No abstract

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.

Important areas such as environmental sciences, medicine, pharmacy, and cellular biology are dependent on very sensitive analytical techniques. One of the most common methodologies used for their bioanalytical purposes is the fluorescent labelling. The synthesis of new fluorophores and the great development of fluorescent-labelling techniques combined with the enormous technological advances in the field of fluorescence microscopy allowed to deepen the structural knowledge of biomolecules. This new organic fluorophores form covalent bonds with the sample to be analyzed, producing stable bioconjugates that show fluorescence in a wide range of wavelengths, depending on the label used. Coumarin derivatives represent one of the most important chemical classes of organic fluorescent materials being one of the most extensively investigated and commercially significant groups of organic fluorescent materials. In this chapter, it is reviewed the use of fluorescent coumarin derivatives and their application to labelling biomolecules. These fluorescent labels allow researchers to study, and understand, biomolecular assemblies that exhibit complex sensitivity and selectivity. Reactive fluorescent coumarin derivatives are actually widely used in labelling biomolecules as peptides, proteins, oligonucleotides, nucleic acids, and carbohydrates, among other biological molecules.

New Methodology for the Synthesis of 3-Substituted Coumarins via Palladium--Catalyzed Site-Selective Cross-Coupling Reactions. -(MARTINS, S.; BRANCO, P. S.; DE LA TORRE, M. C.; SIERRA, M. A.; PEREIRA*, A.; Synlett 2010, 19, 2918-2922, http://dx.doi.org/10.1055/s-0030-1259014 ; Dep. Quim., Univ. Evora, P-7000 Evora, Port.; Eng.) -M. Haryono 14-159

No abstract

Easel paintings are assets with an important historic and cultural value. They usually possess a multi-tiered structure, composed of different layers some of which may present protein binders, making it important to identify these materials for restoration and conservation purposes. We propose the identification of different protein binders by a new fluorescent labeling method employing a coumarin based chromophore, C392STP (sodium(E/Z)-4-(4-(2-(6,7-dimethoxycoumarin-3-yl)vinyl)benzoyl)-2,3,5,6-tetrafluorobenzenesulfo-nate). The method was optimized using commercial proteins and was further tested on proteins extracted from hen’s egg yolk, white bovine milk, and rabbit skin glue. To model more realistic conditions, paint models of easel paintings were prepared. The paint models were made with hen’s egg yolk, white bovine milk, and rabbit skin glue, mixed with different pigments and submitted to artificial aging. Then the extracted proteins from the paint models were labeled with C392 which allowed a sensitive and selective identification by polyacrylamide gel electrophoresis (PAGE) of the different protein binders used. As a final test, three 19th century easel paintings, from the Italian painter Giorgio Marini, were analyzed. The results show the potential of the proposed method for the identification of protein binders present in easel paintings.

No abstract

Keeping it in the family: A new family of 5‐styrylcoumarins exhibit E–Z isomerization around the CαCβ bond with large extinction coefficients, medium‐lived excited states, and moderate fluorescence quantum yields (see picture). The alteration of these photophysical properties is also corroborated by computational studies.