The photochemistry of coumarins

Kuznetsova, N. A.; Kaliya, O. L.

doi:10.1070/rc1992v061n07abeh000992

Cited by 100 publications

(82 citation statements)

References 75 publications

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“…This interest arises from the fact that a variety of natural and synthetic compounds which contain the coumarin substructure exhibit significant biological activities such as inhibitory of platelet aggregation [1], antibacterial [2], anticancer [3], inhibitory of steroid 5a-reductase [4] and inhibitory of HIV-1 protease [5]. For instance, 7-hydroxy 4-methyl coumarin (b-methylumbelliferone) is used as fluorescent brightener, efficient laser dye, standard for fluorometric determination of enzymatic activity and as a starting material for the preparation of insecticide and furano coumarins [6][7][8]. Moreover, coumarins act also as intermediates on the synthesis of fluorocoumarins, chromenes, coumarones, and 2-acylresorcinols [9].…”

Section: Introductionmentioning

confidence: 99%

Pentafluorophenylammonium triflate (PFPAT): An efficient, metal-free and reusable catalyst for the von Pechmann reaction

Montazeri

Khaksar

Nazari

et al. 2011

Journal of Fluorine Chemistry

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Section: Introductionmentioning

confidence: 99%

Pentafluorophenylammonium triflate (PFPAT): An efficient, metal-free and reusable catalyst for the von Pechmann reaction

Montazeri

Khaksar

Nazari

et al. 2011

Journal of Fluorine Chemistry

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“…The details of the data analysis could be referred to the articles. [97][98][99][100][101][102][103][104][105][106][107]110,111 The slow mode in semidilute neutral polymer solutions When the concentration of polymer is higher than the overlap concentration (C*), polymer chains start to 'touch' each other and the solution enters the semidilute regime. C* has been differently defined as 3M/(4pN A R g 3 ), or M/(2 3/2 N A R g 3 ), and [Z] À1 , where M, R g , N A and [Z] are the molar mass, the radius of gyration of polymer chains, the Avogadro constant and the intrinsic viscosity, respectively.…”

Section: Llsmentioning

confidence: 99%

The slow relaxation mode: from solutions to gel networks

Ngai

2010

Polym J

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In the past, many laser light-scattering experimental results revealed that besides the fast relaxation mode, there existed an additional slow mode in semidilute solutions. This slow mode has been assigned to a variety of origins, but there has been no clear and well-accepted explanation. As the polymer concentration increases, the slow relaxation mode persists in the concentrated region, in melts and in gels in which polymer chains are crosslinked instead of entangled. The slow relaxation mode has also been reported for charged macromolecules in aqueous and nonaqueous solutions. However, it is generally thought to be different in nature from that observed in semidilute neutral polymer solution. In recent years, armed with novel solution preparation methods and some specially designed polymers, we have reexamined the dynamics of polymer chains, especially the slow mode, in semidilute neutral polymer solutions, dilute polyelectrolyte solutions and gels, which are reviewed here. Our results suggest that the slow mode can be qualitatively considered as hindered motions of interacting chains even though the nature of interaction can be very different; namely, from the weak segment-segment interaction in a less good solvent to strong electrostatic interaction among polyelectrolyte chains, and even to chemical crosslinking inside gel networks.

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“…5 Depending on the nature and substitution pattern, coumarins show exceptional optical properties, 6 as they constitute the largest class of fluorescent dyes, 7 widely used as emission layers in organic light-emitting diodes (OLED), 8 optical brighteners, 9 nonlinear optical chromophores, 10 fluorescent whiteners, 11 fluorescent labels and probes for physiological measurement 12 and more recently, in labelling 13 and caging. 14 Developments from the last decade show that the introduction of appropriated substituents into the coumarin ring contribute to structures with improved photophysical and spectroscopic proprieties.…”

Section: Introductionmentioning

confidence: 99%

An efficient methodology for the synthesis of 3-styryl coumarins

Martins¹,

Branco²,

Pereira³

2012

J. Braz. Chem. Soc.

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Foi desenvolvida a arilação de Heck, regiosseletiva e altamente eficiente, de 3-vinil-6,7-dimetoxicumarina, para a obtenção de 3-estiril cumarinas com bons a excelentes rendimentos. O aumento da conjugação nos produtos sintetizados reflete na absorvância, revelando todos desvios batocrômicos pronunciados e efeitos hipercrômicos.Regioselective and highly efficient Heck arylation of 3-vinyl-6,7-dimethoxycoumarin has been developed to afford 3-styryl coumarins in good to very high yields. The increase in conjugation reflects on the absorbance of the synthesized compounds revealing all pronounced bathochromic shifts and hyperchromic effects.

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The photochemistry of coumarins

Cited by 100 publications

References 75 publications

Pentafluorophenylammonium triflate (PFPAT): An efficient, metal-free and reusable catalyst for the von Pechmann reaction

Pentafluorophenylammonium triflate (PFPAT): An efficient, metal-free and reusable catalyst for the von Pechmann reaction

The slow relaxation mode: from solutions to gel networks

An efficient methodology for the synthesis of 3-styryl coumarins

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