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Coumarin
Terms modified by Coumarin Selected AbstractsToxicology and risk assessment of coumarin: Focus on human dataMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2010Klaus Abraham Abstract Coumarin is a secondary phytochemical with hepatotoxic and carcinogenic properties. For the carcinogenic effect, a genotoxic mechanism was considered possible, but was discounted by the European Food Safety Authority in 2004 based on new evidence. This allowed the derivation of a tolerable daily intake (TDI) for the first time, and a value of 0.1,mg/kg body weight was arrived at based on animal hepatotoxicity data. However, clinical data on hepatotoxicity from patients treated with coumarin as medicinal drug is also available. This data revealed a subgroup of the human population being more susceptible for the hepatotoxic effect than the animal species investigated. The cause of the high susceptibility is currently unknown; possible mechanisms are discussed. Using the human data, a TDI of 0.1,mg/kg body weight was derived, confirming that of the European Food Safety Authority. Nutritional exposure may be considerably, and is mainly due to use of cassia cinnamon, which is a popular spice especially, used for cookies and sweet dishes. To estimate exposure to coumarin during the Christmas season in Germany, a telephone survey was performed with more than 1000 randomly selected persons. Heavy consumers of cassia cinnamon may reach a daily coumarin intake corresponding to the TDI. [source] FTIR Spectroscopic and Theoretical Study of the Photochemistry of Matrix-isolated CoumarinPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007Nihal Ku The infrared spectrum of monomeric unsubstituted coumarin (C9H6O2; 2H -1-benzopyran-2-one), isolated in solid argon at 10 K is presented and assigned. The UV-induced (, > 200 nm) unimolecular photochemistry of the matrix-isolated compound was studied experimentally. Three main photoreactions were observed: (a) decarboxylation of the compound and formation of benzocyclobutadiene and CO2, with the Dewar form of coumarin as intermediate; (b) isomerization of the compound, leading to production of a conjugated ketene; and (c) decarbonylation, leading to formation of CO and benzofuran complex. Further decomposition of benzofuran to produce ethynol is suggested. Photochannels (a) and (b) correspond to those previously observed for matrix-isolated ,- pyrone and its sulfur analogs (Phys. Chem. Chem. Phys. 2004, 6, 929; J. Phys. Chem. A 2006, 110, 6415), while route (c) is similar to the UV-induced photochemistry of coumarin in the gaseous phase (J. Phys. Chem. A 2000, 104, 1095). Interpretation of the experimental data is supported by extensive calculations performed at the B3LYP/6-311++G(d,p), MP2/6-31G(d,p) and MP2/6-311++G(d,p) levels. [source] The Complex of Apomyoglobin with the Fluorescent Dye Coumarin 153,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2004P. K. Chowdhury ABSTRACT Understanding a protein's dielectric response requires both a theoretical model and a well-defined experimental system. The former has already been proposed by Song (J. Chem. Phys. 116, 9359 [2002]). We suggest that the latter is provided by the complex of coumarin 153 (C153) with apomyoglobin (ApoMb). C153 has been exhaustively studied and has proven to be an excellent probe of the solvation dynamics of polar solvents. Myoglobin is one of the most thoroughly studied proteins. Myoglobins from a wide range of species have been subject to X-ray structural analysis and site-directed mutagenesis. Here, we demonstrate the existence of a robust C153-apomyglobin system by means of molecular dynamics simulations, equilibrium binding studies using a Job's plot and capillary electrophoresis, circular dichroism and time-resolved fluorescence. The reorganization energy of C153 bound to ApoMb is compared with that of C153 in bulk solvent using the method of Jordanides et al. (J. Phys. Chem. B 103, 7995 [1999]). [source] Through-Bond Energy Transfer Cassettes with Minimal Spectral Overlap between the Donor Emission and Acceptor Absorption: Coumarin,Rhodamine Dyads with Large Pseudo-Stokes Shifts and Emission Shifts,ANGEWANDTE CHEMIE, Issue 2 2010Weiying Lin Prof. Eine neue Klasse