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• 22105-09-5 4‐hydroxycoumarin 

Relevant academic research and scientific papers

Simple protic ionic liquid [Et3NH][HSO4] as a proficient catalyst for facile synthesis of biscoumarins

Abstract: We have explored a number of protic ionic liquids (PILs) as a catalyst for the synthesis of biscoumarins by condensation of 4-hydroxycoumarin with an aromatic aldehyde. Methylimidazolium- and triethylammonium-based PILs were synthesized by simple neutralization reaction with protic acids. Triethylammonium hydrogen sulfate [Et3NH][HSO4] was found to be the best among the studied PILs concerning the yield of products and reaction time period. Different biscoumarin derivatives were synthesized based on 4-hydroxycoumarin and various substituted aromatic aldehydes at optimum reaction conditions. Obtained products were separated just by simple filtration. The facile method does not require additional purification for formed products. The catalyst has shown better yields along with outstanding recyclability, providing an environmental benign protocol for the synthesis of biscoumarin derivatives. Graphical Abstract: Screening of simple protic ionic liquids as a catalyst in the synthesis of biscoumarins, out of which [Et3NH][HSO4] was found to be best among the studied PILs.

Coumarin-based inhibitors of HIV integrase

The structures of a large number of HIV-1 integrase inhibitors have in common two aryl units separated by a central linker. Frequently at least one of these aryl moieties must contain 1,2-dihydroxy substituents in order to exhibit high inhibitory potency. The ability of o-dihydroxy-containing species to undergo in situ oxidation to reactive quinones presents a potential limitation to the utility of such compounds. The recent report of tetrameric 4-hydroxycoumarin-derived inhibitor 5 provided a lead example of an inhibitor which does not contain the catechol moiety. Compound 5 represents a large, highly complex yet symmetrical molecule. It was the purpose of the present study to determine the critical components of 5 and if possible to simplify its structure while maintaining potency. In the present study, dissection of tetrameric 5 (IC50 = 1.5 μM) into its constituent parts showed that the minimum active pharmacophore consisted of a coumarin dimer containing an aryl substituent on the central linker methylene. However, in the simplest case in which the central linker aryl unit consisted of a phenyl ring (compound 8, IC50 = 43 μM), a significant reduction in potency resulted by removing two of the original four coumarin units. Replacement of this central phenyl ring by more extended aromatic systems having higher lipophilicity improved potency, as did the addition of 7- hydroxy substituents to the coumarin rings. Combining these latter two modifications resulted in compounds such as 3,3'-(2- naphthalenomethylene)bis[4,7-dihydroxycoumarin] (34, IC50 = 4.2 μM) which exhibited nearly the full potency of the parent tetramer 5 yet were structurally much simpler.

Efficient one-pot synthesis of 4-hydroxy-2h chromene by heterogeneously catalyzed zno np and mesoporous aluminosilicate catalysts in solvent free condition

4-Hydroxy-2H chromenes are fused benzopyran rings, an important class of biologically active compounds that are widely used as antibacterial, antiviral, antitumor, and anticancer agents. In this paper, we report the synthesis of 4-hydroxy-2H chromenes usi

The immobilized Ni(II) species on thiourea functionalized copper ferrite: a reusable nanocatalyst for synthesis of biscoumarins under solvent-free conditions

In this study, nanoparticles of CuFe2O4@SiO2@PTMS@Tu@Ni(II) as the reusable magnetic catalyst were prepared. Synthesis of the Ni(II)–CuFe2O4 system was carried out through a five-step procedure includ

Fabrication and characterization of the immobilized Cu(II) and Ni(II) species on silica-coated copper ferrite: as novel magnetically reusable nanocatalysts toward synthesis of biscoumarins

In this study, we have synthesized magnetically nanoparticles (MNPs) of CuFe2O4@SiO2@AAPTMS@Ni(II) and CuFe2O4@SiO2@AAPTMS@Cu(II). The prepared nanocomposite systems were characterized usin

Bis-coumarins; non-cytotoxic selective urease inhibitors and antiglycation agents

The current study is concerned with the identification of lead molecules based on the bis-coumarin scaffold having selective urease inhibitory and antiglycation activities. For that purpose, bis-coumarins (1-44) were synthesized and structurally characterized by different spectroscopic techniques. Eight derivatives 4, 8-10, 14, 17, 34, and 40 demonstrated urease inhibition in the range of IC50 = 4.4 ± 0.21–115.6 ± 2.13 μM, as compared to standard thiourea (IC50 = 21.3 ± 1.3 μM). Especially, compound 17 (IC50 = 4.4 ± 0.21 μM) was found to be five-fold more potent than the standard. Kinetic studies were also performed on compound 17 in order to identify the mechanism of inhibition. Kinetic studies revealed that compound 17 is a competitive inhibitor. Antiglycation activity was evaluated using glycation of bovine serum albumin by methylglyoxal in vitro. Compounds 2, 11-13, 16, 17, 19–22, 35, 37, and 42 showed good to moderate antiglycation activities with IC50 values of 333.63–919.72 μM, as compared to the standard rutin (IC50 = 294.46 ± 1.5 μM). Results of both assays showed that the compounds with urease inhibitory activity did not show any antiglycation potential, and vice versa. Only compound 17 showed dual inhibition potential. All compounds were also evaluated for cytotoxicity. Compounds 17, 19, and 37 showed a weak toxicity towards 3 T3 mouse fibroblast cell line. All other compounds were found to be non-cytotoxic. Urease inhibition is an approach to treat infections caused by ureolytic bacteria whereas inhibition of glycation of proteins is a strategy to avoid late diabetic complications. Therefore, these compounds may serve as leads for further research.

Synthesis and characterization of a magnetic graphene oxide/Zn-Ni-Fe layered double hydroxide nanocomposite: An efficient mesoporous catalyst for the green preparation of biscoumarins

In this study, a nanocomposite of Fe3O4@GO@Zn-Ni-Fe-layered double hydroxide was synthesized as a novel and efficient mesoporous magnetic nanocatalyst. The synthesis was carried out via the immobilization of Fe3O4/su

Dicoumarol derivatives: Green synthesis and molecular modelling studies of their anti-LOX activity

Dicoumarol derivatives were synthesized in the InCl3 catalyzed pseudo three-component reactions of 4-hydroxycoumarin with aromatic aldehydes in excellent yields. The reactions were performed in water under microwave irradiation. All synthesized

Evaluation of Antibacterial Activities of 4-Hydroxycoumarin Derivatives

Three kinds of 4-hydroxycoumarin derivatives, namely, biscoumarins (1-4), epoxydicoumarins (5-8) and dihydropyrans (9-12), were synthesized and the antibacterial activity of each of them was evaluated. The result of preliminary bioassay shows that the low

Choline Hydroxide: An Efficient and Biocompatible Basic Catalyst for the Synthesis of Biscoumarins Under Mild Conditions

In this work, choline hydroxide is found to be an efficient and green catalyst for the synthesis of biscoumarins through the Domino Knoevenagel-Michael reaction of a series of aldehydes with 4-hydroxylcoumarin under mild conditions. A series of aldehydes with different substituted functional groups, especially those which are sensitive to acid, have been converted to biscoumarins with good to excellent isolated yields, and the reactions can be easily scaled up to multigrams. The target products can be simply separated by filtration, and the aqueous solution of choline hydroxide (as filtrate) can then be reused for the next run reaction.