FNO3). It is soluble in water and THF and utilized as a base in the preparation of triple monoamine reuptake inhibitors, conjugated dienoic acid esters, and polyacetylenic glucosides. This review aims to summarize the chemistry of TBAF.


Tetra-n-Butyl Ammonium Fluoride (TBAF) as an Efficient
Catalyst

From the synthesized new title compounds the coumarins (VII), (XII), and (XVI) exhibit a high antioxidant activity in comparison to ascorbic acid.

Eman A. Baz

Papers

Synthesis, antitumor and antioxidant evaluation of some new thiazole and thiophene derivatives incorporated coumarin moiety

Synthesis and Antioxidant Evaluation of Some New 3‐Substituted Coumarins

Tetra-n-Butyl Ammonium Fluoride (TBAF) as an Efficient Catalyst

Synthesis and Antioxidant Evaluation of Some New 3‐Substituted Coumarins.