von Cumarin-Rhodamin-Systemen, die auf dem Energietransfer über Bindungen (TBET) beruhen und minimale Überlappung zwischen Donoremission und Akzeptorabsorption aufweisen, zeichnet sich durch große Pseudo-Stokes-Verschiebungen (bis 230,nm) und Emissionsverschiebungen (bis 170,nm) aus. Die Nützlichkeit dieser TBET-Plattform für die Entwicklung von TBET-Sonden wurde mit einer neuen ratiometrischen pH-Fluoreszenzsonde demonstriert. [source] High-performance liquid chromatography determination of nitrated polycyclic aromatic hydrocarbons by indirect fluorescence detectionBIOMEDICAL CHROMATOGRAPHY, Issue 2 2009Salma M. Al-Kindy Abstract A high-performance liquid chromatography (HPLC) method for the analysis of nitrated polcyclic aromatic hydrocarbons (NPAHs) is reported. NPAH mixtures were pre-concentrated using solid-phase extraction and well resolved on a C18 column. They were detected using an indirect method involving the quenching of the emission from the fluorophores 5,6,7,8-tetrahydronaphthol (5,6,7,8-THN-1-OH), 7-amino-4-methyl coumarin (Coumarin 120, COU-120) and 3-hydroxy-4-(2-hydroxy-4-sulfo-1-naphthylazo)2-naphthalene carboxylic acid (Calcon carboxylic acid, CCA). Linear calibration curves were obtained in the range 1.1 × 10,9 to 1.1 × 10,8 mol/L. Using COU 120 as the fluorophore, the detection limit was 2.9 × 10,10 mol/L for 1-nitronaphthalene and 2.1 × 10,11 mol/L for 2-nitrofluorene. Recoveries of NPAHs from spiked tap water samples were between 88 and 100%. Copyright © 2008 John Wiley & Sons, Ltd. [source] ChemInform Abstract: Facile Synthesis of Coumarinyl Isothiocyanate from Amino Coumarin.CHEMINFORM, Issue 25 2010Sagar A. Mayekar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Iridium Catalyzed Alkylation of 4-Hydroxy Coumarin, 4-Hydroxy-2-quinolones and Quinolin-4(1H)-one with Alcohols under Solvent-Free Thermal Conditions.CHEMINFORM, Issue 3 2010Ronald Grigg Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis and Biological Evaluation of Novel Conjugated Coumarin -Thiazole Systems.CHEMINFORM, Issue 41 2009Franco Chimenti Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Short Route to [1,2,3]-Triazolyl Coumarin and Quinolone Derivatives by Cu(I) Catalyzed 1,3-Dipolar Cycloaddition and Fluorescence Studies.CHEMINFORM, Issue 24 2009Krishna C. Majumdar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of Carbamate Derivatives of Coumarin and Chromene.CHEMINFORM, Issue 9 2009A. V. Velikorodov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: tert-Amino Effect at a Coumarin and a 2-Quinolone System: Synthesis of 1,2-Fused 5H-Chromeno[4,3-b]pyridin-5-ones and a 6H-Benzo[h][1,6]naphthyridin-5-one.CHEMINFORM, Issue 19 2008Ivo C. Ivanov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Highly Effective Regioselective Method for the Synthesis of Substituted Coumarin- and Quinolone-Annulated Heterocycles Using a Palladium(0)-Catalyzed Reaction.CHEMINFORM, Issue 41 2007K. C. Majumdar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] BACE-1 Inhibitory Activities of New Substituted Phenyl-Piperazine Coupled to Various Heterocycles: Chromene, Coumarin and Quinoline.CHEMINFORM, Issue 27 2006Cedrik Garino Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of Imidazole, Coumarin and Isoxazole Containing New Triheterocyclic Compounds and Their Derivatives.CHEMINFORM, Issue 28 2005E. Rajanarendar No abstract is available for this article. [source] Syntheses of Diazadithiacrown Ethers Containing Appended Coumarin or 1-Aminonaphthalene Sidearms.CHEMINFORM, Issue 44 2003Hua-Can Song No abstract is available for this article. [source] Reactions of Lithium and Magnesium Derivatives of Substituted o- and m-Carboranes with 3-Ethoxycoumarin and Coumarin.CHEMINFORM, Issue 27 2003A. V. Kazantsev No abstract is available for this article. [source] Lunamarin C, a New Terpenoid Coumarin from Clausena heptaphyllaCHEMINFORM, Issue 50 2002Md. H. Sohrab Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Micellar Multitasking Device: Sensing pH Windows and Gauging the Lipophilicity of Drugs with Fluorescent SignalsCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2010Franck Denat Prof. Abstract A multitasking fluorescent device can be obtained by forming micelles of Triton,X-100, containing a lipophilic macrocyclic Cu2+ complex and the coordinating fluorophore Coumarin,343 (C343), which features a COOH moiety. At low pH the two micellised components do not interact, and the fluorescence of Courmarin,343 (C343) is intense. At intermediate pH, C343 is deprotonated and coordinates to the Cu2+ centre in its apical position, with fluorescence quenching. At higher pH the deprotonated C343 is displaced from Cu2+ by the formation of an OH, complex, and the fluorescence is revived. This allows the system to carry out its first task as it behaves as an "on,off,on" fluorescent sensor for pH windows. The "off" part of the window ranges from pH,6 to 8. In this interval, in which the carboxylate form of C343 is apically coordinated to the Cu2+ complex inside micelles, the device carries out its second task, that is, it behaves as a gauge for lipophilicity. For pHs between 6 and 8, molecules containing a COOH group are in their COO, form and distribute between bulk water and micelles proportionally to their lipophilicity. Upon entering the micelle, their COO, moiety competes for coordination with C343, displacing it from the Cu2+ centre, and this results in fluorescence revival, the intensity of which is also proportional to the lipophilicity of the examined molecule. We have chosen the physiological pH value (7.4) as the working pH, and we have examined the lipophilicity of fatty acids and of the widely used family of non-steroidal anti-inflammatory drugs (NSAIDs). The device successfully measures their lipophilicity, expressing it with an "off,on" type fluorescent signal, as demonstrated by the correlation of the fluorescence increase with the logarithmic water/octanol partition coefficient (log,P) and with the difference between the pKa observed in micelles and that measured in water for NSAIDs. [source] Sensitization to 26 fragrances to be labelled according to current European regulationCONTACT DERMATITIS, Issue 1 2007Results of the IVDK, review of the literature To study the frequency of sensitization to 26 fragrances to be labelled according to current European regulation. During 4 periods of 6 months, from 1 January 2003 to 31 December 2004, 26 fragrances were patch tested additionally to the standard series in a total of 21 325 patients; the number of patients tested with each of the fragrances ranged from 1658 to 4238. Hydroxymethylpentylcyclohexene carboxaldehyde (HMPCC) was tested throughout all periods. The following frequencies of sensitization (rates in %, standardized for sex and age) were observed: tree moss (2.4%), HMPCC (2.3), oak moss (2.0), hydroxycitronellal (1.3), isoeugenol (1.1), cinnamic aldehyde (1.0), farnesol (0.9), cinnamic alcohol (0.6), citral (0.6), citronellol (0.5), geraniol (0.4), eugenol (0.4), coumarin (0.4), lilial (0.3), amyl-cinnamic alcohol (0.3), benzyl cinnamate (0.3), benzyl alcohol (0.3), linalool (0.2), methylheptin carbonate (0.2), amyl-cinnamic aldehyde (0.1), hexyl-cinnamic aldehyde (0.1), limonene (0.1), benzyl salicylate (0.1), ,-methylionon (0.1), benzyl benzoate (0.0), anisyl alcohol (0.0). 1) Substances with higher sensitization frequencies were characterized by a considerable number of ,++/+++' reactions. 2) Substances with low sensitization frequencies were characterized by a high number of doubtful/irritant and a low number of stronger (++/+++) reactions. 3) There are obviously fragrances among the 26 which are, with regard to contact allergy, of great, others of minor, and some of no importance at all. [source] FS06.7 The new fragrance mix II , test results of a multicentre European StudyCONTACT DERMATITIS, Issue 3 2004Peter Frosch A new fragrance mix (FM II) with 6 frequently used chemicals was evaluated in consecutive patients patch tested in 6 dermatological centres in Europe. 