The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Ilia Manolov - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the antioxidant properties of some new 4-Hydroxycoumarin derivatives
European Journal of Medicinal Chemistry, 2008Co-Authors: Stancho Stanchev, Vera Hadjimitova, T. Traykov, T. Boyanov, Ilia ManolovAbstract:Abstract The aim of this investigation was to measure the activity of four 4-Hydroxycoumarin derivatives – three of them were described before and one was newly synthesized. The substances were ethyl 2-[(4-hydroxy-2-oxo-2 H -chromen-3-yl)(4-hydroxyphenyl)methyl]-3-oxobutanoate ( SS-14 ), 4-[1-(4-hydroxy-2-oxo-2 H -chromen-3-yl)-2-(ethoxycarbonyl)-3-oxobutyl]benzoic acid ( SS-17 ), ethyl 2-[(4-hydroxy-2-oxo-2 H -chromen-3-yl)(3-nitrophenyl)methyl]-3-oxobutanoate ( SS-21 ) and ethyl 2-[(3,4,5-trimethoxyphenyl)(4-hydroxy-2-oxo-2 H -chromen-3-yl)methyl]-3-oxobutanoate ( T-2 ). The synthesis of T-2 consists of two steps. First step was Knoevenagel reaction between 3,4,5-trimethoxybenzaldehyde and ethylacetoacetate. Ethyl 2-(3,4,5-trimethoxy)-phenylmethyleneacetoacetate was the product. Second step was Michael addition reaction between the latter product and 4-Hydroxycoumarin. All the compounds were tested in vitro for antioxidant activity in hypochlorous system. The assay was based on the luminol-dependent chemiluminescence of free radicals, which decreased in the presence of 4-Hydroxycoumarin derivative. Compound SS-14 (ethyl 2-[(4-hydroxy-2-oxo-2 H -chromen-3-yl)(4-hydroxyphenyl)methyl]-3-oxobutanoate) expresses the best scavenger activity at the highest concentration (10 −4 mol/L).
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synthesis computational study and cytotoxic activity of new 4 Hydroxycoumarin derivatives
European Journal of Medicinal Chemistry, 2008Co-Authors: Stancho Stanchev, Georgi Momekov, Frank Jensen, Ilia ManolovAbstract:Abstract Six new 4-Hydroxycoumarin derivatives have been synthesized. They were characterized by UV–vis, IR, 1 H NMR, 13 C NMR, mass spectral data, elemental analysis, TLC and melting point determination. The new 4-Hydroxycoumarin derivatives are studied by computational methods – DFT (B3LYP) and force field methods (MM2 and OPLS), in order to optimize their geometry and calculate quantum-chemical properties and conformational analysis. Five new 4-Hydroxycoumarin derivatives were tested for cytotoxic activity in two tumor cell lines – HL-60 and EJ. The obtained results are compared with the utilized anticancer drug melphalan. Two of these compounds – ethyl 2-[(3,4-dihydroxyphenyl)(4-hydroxy-2-oxo-2 H -chromen-3-yl)methyl]-3-oxobutanoate ( SS - 16 ) and ethyl 2-[(4-hydroxy-2-oxo-2 H -chromen-3-yl)(3-nitrophenyl)methyl]-3-oxobutanoate ( SS - 21 ) show comparatively good cytotoxic properties. Their activity is weaker than melphalan. SS - 16 seems to be more active than SS - 21 .
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Synthesis, Structure and Acid-Base Behaviour of Some 4-Hydroxycoumarin Derivatives
Zeitschrift für Naturforschung B, 2007Co-Authors: Stancho Stanchev, Cäcilia Maichle-mössmer, Ilia ManolovAbstract:The compound 3,3′-[(4-hydroxy-3-methoxy-5-nitrophenyl)methylene]-bis(4-hydroxy-2H-1benzopyran-2-one) (1) crystallizes in the monoclinic system, space group P21/n, with cell constants a = 16.859(4), b = 6.1624(15), c = 25.164(4) A, β = 98.019(19)◦ . The two 4-Hydroxycoumarin fragments are intramolecularly hydrogen-bonded between hydroxyl and carbonyl groups. The pHdependent color changes of 4-Hydroxycoumarin derivatives were studied by means of potentiometric and spectrophotometric titration. On the basis of the results obtained, the use of 3,3′-[(4-hydroxy-3methoxy-5-nitrophenyl)methylene]-bis(4-hydroxy-2H-1-benzopyran-2-one) as an indicator in alkalimetry and acidimetry is proposed.
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synthesis structure toxicological and pharmacological investigations of 4 Hydroxycoumarin derivatives
European Journal of Medicinal Chemistry, 2006Co-Authors: Ilia Manolov, Caecilia Maichlemoessmer, N D DanchevAbstract:Twenty 4-Hydroxycoumarin derivatives were synthesized. Five of them are described for the first time. The X-ray crystal structure analysis of 3,3'-(2,3,4-trimethoxyphenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (7) and 3,3'-(3,5-dimethoxy-4-hydroxyphenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (9) confirmed the structure of these compounds. A comparative pharmacological study of the anticoagulant effect with respect to Warfarin showed that the synthesized compounds have different anticoagulant activities. The most prospective compound is 3,3'-(4-chlorophenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (12) with low toxicity, very good index of absorption and dose dependent anticoagulant activity.
