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Journal articles on the topic 'Hydroxycoumarins'

Author: Grafiati

Published: 4 June 2021

Last updated: 27 April 2022

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1

Bhuyan, Pulak, Sinki Kolita, Leema Dutta, and Pankaj Das. "One-Pot Synthesis of Unsymmetrical Bis(4-Hydroxycoumarin-3-yl)methanes." Synlett 28, no. 17 (July 13, 2017): 2291–94. http://dx.doi.org/10.1055/s-0036-1589065.

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Unsymmetrical bis(4-hydroxycoumarin-3-yl)methane derivatives have been synthesized from 4-hydroxycoumarins, aldehydes, and secondary amines via 3-(aminoalkyl)-4-hydroxycoumarin intermediates, followed by substitution.

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2

Traven, Valery F., Larisa I. Vorobjeva, Tatjana A. Chibisova, Edward Andrew Carberry, and Noelle Jean Beyer. "Electronic absorption spectra and structure of hydroxycoumarin derivatives and their ionized forms." Canadian Journal of Chemistry 75, no. 4 (April 1, 1997): 365–76. http://dx.doi.org/10.1139/v97-042.

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Electronic absorption spectra of 18 hydroxycoumarin derivatives and their ionized forms have been studied. Close agreement between experimental and the PPP CI calculated electron absorption band energies has been found in most cases. Strong polarization of the carbonyl function of the pyrone ring in the 7-hydroxycoumarin derivatives, H-bonding between the hydroxyl group and neighboring substituent in the ortho-substituted hydroxycoumarins, as well as their tautomeric transformations, have been suggested in the discussion of the electronic absorption spectra of the hydroxycoumarin derivatives. In accord also with calculational results, ionization of the hydroxyl function leads to a bathochromic shift of the longest-wavelength absorption bands in the spectra of 7-hydroxycoumarin derivatives. The ionization has no effect on the electronic absorption of the 4-hydroxycoumarin derivatives. Relative stabilities of the tautomeric forms of hydroxycoumarin derivatives and their ionized forms have also been compared by MNDO calculations. Keywords: hydroxycoumarins, intramolecular H-bonding, ionization, electronic absorption spectra, keto–enol tautomerism.

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3

Anary-Abbasinejad, Mohammad, Hossein Anaraki-Ardakani, Azimeh Saidipoor, and Mahmood Shojaee. "Synthesis of 3-[(acetylamino)(aryl)methyl]-4-Hydroxycoumarins." Journal of Chemical Research 2007, no. 9 (September 2007): 535–37. http://dx.doi.org/10.3184/030823407x247785.

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One-pot, three-component reaction between aryl aldehydes, 4-hydroxycoumarin, and acetonitrile in the presence of chlorosulfonic acid affords 3-[(acetylamino)(aryl)methyl]-4-hydroxycoumarins in excellent yields.

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4

Wu, Nan, Xinnian Li, Xin Xu, and Daqing Shi. "Synthesis of 3,3′-arylmethylidenebis-4-hydroxycoumarin derivatives catalysed by KF-montmorillonite." Journal of Chemical Research 2007, no. 10 (October 2007): 561–62. http://dx.doi.org/10.3184/030823407x255551a.

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3,3′-Arylmethylidenebis-4-hydroxycoumarins derivatives have been synthesised in good yields by the Michael addition reaction of aromatic aldehydes with 4-hydroxycoumarin in DMF catalysed by KF-montmorillonite.

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5

Anary-Abbasinejad, Mohammad, Khadijeh Charkhati, and Alireza Hassanabadi. "Stereoselective synthesis of 3-[2-(dialkoxyphosphoryl)-1,2-dialkoxycarbonyl-ethyl]-4-hydroxycoumarins by reaction between trialkyl phosphites, dialkyl acetylenedicarboxylates and 4-hydroxycoumarin." Journal of Chemical Research 2009, no. 5 (May 2009): 319–21. http://dx.doi.org/10.3184/030823409x450435.

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A three-component reaction between trialkyl phosphites, dialkyl acetylenedicarboxylates and 4-hydroxycoumarin is described as a simple and efficient route for the synthesis of 3-[2-(dialkoxyphosphoryl)-1,2-dialkoxycarbonyl-ethyl]-4-hydroxycoumarins in high yields.