28% FM II contained 5% Lyral, 1% citral, 5% farnesol, 5% coumarin, 1% citronellol and 10% alpha-hexyl cinnamic aldehyde (AHCA); in 14% FM II the single constituents' concentrations was lowered to 50% and in 2.8% FM II to 10%. Each patient was classified regarding a history of adverse reactions to fragrances: certain, probable, questionable and none. The frequency of positive reactions to the currently used 8% fragrance mix (FM I) and the new mix in 1703 patients was as follows: FM I, 6.6%; 2.8% FM II, 1.3%; 14% FM II, 2.9%; 28% FM II, 4.1%. The number of doubtful/irritant reactions was 7.2% for FM I and ranged from 1.8% to 10.6% for FM II. 8.7% of tested patients had a certain fragrance history. Of these 25.2% were positive to FM I, reactivity to FM II was dose-dependent and ranged from 8.1% to 17.6% in this subgroup. Comparing 2 groups of history , certain and none , values for sensitivity (sens) and specificity (spec) were calculated. Sens: FM I, 27.2%; 2.8% FM II, 8.7%; 14% FM II, 15.9%; 28% FM II, 21.5%. Spec: FM I, 96.3%; 2.8% FM II, 99.5%; 14% FM II, 98.7%; 28% FM II, 97.9%. 31/70 (44.3%) patients positive to 28% FM II were negative to FM I. In the group of patients with a certain history a total of 6 patients was found reacting only to FM II. Simultaneous break-down testing with the single constituents produced positive reactions in 54.3% for 28% FM II and 48% for 14% FM II. Lyral was the dominating single constituent with positive reactions (37.1% for 28% FM II, 36% for 14% FM II), followed by citral, farnesol, citronellol, AHCA and coumarin. Chemical analysis for the 6 constituents of FM II was performed on 25 products used by 12 patients being patch test positive to FM II. Lyral was detected in 76% of these products, citral in 16% and AHCA in 8%. In conclusion, the new FM II detects additional patients with contact allergy to fragrances missed by the currently used FM I. The medium concentration, 14% FM II, is probably the most useful one for diagnostic screening. [source] Contact sensitization from Compositae-containing herbal remedies and cosmeticsCONTACT DERMATITIS, Issue 4 2002Evy Paulsen The Compositae (Asteraceae) family of plants is currently an important cause of allergic plant contact dermatitis in Europe. The family comprises some of the oldest and most valued medicinal plants, and the increasing popularity of herbal medicine and cosmetics may theoretically result in a growing number of Compositae sensitizations from these sources. According to the literature at least 15 species, including among others arnica (Arnica montana), German and Roman chamomile (Chamomilla recutita and Chamaemelum nobile), marigold (Calendula officinalis), Echinacea and elecampane (Inula helenium), have been suspected of sensitization or elicitation of Compositae dermatitis. Epidemiological data are available for 2 species only, arnica and German chamomile, the rest of the evidence being anecdotal. Based on this, sensitization seems to occur relatively frequently with a few species such as arnica and elecampane, and occurs rarely with the majority, especially the widely used German chamomile. Sesquiterpene lactones are the most important allergens, but there are a few cases of sensitization from a coumarin, a sesquiterpene alcohol and a thiophene. The risk of elicitation of dermatitis by using Compositae-containing products in Compositae-sensitive individuals is by-and-large unknown. [source] Correction of a Reported Xanthone Synthesis: The Preparation of a Benzo[c]coumarinHELVETICA CHIMICA ACTA, Issue 3 2010Michael Abstract Reinvestigation of a reported synthesis of 5,8-dihydroxy-1,3-dimethoxyxanthone from the reaction of 3,5-dimethoxyphenol with 2-(methoxycarbonyl)-1,4-benzoquinone resulted in the identification of the product as the isomer of benzo[c]coumarin, i.e., 7,10-dihydroxy-1,3-dimethoxy-6H -dibenzo[b,d]pyran-6-one, established by X-ray crystallography. This requires the revision of the structures of the derivatives that were reported. [source] Four New 1,4-Benzoquinone Derivatives and One New Coumarin Isolated from Ardisia gigantifoliaHELVETICA CHIMICA ACTA, Issue 2 2010Hongwei Liu Abstract Four new 1,4-benzoquinone derivatives, belamcandaquinones J (1), K (2), L (3), and M (4), and one new coumarin, 5, were isolated from the rhizome of Ardisia gigantifolia. Their structures were established by means of spectroscopic methods, and their cytotoxicity was tested in vitro against the cell lines PC-3, EMT6, A549, Hela, RM-1, and SGC7901. In comparison with cisplatin, compound 5 showed strong cytotoxicity with an IC50 value of <30,,M against the cell lines PC-3 and A549. Compounds 1,4 showed no cytotoxicity against all cell lines. [source] Reversible Cluster Formation of Colloidal Nanospheres by Interparticle