Umbelliferone derivatives

T. M. Li, J. L. Benovic, and J. F. Burd, Serum theophylline determination by fluorescence polarization im+munoassay utilizing an umbelliferone derivative as a fluorescent label, Anal. Biochem. 118, 102-107 (1981). 

BIOTRANSFORMATIONS OF 4-METHYL UMBELLIFERONE DERIVATIVES - FUNGAL MEDIATED O-DEALKYLATIONS. 

B (NP-PEG reagent, UV-365 nm). The characteristically polar co.i-npound in Mezerei cortex (1) is triurabellin seen as a prominent blue zone at Rf 0..55 as well as five to six weak blue-violet fluorescent umbelliferone derivatives in the R, range 0.2-0.4. The yellow-brown zone of daphnetin (Tl) moves up to the solvent front. 

The decay time of the fluorophor used as label should be longer than the rotational time of the hapten but shorter than the rotational time of the complex formed. Fluorescein, which has a fluorescence lifetime of 4.5 ns, or rhodamine are the most frequently used fluorophors. For larger antigens, fluorophors with somewhat longer decay times such as Lucifer yellow, dansyl, and umbelliferone derivatives have been tested. In a typical competitive format, the degree of polarization is inversely proportional to the concentration of the analyte. 

They also state that analytical studies of the oxidation products of dichroine-a indicate that the dichroines are quinazoline derivatives, as already indicated by Koepfli et al. for their alkaloids. With the probable exception of dichroine-a, these bases are active against malaria in chicks in the descending order dichroine-y (1), dichroine- (4) dichroidine quinazolone (40) the figures in brackets are effective doses (mgm./kilo.). There are also two neutral substances present, umbelliferone (dichrin-A) and dichrin-B, m.p. 179-181°. 

Umbelliferone, pH-dependent change of fluorescence color 44 Universal reagents 4,46,195,376,402,405, 412, 430, 434 Uracil derivatives 44,45 Uranium cations 144 Uranyl acetate reagent 44 Urea... 

Relatively few probes have been widely applied to FlAs. Fluorescein and rho-damine, their derivatives, and to some extent phycoerythrin have dominated immunoassays that are based on steady-state measurements. Dansyl, umbelliferone, coumarins, and pyrenes are among others that have been used. Several more commonly used dyes are shown in Figure 14.2. Shorter-wavelength dyes tend to be less useful since they excite at wavelengths where endogenous chromophores, fluorophores, and... 

Other flavones in passionflower (vitexin, coumerin, umbelliferone) have not been well characterized for their neuropharmacological action. Vitexin (derived from millet in one study) was found to have antithyroid properties. The remaining constituents, maltol and harman alkaloids, are present in small quantities and not presumed to contribute to the psychotropic effects (Meier 1995). Harman alkaloids in greater quantities are hallucinogenic and presumed to work through 5-HT receptors (Grella et al. 1998). 

FA003 Hofer, O., M. Widhalm, and H. Greger. Circular dichroism of ses-quiterpene-umbelliferone ethers and structure elucidation of a new derivative isolated from the gum resin asafetida . Monatsh Chem 1984 115(10) 1207-1218. 

Coumarins and isocoumarins appear to be of varied origins. Simple coumarins, such as umbelliferone, are formed by the shikimic acid pathway in which hydroxylation of p-hydroxycinnamic acid occurs. Other coumarins, for example alternariol (690), are derived from a polyketide unit, as are a number of chromanones, chromones, pyranones and isocoumarins (B-78MI22400). The biosynthesis of 5-hydroxy-2-methylchromone has been shown to involve the chromanone (60JCS654). However, isocoumarins are also derived from the mixed acetate-shikimate route, through initial cyclization of the polyketide and subsequent lactonization. 

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. 

Many other natural coumarins have a more complex carbon framework and incorporate extra carbons derived from an isoprene unit (Figure 4.33). The aromatic ring in umbelliferone is activated at positions ortho to the hydroxyl group and can thus be alkylated by a suitable alkylating agent, in this case dimethylallyl diphosphate. The newly introduced dimethylallyl... 

Coumarins are natural compounds that contain characteristic benzo[a]pyrone (2H-benzopyran-2-one) moiety. They are especially abundant in UmbelUferae, Rutaceae, Leguminosae, and other plant families. Different coumarin derivatives have been isolated. Usually the substituents are at the positions C5, Cg, C7, and Cs [e.g., umbelliferone (7-hydroxycoumarin), hier-niarin (7-methoxycoumarin), esculetin (6,7-dihydrox-ycoumarin), scopoletin (6-methoxy-7-hydroxy-coumarin), osthenol (7-hydroxy-8-prenylcoumarin), osthol (7-methoxy-8-prenylcoumarin), and others]. 

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