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6

Yoon, Jeong A., and Young Taek Han. "Efficient Synthesis of Pyrido[3,2-c]coumarins via Silver Nitrate Catalyzed Cycloisomerization and Application to the First Synthesis of Polyneomarline C." Synthesis 51, no. 24 (September 30, 2019): 4611–18. http://dx.doi.org/10.1055/s-0037-1610730.

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Herein, we report an efficient method for the synthesis of the pyrido[3,2-c]coumarin scaffold, one of the privileged heterocycle-fused coumarin scaffolds, via a AgNO3-catalyzed cycloisomerization of 4-(propynylamino)coumarins obtained from diverse 4-hydroxycoumarins. This concise method affords pyrido[3,2-c]coumarin analogues bearing diverse substituents on the benzene or pyridine ring in moderate to good yields. Moreover, this methodology was extended to the facile synthesis of polyneomarline C, a natural pyrido[3,2-c]coumarin derivative isolated from the Chinese herbal medicine Polyalthia nemoralis A. DC., in three steps and in 26% overall yield from the known 4-hydroxycoumarin.

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7

Kostova, Ivanka. "Hydroxycoumarins fromFraxinus ornusBark." Planta Medica 58, no. 05 (October 1992): 484. http://dx.doi.org/10.1055/s-2006-961529.

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8

Timonen, Juri, Paula Aulaskari, Pipsa Hirva, and Pirjo Vainiotalo. "Negative Ion Electrospray Ionization Mass Spectrometry and Computational Studies on Substituted 7-Hydroxycoumarins." European Journal of Mass Spectrometry 15, no. 5 (October 2009): 595–603. http://dx.doi.org/10.1255/ejms.1019.

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Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization collision-induced dissociation (CID) mass spectrometry. Fragmentation pathways were also investigated by computation method using the B3LYP density functional theory. In general, the most important fragmentations of the 7-hydroxycoumarin [M – H]− ions were the elimination of CO2 and CO which agreed with the calculated energies of the proposed fragmentation reactions. In most cases, methyl group elimination was also favorable. Methyl group elimination occurred in three different ways, the most interesting being hydrogen rearrangement from a neighboring alkyl group to a ring carbon, which led to a benzyl radical formation. In some cases, CH2CO elimination was observed as well. Isomeric compounds gave rise to different CID spectra.

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9

Sizov, A. Yu, A. F. Kolomiets, and A. F. Fokin. "3-Polyfluoroalkylthio-4-hydroxycoumarins." Journal of Fluorine Chemistry 58, no. 2-3 (August 1992): 342. http://dx.doi.org/10.1016/s0022-1139(00)80807-6.

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10

Huitink, Geraldine M. "Studies of 7-hydroxycoumarins." Talanta 35, no. 12 (December 1988): 973–76. http://dx.doi.org/10.1016/0039-9140(88)80231-5.

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11

Ganguly, Nemai C., Sanjoy Dutta, Mrityunjoy Datta, and Prithwiraj De. "Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate." Journal of Chemical Research 2005, no. 11 (November 2005): 733–35. http://dx.doi.org/10.3184/030823405774909342.

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Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.

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12

Guo, Tao, and Xu-Ning Wei. "Ammonium Iodide-Mediated Sulfenylation of 4-Hydroxycoumarins or 4-Hydroxyquinolinones with a Sulfonyl Chloride as a Sulfur Source." Synlett 28, no. 18 (August 2, 2017): 2499–504. http://dx.doi.org/10.1055/s-0036-1589083.

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A novel ammonium iodide-induced sulfenylation of 4-hydroxycoumarins or 4-hydroxyquinolinones by using an aryl- or alkylsulfonyl chloride as the sulfur source gave a wide range of 3-sulfanyl-4-hydroxycoumarins or 3-sulfanyl-4-hydroxyquinolinones, respectively, in moderate to good yields. This method provides as a simple approach to the direct formation of C–S bonds, which is of high value and utility in the pharmaceutical industry.

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13

Bulut, M., and Ç. Erk. "Improved synthesis of some hydroxycoumarins." Dyes and Pigments 30, no. 2 (January 1996): 99–104. http://dx.doi.org/10.1016/0143-7208(95)00060-7.