Photodimerization,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2004X. Yuan Abstract Crosslinked spherical nanoparticles based on trimethoxysilane monomers have been prepared by polycondensation in aqueous emulsion. These particles have been labeled chemically at their surface region with two different types of organic dye molecules (cinnamate, coumarin), which both are well known for their ability to undergo a reversible photodimerization if irradiated with light of a suitable wavelength. Upon irradiation of dilute solutions of these nanoparticles with UV light, the photodimerization of labels belonging to different colloidal nanoparticles caused the formation of large colloidal clusters consisting of chemically bound individual nanospheres. This process has been quantitatively investigated using light scattering and atomic force microscopy. Importantly, utilizing the reversibility of the photoreaction, the clusters could be broken up by irradiation of the sample with UV light of shorter wavelengths than the light used for their formation [source] Computational study of titanium (IV) complexes with organic chromophoresINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2006Ivan Kondov Abstract A computational study of small titanium complexes with the chromophores catechol, alizarin, and coumarin 343 is presented. Employing density functional theory (DFT), the ground-state geometries, energies, and harmonic frequencies of the different compounds are calculated. Furthermore, time-dependent DFT and the configuration interaction singles (CIS) method are used to determine excitation energies and excited-state gradients. Based on these results, the character of the excited states as well as electronic-vibrational coupling strengths are analyzed, and the implications for electron-transfer reactions at dye,semiconductor interfaces are discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] Coumarin A/AA induces apoptosis-like cell death in HeLa cells mediated by the release of apoptosis-inducing factorJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2009Carolina Álvarez-Delgado Abstract It has been demonstrated that naturally occurring coumarins have strong biological activity against many cancer cell lines. In this study, we assessed the cytotoxicity induced by the naturally isolated coumarin A/AA in different cancer cell lines (HeLa, Calo, SW480, and SW620) and in normal peripheral-blood mononuclear cells (PBMCs). Cytotoxicity was evaluated using the MTT assay. The results demonstrate that coumarin A/AA was cytotoxic in the four cancer cell lines tested and importantly was significantly less toxic in PBMCs isolated from healthy donors. The most sensitive cancer cell line to coumarin A/AA treatment was Hela. Thus, the programmed cell death (PCD) mechanism induced by this coumarin was further studied in this cell line. DNA fragmentation, histomorphology, cell cycle phases, and subcellular distribution of PCD proteins were assessed. The results demonstrated that DNA fragmentation, but not significant cell cycle disruptions, was part of the PCD activated by coumarin A/AA. Interestingly, it was found that apoptosis-inducing factor (AIF), a proapoptotic protein of the mitochondrial intermembrane space, was released to the cytoplasm in treated cells as detected by the western blot analysis in subcellular fractions. Nevertheless, the active form of caspase-3 was not detected. The overall results indicate that coumarin A/AA induces a caspase-independent apoptotic-like cell death program in HeLa cells, mediated by the early release of AIF and suggest that this compound may be helpful in clinical oncology. © 2009 Wiley Periodicals, Inc. J Biochem Mol Toxicol 23:263,272, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20288 [source] The Surgical Option in the Management of Acute Pulmonary EmbolismJOURNAL OF CARDIAC SURGERY, Issue 6 2008Justo Rafael Sádaba F.R.C.S. (C/Th) Traditionally this condition has been treated with thrombolysis or anticoagulation and support measures. Surgical embolectomy is carried out in situations of hemodynamic instability or contraindication for thrombolysis. We present our results of surgical embolectomy in patients with massive and submassive PE. Methods: Over a three-year period, we have carried out 20 surgical embolectomies