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Theoretical study of the substituent effect on the intramolecular hydrogen bonds in di(4‐Hydroxycoumarin) derivatives
International Journal of Quantum Chemistry, 2005Co-Authors: Tzvetan Mihaylov, Ilia Manolov, Ivelina Georgieva, G Bauer, Irena Kostova, Natasha TrendafilovaAbstract:Geometry optimization of ortho-, meta-, and para-pyridyl-substituted di(4-Hydroxycoumarin) [di(4-HC)] was performed with the density functional theory (DFT) [B3LYP/6-31G(d)] method. Two asymmetrical intramolecular OH…O hydrogen bonds (HBs) stabilized the structures. The calculated single HB energies varied from −62.56 to −47.53 kJ mol−1 and pointed to a relative strong hydrogen bond in the systems studied. The 2- and 6-pyridyl substituents produced the largest geometrical changes in di(4-Hydroxycoumarin) fragment. The highest total HB energy was found for 2-pyridyl-substituted and the lowest one for 6-pyridyl-substituted di(4-Hydroxycoumarin). The HB energy variations were confirmed with rotational barrier method calculations. Both steric and electrostatic factors were found to be responsible for the HB asymmetry in the compounds studied. According to the molecular electrostatic potential (MEP) calculations the most preferred reactive site for electrophilic attack of pyridyl-substituted di(4-Hydroxycoumarin)s are the pyridine nitrogen and the carbonyl oxygens, followed by the hydroxyl oxygens. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Marc Lemaire - One of the best experts on this subject based on the ideXlab platform.
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field assessment of 4 Hydroxycoumarin as an attractant for anthropophilic anopheles spp vectors of malaria in madagascar
Scientific Reports, 2020Co-Authors: Tovo Mbolatiana Andrianjafy, Voahangy Vestalys Ramanandraibe, Elodie Toavina Andrianarijaona, Niry Hasinandrianina Ramarosandratana, Lala Harivelo Ravaomanarivo, Patrick Mavingui, Marc LemaireAbstract:Mosquito-borne diseases like malaria are a major public health problem in tropical countries, such as Madagascar. Female Anopheles mosquito vectors the human malaria parasites (Plasmodium spp.) and is important indicator in malaria surveillance activities. Among the various means of vector control in Madagascar, the use of attractants for mass trapping of target species could be an alternative to insecticides. The aim of this study is to evaluate whether 4-Hydroxycoumarin can be used as an attractant for anthropophilic Anopheles spp. vectors of malaria. For this, a field study was conducted using CDC light traps in the village of Ambohidray, Madagascar. 16 days of trapping was conducted and four replicates nights were performed for each product tested. 4-Hydroxycoumarin, octenol and two types of blend of these products were tested. The results showed that 4-Hydroxycoumarin (2 mg) have a significant attractive effect on Anopheles spp. and significant selectivity towards Anopheles gambiae s.l, and Anopheles mascarensis which are both significant malaria vectors in Madagascar. A synergy of 4-Hydroxycoumarin with octenol was found to attract these mosquito vectors. A significant decrease in vector populations was observed during this experiment. These results suggest that 4-Hydroxycoumarin could be useful for malaria surveillance and the control of vector populations.
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3 methylene 2 4 chromandione in situ trapping introducing molecular diversity on 4 Hydroxycoumarin
RSC Advances, 2016Co-Authors: Adrien Montagutromans, Marc Lemaire, Manon Boulven, Florence PopowyczAbstract:3-Methylene-2,4-chromandione trapped in a solid-state stable Mannich adduct, is released in solution. In the presence of different nucleophiles, this highly reactive intermediate allows the introduction of molecular diversity on C-3 position of 4-Hydroxycoumarin.
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efficient c 3 reductive alkylation of 4 Hydroxycoumarin by dehydrogenative oxidation of benzylic alcohols through ruthenium catalysis
ChemInform, 2014Co-Authors: Marc Lemaire, Adrien Montagutromans, Manon Boulven, F PopowyczAbstract:Only benzylic alcohols react with 4-Hydroxycoumarin in the presence of Wilkinson′s catalyst.
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efficient c 3 reductive alkylation of 4 Hydroxycoumarin by dehydrogenative oxidation of benzylic alcohols through ruthenium catalysis
New Journal of Chemistry, 2014Co-Authors: Marc Lemaire, Adrien Montagutromans, Manon Boulven, F PopowyczAbstract:A practical route to prepare 4-Hydroxycoumarin derivatives functionalized at the C-3 position is described through a catalytic coupling reaction between 4-Hydroxycoumarin and a series of substituted benzylic alcohols. The reaction is conducted in the presence of tris(triphenylphosphine)ruthenium(II) dichloride (5 mol%), KOH (0.2 eq.) in tertamyl alcohol under microwave irradiation at 140 °C for 2 hours.