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14

Komissarenko, A. N., and V. N. Kovalev. "Hydroxycoumarins and flavones ofSecurigera securidaca." Chemistry of Natural Compounds 23, no. 2 (1987): 252. http://dx.doi.org/10.1007/bf00598775.

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15

Abrams, Barny. "Mono-Chlorinated 3-Carboxy-7-Hydroxycoumarin: A Highly Fluorescent and Water-Soluble Violet Excitable Dye for Cell Analysis." Blood 112, no. 11 (November 16, 2008): 4929. http://dx.doi.org/10.1182/blood.v112.11.4929.4929.

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Abstract In our search for new violet excitable dyes with improved photochemical properties, we examined several halogen substituted 7-hydroxycoumarins and found that chlorinated derivatives could be as bright as their fluorinated analogs. In particular, mono-chlorinated 3-carboxy-7-hydroxycoumarin (V450) has a quantum yield equal to 3-carboxy-6,8- difluoro-7-hydroxycoumarin (Pacific Blue™). Antibodies specific to various cell surface markers (CD3, CD4, CD45) were labeled with V450 and tested in single color flow cytometry assays. Our results show that conjugates of V450 are brighter than the same clones labeled with Pacific Blue™. Additional studies were performed in which V450-antibody conjugates were included in 8-color cocktails, along with FITC, PE, PerCP-Cy5.5, PE-Cy7, APC, and APC-H7 conjugates, aimed at subsetting lymphocytes and myeloid cells. These cocktails met all standards of performance for the particular applications for which they were designed, including stability, lack of interaction between components, and brightness. The new V450 fluorochrome proved to be compatible with both FACSLyse and PharmLyse processing of EDTA anti-coagulated whole blood, and showed no signs of adverse effects on unfixed cells.

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16

Durand-Niconoff, J. Sergio, Erik Ortiz-Blanco, Gabriela Sosa-Ortiz, José L. Olivares-Romero, Enrique Juárez-Aguilar, Eva Luz Montoya-Hernández, Cynthia Fernández-Pomares, et al. "Mannich bases of hydroxycoumarins: synthesis, DFT/QTAIM computational study and assessment of biological activity." RSC Advances 11, no. 50 (2021): 31260–71. http://dx.doi.org/10.1039/d1ra04611j.

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17

Liu, Chang-Ling, Miao Li, Ai-Ying Guan, Hong Zhang, and Zheng-Ming Li. "Design, Synthesis and Fungicidal Activity of Novel (E)-Methyl 2-{2-[(coumarin-7-yloxy)methyl]phenyl}-3-methoxyacrylates." Natural Product Communications 2, no. 8 (August 2007): 1934578X0700200. http://dx.doi.org/10.1177/1934578x0700200811.

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A number of 7-hydroxycoumarins (5), on treatment with one equivalent of ( E)-methyl 2-{2-[(chloromethyl)phenyl]}-3-methoxyacrylate (6) at 80°C for 6–8 h, afforded ( E)-methyl 2-{2-[(coumarin-7-yloxy)methyl]phenyl}-3-methoxyacrylates (2) in 80–85% yields. The 7-hydroxycoumarins (5) were in turn prepared from resorcinols (3) and substituted ethyl 3-oxopropanoate (4). Subsequently, results of biological activities evaluated in the greenhouse indicated that several of these compounds have good fungicidal activity against cucumber downy mildew (CDM) at 25g ai/ha.

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18

Pham, Quyen T., Phong Q. Le, Ha V. Dang, Hiep Q. Ha, Huong T. D. Nguyen, Thanh Truong, and Tri Minh Le. "Iodine-mediated formal [3 + 2] annulation for synthesis of furocoumarin from oxime esters." RSC Advances 10, no. 72 (2020): 44332–38. http://dx.doi.org/10.1039/d0ra07566c.

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19

To, Tuong A., Yen H. Vo, Anh T. Nguyen, Anh N. Q. Phan, Thanh Truong, and Nam T. S. Phan. "A new route to substituted furocoumarins via copper-catalyzed cyclization between 4-hydroxycoumarins and ketoximes." Organic & Biomolecular Chemistry 16, no. 28 (2018): 5086–89. http://dx.doi.org/10.1039/c8ob01064a.

