Coumarin derivatives, fluorescent

Advances in coumarin-derived fluorescent chemosensors for metal ions 12COC2690. 

Elastase release from dense granules is monitored with a nonfluorescent substrate containing a coumarin derivative. When the substrate is cleaved, fluorescent aminomethylcoumarin is released. 

The resulting coumarin derivatives were isolated with >99% purity using the automated LC/MS purification system. Although there were neither rational explanation nor deduced structure-photophysical property relationships, this study successfully demonstrated the application of a combinatorial approach for the development of novel fluorescent compounds. The systematic transformation of... 

Rangaswami S, Seshadri TR, Venkateswarlu V (1941) The remarkable fluorescence of certain coumarin derivatives. Proc Ind Acad Sci 13A 316-322... 

DCIA is 7-diethylamino-3-[(4 -(iodoacetyl)amino)phenyl]-4-methylcoumarin, a derivative of the basic aminomethylcoumarin structure that contains a sulfhydryl-reactive iodoacetyl group and a diethyl substitution on its amine. This particular coumarin derivative is among the most fluorescent UV-excitable iodoacetamide probes available (Sippel, 1981) (Invitrogen). 

For the reaction-based sensing of anions, the most considerable success has been reached in cyanide sensing, basically due to the necessity for assessing this toxic species and because it can be easily addressed in water due to its high nucleophi-licity. For instance, the coumarin derivative 50 shows a dramatic fluorescence increase after cyanide-induced cyanohydrin reaction (Fig. 19), no response to... 

Coumarins, too, fluoresce, notably when an electron-releasing group is present at the 7-position. For example, A-acyl derivatives of some 7-aminocoumarins serve as fluorescent markers for the detection of proteinases (80MI22403). Coumarins show a propensity to absorb UV light and this results in a number of applications. A particularly simple illustration is the use of umbelliferone, 7-hydroxycoumarin, in sun-screen lotions. 

Fluorescence detection was employed for quantitation of coumarins because of sensitivity and specificity. However, monitoring the fluorescence at one wavelength was not sufficient to observe all of the coumarin derivatives. A wide range of fluorescence maxima (314-346 nm for excitation and 420 -517 nm for emission) for coumarins are also utilized possibly to identify the individual components and selectively to enhance the fluorescence of coumarins in citrus oils (25). 

Antibodies labeled with fluorescent molecules have several applications, particularly in cytochemistry and cell sorting. There are many fluorochromes used in labeling (1), such as coumarin derivatives, phycobiliproteins, and rare earth chelates however, fluorescein and rhodamine (Table 1) are the most commonly used. 

Cationic dyes are occasionally used fur blueing or brightening the hair, frequently in combination with a fluorescent dyes. P. Krais discovered the brightening effect in 1929 by impregnation of rayon with a horsechestnut extract known as esculin, a fluorescent glycoside of 6,7-dihydroxycoumarin. Coumarin derivates are still used for wool and fur hair. 

Fig. 5.10 3-Substituted coumarin derivatives 26 with high fluorescence quantum yields identified by screening of substance libraries.

Certain fluorescent compounds, such as the coumarin derivative, scopoletin, can act as hydrogen donors in the oxidative reaction catalysed by horseradish peroxidase (Udenfriend, 1969), an enzyme that exhibits substrate specificity for hydrogen peroxide... 

The effect of an electrical field on the absorption/emission of spectra of a probe such as fluorescein or a coumarin derivative. It is derived from the interaction of the induced dipole(s) in the probe interacting with the charged group. See Sitkoff, D., Lockhart, D.J., Sharp, K.A., and Honig, B., Calculation of electrostatic effects at the amino terminal of an helix, Biophys. J. 67,2251-2260,1994 Pierce, D.W. and Boxer, S.A., Stark effect spectroscopy of tryptophan, B/opfiyx. J. 68,1583-1591,1995 Klymchenko, A.S., Avilov, S.V., and Demchenko, A.P., Resolution of Cys and Lys labeling of a-crystalUn with site-sensitive fluorescent 3-hydroxyflavone dye. Anal. Biochem. 329, 43-57, 2004. 

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