Allan E Rettie - One of the best experts on this subject based on the ideXlab platform.
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pharmacogenomics of 4 Hydroxycoumarin anticoagulants
Drug Metabolism Reviews, 2008Co-Authors: Nicholas T Au, Allan E RettieAbstract:Oral anticoagulants of the 4-Hydroxycoumarin class, typified by warfarin, are used worldwide to treat thromboembolic disease. These drugs show the beneficial attributes of high efficacy and low cost, but patient management can be complicated by their narrow therapeutic index and wide inter-individual variability in dosing. Our understanding of the latter complication has improved significantly in recent years due to intense investigation of genetic factors influencing drug pharmacokinetics (CYP2C9) and pharmacodynamic response (VKORC1). In particular, the discovery of polymorphisms in the VKORC1 gene that strongly impact oral anticoagulant dose has heightened expectations that genetic testing for a relatively small cadre of warfarin-response genes might substantially enhance patient care in this area, especially during the initiation phase of therapy. However, enthusiasm for genotype-based dosing of oral anticoagulants must be balanced against the ready availability of both a simple phenotypic test (proth...
N D Danchev - One of the best experts on this subject based on the ideXlab platform.
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synthesis structure toxicological and pharmacological investigations of 4 Hydroxycoumarin derivatives
European Journal of Medicinal Chemistry, 2006Co-Authors: Ilia Manolov, Caecilia Maichlemoessmer, N D DanchevAbstract:Twenty 4-Hydroxycoumarin derivatives were synthesized. Five of them are described for the first time. The X-ray crystal structure analysis of 3,3'-(2,3,4-trimethoxyphenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (7) and 3,3'-(3,5-dimethoxy-4-hydroxyphenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (9) confirmed the structure of these compounds. A comparative pharmacological study of the anticoagulant effect with respect to Warfarin showed that the synthesized compounds have different anticoagulant activities. The most prospective compound is 3,3'-(4-chlorophenylmethylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) (12) with low toxicity, very good index of absorption and dose dependent anticoagulant activity.
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synthesis toxicological and pharmacological assessment of some 4 Hydroxycoumarin derivatives
European Journal of Medicinal Chemistry, 1995Co-Authors: Ilia Manolov, N D DanchevAbstract:Summary The synthesis of seven coumarin derivatives from 4-Hydroxycoumarin and different unsaturated ketones is described. The structures of the synthesized compounds were proved by IR, 1 H-NMR and mass-spectral data. Acute toxicity studies of the compounds were performed on mice by oral and intraperitoneal administration. A comparative pharmacological study of the in vivo anticoagulant effects of the derivatives with respect to Warfarin showed that the new compounds have different anticoagulant activities. 4-Acetoxy-3-[1-(4-nitrophenyl)-3-oxobutyl]-2 H -1-benzopyran-2-one 2 showed slight acute toxicity and a higher anticoagulant effect than Warfarin.
Adrien Montagutromans - One of the best experts on this subject based on the ideXlab platform.
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3 methylene 2 4 chromandione in situ trapping introducing molecular diversity on 4 Hydroxycoumarin
RSC Advances, 2016Co-Authors: Adrien Montagutromans, Marc Lemaire, Manon Boulven, Florence PopowyczAbstract:3-Methylene-2,4-chromandione trapped in a solid-state stable Mannich adduct, is released in solution. In the presence of different nucleophiles, this highly reactive intermediate allows the introduction of molecular diversity on C-3 position of 4-Hydroxycoumarin.
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efficient c 3 reductive alkylation of 4 Hydroxycoumarin by dehydrogenative oxidation of benzylic alcohols through ruthenium catalysis
ChemInform, 2014Co-Authors: Marc Lemaire, Adrien Montagutromans, Manon Boulven, F PopowyczAbstract:Only benzylic alcohols react with 4-Hydroxycoumarin in the presence of Wilkinson′s catalyst.
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efficient c 3 reductive alkylation of 4 Hydroxycoumarin by dehydrogenative oxidation of benzylic alcohols through ruthenium catalysis
New Journal of Chemistry, 2014Co-Authors: Marc Lemaire, Adrien Montagutromans, Manon Boulven, F PopowyczAbstract:A practical route to prepare 4-Hydroxycoumarin derivatives functionalized at the C-3 position is described through a catalytic coupling reaction between 4-Hydroxycoumarin and a series of substituted benzylic alcohols. The reaction is conducted in the presence of tris(triphenylphosphine)ruthenium(II) dichloride (5 mol%), KOH (0.2 eq.) in tertamyl alcohol under microwave irradiation at 140 °C for 2 hours.