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20

Bondarenko, S. P., M. S. Frasinyuk, and V. P. Khilya. "Aminomethylation of 3-aryl-7-hydroxycoumarins." Chemistry of Heterocyclic Compounds 46, no. 5 (September 2010): 529–35. http://dx.doi.org/10.1007/s10593-010-0541-y.

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21

Shcherbakov, K. V., Ya V. Burgart, M. I. Kodess, and V. I. Saloutin. "Structure of 5,6,7,8-tetrafluoro-4-hydroxycoumarins." Chemistry of Heterocyclic Compounds 48, no. 9 (November 27, 2012): 1297–306. http://dx.doi.org/10.1007/s10593-012-1136-6.

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22

Serra, Silvia, Giulio Ferino, Maria João Matos, Saleta Vázquez-Rodríguez, Giovanna Delogu, Dolores Viña, Enzo Cadoni, Lourdes Santana, and Eugenio Uriarte. "Hydroxycoumarins as selective MAO-B inhibitors." Bioorganic & Medicinal Chemistry Letters 22, no. 1 (January 2012): 258–61. http://dx.doi.org/10.1016/j.bmcl.2011.11.020.

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23

Chen, Zi-cong, Lang Tong, Zhi-bo Du, Zhi-feng Mao, Xue-jing Zhang, Yong Zou, and Ming Yan. "Annulation of β-naphthols and 4-hydroxycoumarins with vinylsulfonium salts: synthesis of dihydrofuran derivatives." Organic & Biomolecular Chemistry 16, no. 15 (2018): 2634–38. http://dx.doi.org/10.1039/c8ob00293b.

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24

Rashid, Mohammad A., James A. Armstrong, Alexander I. Gray, and Peter G. Waterman. "Novel C-Geranyl 7-Hydroxycoumarins from the Aerial Parts of Eriostemon tomentellus." Zeitschrift für Naturforschung B 47, no. 2 (February 1, 1992): 284–87. http://dx.doi.org/10.1515/znb-1992-0221.

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From the aerial parts of Eriostemon tomentellus five coumarins have been isolated. These have been characterized as ostruthin (6-geranyl-7-hydroxycoumarin (1)) and the novel compounds, 8-geranyl-7-hydroxycoumarin (2), (E)-6-(7-hydroxy-3,7-dimethylocta-2,5-dienyl)- 7-hydroxycoumarin (3), (E)-6-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-7-hydroxycoumarin (4), and 6-(6-hydroxy-3,7-dimethylocta-2,7-dienyl)-7-hydroxycoumarin (5). In addition tembamide (2-{4-methoxyphenyl}-2-hydroxy-N-benzoylethylamine (6 ) was isolated and the l3C NMR spectrum reported for the first time.

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25

Zhang, Sheng-Ling, Zhi-Shu Huang, Lin-Kun An, Xian-Zhang Bu, Lin Ma, Yue-Ming Li, Albert S. C. Chan, and Lian-Quan Gu. "Synthesis of Zwitterionic 4-Hydroxycoumarin Derivatives through a Unique Reaction of 4-Hydroxycoumarins withp- Benzoquinone and Pyridine." Organic Letters 6, no. 26 (December 2004): 4853–55. http://dx.doi.org/10.1021/ol048109p.

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26

Zhou, Hui, Xinzhao Deng, Zhenjun Ma, Aihua Zhang, Qixue Qin, Ren Xiang Tan, and Shouyun Yu. "Synthesis of furo[3,2-c]coumarin derivatives using visible-light-promoted radical alkyne insertion with bromocoumarins." Organic & Biomolecular Chemistry 14, no. 25 (2016): 6065–70. http://dx.doi.org/10.1039/c6ob00768f.

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27

Balalas, T., G. Stratidis, D. Papatheodorou, E. E. Vlachou, C. Gabriel, D. Hadjipavlou-Litina, and K. Litinas. "One-pot Synthesis of 2-Substituted 4H-Chromeno[3,4-d]oxazol-4-ones from 4-Hydroxy-3-nitrocoumarin and Acids in the Presence of Triphenylphosphine and Phosphorus Pentoxide under Microwave Irradiation." SynOpen 02, no. 02 (April 2018): 0105–13. http://dx.doi.org/10.1055/s-0036-1591977.