for acute PE. The mean age was 66 years, and there were 11 males. In all cases, the diagnosis had been made by a computerized tomography (CT) pulmonary artery angiography. Nine patients (45%) arrived to the operating theater on inotropes, and two of them (10%) with ventilatory support. All patients underwent a median sternotomy, bicaval cannulation for institution of cardiopulmonary bypass (CPB), and main pulmonary arteriotomy for the removal of the thrombus. Results: The mean bypass time was 45 minutes. Two patients (12%) died after being unable to wean off CPB due to right heart failure. Among the 15 survivors, the median ventilation time in the intensive care unit was 24 hours. Twelve patients (60%) required inotropic support postoperatively for right heart failure. All but one survivor (94%) underwent an insertion of a permanent inferior vena cava filter and were anticoagulated with coumarin. The mean follow-up is 9.8 months and is 100% complete, with a survival of 94.5%. All patients were in the World Health Organization (WHO) functional class I, with no re-admissions for respiratory failure. Conclusion: In patients with acute massive or submassive PE, surgical embolectomy offers a valid therapeutic strategy. A right-sided heart failure is the main complication of this condition. [source] Synthesis of potentially photoactivatable coumarin derivatives via a 1,3-dipolar cycloadditionJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2008Elodie-Denise Chenot A copper (1)-catalyzed 1,3-dipolar cycloaddition reaction was used to prepare a series of mono and disubstituted 1,2,3-triazolyl-coumarins using a 1,3-cycloaddition ("Click Chemistry"). Starting coumarins were synthesized using classical or modified Pechmann's reaction. The propargyl group was introduced as either propargylether or as a propargylamide. Azides were prepared in a three steps procedure. Cycloaddition products, containing a coumarin and a photoactivatable moiety, were obtained in good yields. [source] tert -Amino effect at a coumarin and a 2-quinolone system: Synthesis of 1,2 fused 5H -chromeno[4,3- b]pyridin-5-ones and a 6H -benzo[h][1,6]naphthyridin-5-oneJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2008Ivo C. Ivanov Some novel 1,2-fused 5H -chromeno[4,3- b]pyridin-5-ones (5a,b) and a 6H -benzo[h][1,6]naphthyridin-5-one (5c) have been synthesized starting from the 4-chlorocoumarin-3-carbaldehyde (1a) or its N -methyl-2-quinolone analogue (1b) via subsequent Knoevenagel condensation and ring closure reaction known as the ,tert -amino effect'. These are rare examples of the tert -amino effect occurring at 2-pyrone and 2-pyridone ring. An unusual intramolecular redox reaction of the iminium ion 6, reported earlier, most probably follows analogous mechanism as the tert- amino effect reactions leading to 5. [source] Antinociceptive properties of coumarins, steroid and dihydrostyryl-2-pyrones from Polygala sabulosa (Polygalaceae) in miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2006Juliana V. Ardenghi We have investigated the possible antinociceptive action of the extract, fractions and pure compounds obtained from the whole plant Polygala sabulosa A. W. Bennett (Polygalaceae) in acetic acid-induced visceral pain in mice. Intraperitoneal injection of animals with the hydroalcoholic extract and fractions (CH2Cl2, EtOAc, n -BuOH, aqueous fraction) (1,100 mg kg,1) caused a dose-related and significant inhibition of the acetic acid-induced visceral nociceptive response. The CH2Cl2, EtOAc and n -BuOH fractions were more potent than the hydroalcoholic extract and aqueous fraction. The isolated compounds dihydrostyryl-2-pyrones (1, 2, 3), styryl-2-pyrone (7), ,-spinasterol (9), scopoletin (10) and two esters of the coumarin (scopoletin) obtained semisynthetically, acetylscopoletin (10a) and benzoylscopoletin (10b) (0.001,10 mg kg,1), exhibited significant and dose-related antinociceptive effects against acetic acid-induced visceral pain. The results distinguished, for the first time, the extract, fractions and pure compounds obtained from P. sabulosa that produced marked antinociception against the acetic acid-induced visceral nociceptive response, supporting the ethnomedical use of P. sabulosa. [source] | |||||||||||||||||||||||||||||||||||||