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2-Substituted 4H-chromeno[3,4-d]oxazol-4-ones are prepared from 4-hydroxy-3-nitrocoumarin and acids by one-pot reaction in the presence of PPh3 and P2O5 under microwave irradiation or by one-pot two-step reactions in the presence of Pd/C and hydrogen and then P2O5 under microwave irradiation. The fused oxazolocoumarins were also synthesized from 3-amido-4-hydroxycoumarins and P2O5 under microwave irradiation. The 3-amido-4-hydroxycoumarins are obtained almost quantitatively from 4-hydroxy-3-nitrocoumarin, acids and PPh3 under microwave irradiation, or in the presence of Pd/C and H2 on heating. Preliminary biological tests indicate significant inhibition of soybean lipoxygenase and antilipid peroxidation for both oxazolocoumarins and o-hydroxyamidocoumarins.

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28

Kumaran, Subramani, Mohan Prabhakaran, Narayanan Mariyammal, and Kanniyappan Parthasarathy. "Catalyst-free 1,6-conjugate addition of indoles and 4-hydroxycoumarins to para-quinone methides: synthesis of unsymmetrical triarylmethanes." Organic & Biomolecular Chemistry 18, no. 39 (2020): 7837–41. http://dx.doi.org/10.1039/d0ob01789b.

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29

Hussain, Majid, Chuang Niu, and Guan-Wu Wang. "Palladium-catalyzed synthesis of [60]fullerene-fused furochromenones and further electrochemical functionalization." Organic Chemistry Frontiers 7, no. 10 (2020): 1249–54. http://dx.doi.org/10.1039/d0qo00264j.

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The palladium-catalyzed heteroannulation of [60]fullerene with 4-hydroxycoumarins affords [60]fullerene-fused furochromenones, which can be further derivatized via an electrochemical method to synthesize 1,2,3,4-adducts.

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30

Majumdar, K. C., A. Biswas, and P. P. Mukhopadhyay. "SnCl4I2 mediated regioselective 6-endo- and 5-exo-cyclization of ortho-allylenols." Canadian Journal of Chemistry 83, no. 12 (December 1, 2005): 2046–51. http://dx.doi.org/10.1139/v05-212.

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3-Allyl-4-hydroxycoumarins and 4-allyl-3-hydroxycoumarins are obtained in 90%92% yields by the thermal [3,3] sigmatropic rearrangement of the corresponding ethers. 3-Allyl-4-hydroxy-6-methylpyrone is obtained from the direct alkylation of 4-hydroxy-6-methylpyrone with allyl halide. These substrates on treatment with SnCl4I2 at 25 °C give a mixture of both 5-exo- and 6-endo-cyclization products. However, regioselective formation of 5-exo products is observed when the reactions are conducted at lower temperatures (05 °C, kinetically controlled), while the reaction at a higher temperature (50 °C, thermodynamically controlled) affords regioselectively 6-endo cyclization products.Key words: stannic chloride, iodine, claisen rearrangement, 6-endocyclization, 5-exocyclization, kinetically controlled reaction, thermodynamically controlled reaction.

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31

Kausar, Nazia, Partha Pratim Ghosh, Gargi Pal, and Asish R. Das. "Graphene oxide nanosheets: a highly efficient and reusable carbocatalyst catalyzes the Michael-cyclization reactions of 4-hydroxycoumarins, 4-hydroxypyrone and 4-hydroxy-1-methylquinolinone with chalcone derivatives in aqueous media." RSC Advances 5, no. 74 (2015): 60199–207. http://dx.doi.org/10.1039/c5ra08776g.

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Graphene oxide nanosheets: a highly efficient and reusable carbocatalyst catalyzes the Michael-cyclization reactions of 4-hydroxycoumarins, 4-hydroxypyrone and 4-hydroxy-1-methylquinolinone with chalcone derivatives in aqueous media.

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32

Li, Hui-Yin, and George A. Boswell. "A facile synthesis of fluorinated 4-hydroxycoumarins." Tetrahedron Letters 37, no. 10 (March 1996): 1551–54. http://dx.doi.org/10.1016/0040-4039(96)00101-3.

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33

Iossifova, Tania, Ivanka Kostova, and Ljuba N. Evstatieva. "Secoiridoids and hydroxycoumarins in Bulgarian Fraxinus species." Biochemical Systematics and Ecology 25, no. 3 (April 1997): 271–74. http://dx.doi.org/10.1016/s0305-1978(97)00006-9.

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34

Smith, Gerald J., Roderick J. Weston, Ying Tang, Yinrong Lu, and Jolon M. Dyer. "Photoproducts of 7-Hydroxycoumarins in Aqueous Solution." Australian Journal of Chemistry 65, no. 10 (2012): 1451. http://dx.doi.org/10.1071/ch12292.

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Near-UV irradiation of aqueous solutions of 7-hydroxy-6-methoxycoumarin (scopoletin) and 6,7-dihydroxycoumarin (esculetin) resulted in the formation of dimers. Substantially greater amounts of the 7-hydroxy-6-methoxycoumarin photodimer were produced compared with that of 6,7-dihydroxycoumarin. Fluorescence spectra indicated that the initial photolytic reaction involves the excited state of the phenolate form of the monomeric coumarin. The electro-spray ionization (ESI) mass spectrum suggested that the major product (with a sodiated quasimolecular ion at m/z 405) from the photolysis of scopoletin in water had formed by oxidative dimerisation and possibly had a 3,3′-bond. A second dimer (with a sodiated quasimolecular ion at m/z 407) was probably a 2 + 2 cyclodimer. This work concluded that photolysis of coumarins in water results in oxidative dimerisation whereas photolysis in the solid state or in organic solvents results in cyclodimerisation. Minor monomeric photoproducts were a dihydroxy-6-methoxycoumarin from 7-hydroxy-6-methoxycoumarin and a trihydroxycoumarin from 6,7-dihydroxycoumarin. During ESI-mass spectrometry (ESI-MS), sodiated quasimolecular ions of the photodimer formed more readily than protonated quasimolecular ions and the sodiated ions did not fragment readily. Protonated quasimolecular ions of the monomeric coumarins formed more readily than their sodiated counterparts and the protonated ions fragmented to create daughter ion spectra that were useful for chemical structural assignment.

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35

Duong, Truc-Vi H., Todd S. Carroll, Daniel S. Bejan, and Edward J. Valente. "β-Chain Hydrogen-Bonding in 4-Hydroxycoumarins." Journal of Chemical Crystallography 50, no. 4 (November 14, 2019): 387–99. http://dx.doi.org/10.1007/s10870-019-00813-5.

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36

Ghiami-Shomami, Ali, Mona Ashtari-Delivand, Bahram Ghalami-Choobar, and Ivo Leito. "Computational studies of acidities of some hydroxycoumarins." Computational and Theoretical Chemistry 1190 (November 2020): 113008. http://dx.doi.org/10.1016/j.comptc.2020.113008.

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37

Yang, Zan, Yueqiao Yan, An Li, Jiashu Liao, Lei Zhang, Tao Yang, and Congshan Zhou. "Iodine-mediated sulfenylation of 4-hydroxycoumarins with sulfonyl hydrazides under aqueous conditions." New Journal of Chemistry 42, no. 18 (2018): 14738–41. http://dx.doi.org/10.1039/c8nj03461c.

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An efficient, metal-free approach to the synthesis of sulfenylated coumarins based on the iodine catalyzed regioselective sulfenylation of 4-hydroxycoumarins with arylsulfonyl hydrazides was developed under mild conditions in water.

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38

Sharma, Suraj, Bipul Sarma, and Gakul Baishya. "Direct synthesis of 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone containing chroman-4-ones via a silver catalyzed radical cascade cyclization reaction." New Journal of Chemistry 45, no. 34 (2021): 15475–86. http://dx.doi.org/10.1039/d1nj03437e.

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39

Nykolov, Nykolay, Tanya Iossifova, Elka Vassileva, Ivanka Kostova, and Georgi Stoev. "Reverse-phase high pressure liquid chromatographic analysis of hydroxycoumarins in plant extracts. Quantitative determination of hydroxycoumarins inFraxinus ornus." Phytochemical Analysis 4, no. 2 (March 1993): 86–88. http://dx.doi.org/10.1002/pca.2800040207.

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40

Berg, Marian de Boer-van den, Henk H. W. Thijssen, and Cees Vermeer. "The In Vivo Effects of Oral Anticoagulants in Man: Comparison Between Liver and Non-Hepatic Tissues." Thrombosis and Haemostasis 59, no. 02 (1988): 147–50. http://dx.doi.org/10.1055/s-0038-1642744.

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SummaryThe in vivo effects of oral anticoagulant therapy with 4–hydroxycoumarins on various vitamin K–dependent enzyme systems in man were compared. In hepatic microsomes obtained from donors who has been treated with 4–hydroxycoumarins for more than 6 months, the vitamin K 2,3 epoxide reductase activity and the DTT–dependent vitamin K quinone reductase activity were diminished to 35% and 20% of the corresponding normal values. In the non–hepatic tissues, only a small decrease in vitamin K 2,3 epoxide reductase activity could be demonstrated, while no differences were found in the vitamin K quinone reductase activities. In none of the tissues a significant increase of non–carboxylated precursor proteins was observed, whereas also vitamin K hydroquinone–dependent carboxylase activities seemed to be unaffected by the anticoagulant treatment.

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41

Gong, Lingzhen, He Zhao, Jian Yang, Huanfeng Jiang, and Min Zhang. "Selective construction of fused heterocycles by an iridium-catalyzed reductive three-component annulation reaction." Chemical Communications 57, no. 67 (2021): 8292–95. http://dx.doi.org/10.1039/d1cc03332h.

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Herein, we report a catalytic reductive three-component annulation reaction for the construction of fused heterocycles featuring a pyrano[2,3-b]pyridyl motif from N-heteroarenium salts and formaldehyde with cyclic 1,3-diketones or 4-hydroxycoumarins.

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42

Raunio, Hannu, Olli Pentikäinen, and Risto O. Juvonen. "Coumarin-Based Profluorescent and Fluorescent Substrates for Determining Xenobiotic-Metabolizing Enzyme Activities In Vitro." International Journal of Molecular Sciences 21, no. 13 (July 1, 2020): 4708. http://dx.doi.org/10.3390/ijms21134708.

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in vivo methods, such as spectrophotometric, fluorometric, mass spectrometric,and radioactivity-based techniques. In fluorescence-based assays, the reaction produces a fluorescentproduct from a nonfluorescent substrate or vice versa. Fluorescence-based enzyme assays areusually highly sensitive and specific, allowing measurements on small specimens of tissues withlow enzyme activities. Fluorescence assays are also amenable to miniaturization of the reactionmixtures and can thus be done in high throughput. 7-Hydroxycoumarin and its derivatives arewidely used as fluorophores due to their desirable photophysical properties. They possess a large -conjugated system with electron-rich and charge transfer properties. This conjugated structure leadsto applications of 7-hydroxycoumarins as fluorescent sensors for biological activities. We describe inthis review historical highlights and current use of coumarins and their derivatives in evaluatingactivities of the major types of xenobiotic-metabolizing enzyme systems. Traditionally, coumarinsubstrates have been used to measure oxidative activities of cytochrome P450 (CYP) enzymes. For thispurpose, profluorescent coumarins are very sensitive, but generally lack selectivity for individual CYPforms. With the aid of molecular modeling, we have recently described several new coumarin-basedsubstrates for measuring activities of CYP and conjugating enzymes with improved selectivity.

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Traven, Valery F., Vadim V. Negrebetsky, Larisa I. Vorobjeva, and Edward Andrew Carberry. "Keto–enol tautomerism, NMR spectra, and H–D exchange of 4-hydroxycoumarins." Canadian Journal of Chemistry 75, no. 4 (April 1, 1997): 377–83. http://dx.doi.org/10.1139/v97-043.

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4-Hydroxycoumarin 1, 4,5-dihydroxycoumarin 2, and 4,7-dihydroxycoumarin 3 undergo H–D exchange at the C(3) atom of the lactone ring. Although only the 4-hydroxy-2-chromenone tautomeric forms are seen in the 1H and 13C NMR spectra of compounds 1–3, the equilibrium between the 4-hydroxy-2-chromenone and 2,4-chromandione forms is suggested to be the key step in the H–D exchange reaction. 4,5-Dihydroxycoumarin shows the highest rate of the reaction, since H-bonding between 5-hydroxyl and 4-keto functional groups can provide relative stability to the 5-hydroxy-2,4-chromandione tautomeric form, a probable intermediate of the exchange. NMR spectra and tautomeric transformations of 3-(4-methoxyphenylazo)-4-hydroxycoumarin 4 and 3-acetyl-4-hydroxycoumarin 5 are also discussed. The stabilities of different tautomeric forms of compounds 1–5 have been evaluated by MNDO calculations. Keywords: 4-hydroxycoumarin derivatives, keto-enol tautomerism, H–D-exchange.

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Veselinović, Jovana, Aleksandar Veselinović, Andrey Toropov, Alla Toropova, Ivana Damnjanović, and Goran Nikolić. "Monte Carlo Method Based QSAR Modeling of Coumarin Derivates as Potent HIV‐1 Integrase Inhibitors and Molecular Docking Studies of Selected 4‐phenyl Hydroxycoumarins." Acta Facultatis Medicae Naissensis 31, no. 2 (June 26, 2014): 95–103. http://dx.doi.org/10.2478/afmnai-2014-0011.

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Summary In search for new and promising coumarin compounds as HIV-1 integrase inhibitors, chemoinformatic methods like quantitative structure-activity relationships (QSAR) modeling and molecular docking have an important role since they can predict desired activity and propose molecule binding to enzyme. The aim of this study was building of QSAR models for coumarin derivatives as HIV-1 integrase inhibitors with the application of Monte Carlo method. SMILES notation was used to represent the molecular structure and for defining optimal SMILES-based descriptors. Molecular docking into rigid enzyme active site with flexible molecule was performed. Computational results indicated that this approach can satisfactorily predict the desired activity with very good statistical significance. For best built model statistical parameters were: a) 3’ Processing activity: R2=0.9980 and Q2=0.9977 for training set and R2=0.9788 for test set and b) Integration activity: R2=0.9999 and Q2=0.9998 for training set and R2= 0.9213 for test set. Built QSAR models were applied to selected 4-phenyl hydroxycoumarins for calculating desired activity and for HIV-1 integrase inhibition estimation. Additionally, molecular docking study was performed to a newly identified pocket in the HIV-1 integrase enzyme structure for determination of selected 4-phenyl hydroxycoumarins binding mode. Monte Carlo method proved to be an efficient approach to build up a robust model for estimating HIV-1 integrase inhibition of coumarin compounds. Based on QSAR and molecular docking studies, 4-phenyl hydroxycoumarins can be considered as promising model compounds for developing new HIV-1 integrase inhibitors.

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Xu, Bowen, Yiping Gao, Jianwei Han, Zejing Xing, Sihan Zhao, Ziyang Zhang, Runlin Ren, and Limin Wang. "Hypervalent Iodine(III)-Mediated Tosyloxylation of 4-Hydroxycoumarins." Journal of Organic Chemistry 84, no. 16 (June 13, 2019): 10136–44. http://dx.doi.org/10.1021/acs.joc.9b01323.

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Appendino, G., G. Cravotto, G. M. Nano, and G. Palmisano. "A Regioselective Synthesis of 3-Isoprenyl-4-Hydroxycoumarins." Synthetic Communications 22, no. 15 (August 1992): 2205–12. http://dx.doi.org/10.1080/00397919208019073.

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Rodríguez, Sergio A., and Maria T. Baumgartner. "A different route to 3-aryl-4-hydroxycoumarins." Tetrahedron Letters 51, no. 40 (October 2010): 5322–24. http://dx.doi.org/10.1016/j.tetlet.2010.08.013.

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Barton, Derek H. R., Dervilla M. X. Donnelly, Jean-Pierre Finet, and Patrick J. Guiry. "A facile synthesis of 3-aryl-4-hydroxycoumarins." Tetrahedron Letters 30, no. 12 (January 1989): 1539–42. http://dx.doi.org/10.1016/s0040-4039(00)99513-3.

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Mulwad, V. V., A. S. Hegde, and V. Suryanarayan. "ChemInform Abstract: Reaction of Hydroxycoumarins and Its Analogues." ChemInform 30, no. 27 (June 14, 2010): no. http://dx.doi.org/10.1002/chin.199927052.

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Frasinyuk, M. S., A. V. Turov, V. I. Vinogradova, and V. P. Khilya. "Aminomethylation of cytisine by 3-hetaryl-7-hydroxycoumarins." Chemistry of Natural Compounds 43, no. 2 (March 2007): 176–80. http://dx.doi.org/10.1007/s10600-007-0073-6.

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