branes, was measured by the method of Abrams [S]. Endopeptidase activity was measured by incubating 50 pl of each fraction with 450 pI of peptide-coumarin derivative, each at 0.1 11 mM in 50 mM-Tris-HCI, pH 7.5. The release of free 7-amino-4-methylcoumarin was quantified fluorimetrically using excitation and emission wavelengths of 370 nm and 440 nm, respectively. The results obtained for S. cr...

A green one-pot synthesis of 5H-Chromeno[4,3-b]pyridin-5-one derivatives which are the main core natural product Polyneomarline C is described by reaction 4-chloro-3-formyl coumarin and different cyclic acyclic compounds having active methylene group in presence Et3N NH4OAc EtOH. The advantages this strategy good yields, no need for chromatographic separation absence heavy metal catalysts toxic...

A suitable methodology of synthesis of coumarin derivatives by Pechmann reaction over heterogeneous solid acid catalysts in a free solvent media under microwave irradiation is described. Resorcinol, phenol and ethyl acetoacetate were selected as model reactants in the Pechmann condensation. The catalytic activity of several materials-Amberlyst-15, zeolite β and sulfonic acid functionalized hybr...

Six new sesquiterpene coumarin derivatives, fukanefuromarin H-M (1-6), were isolated from an 80% aqueous methanol extract of the roots of Ferula fukanensis. The structures were elucidated on the basis of spectroscopic evidence, particularly heteronuclear multiple-bond connectivity (HMBC) and high-resolution MS. The sesquiterpene coumarin derivatives inhibited nitric oxide (NO) and inducible NO ...

Two quinazolone alkaloids, (+)-febrifugine (1) and isofebrifugine (2), along with three coumarin derivatives, 6-hydroxy coumarin (3), skimmin (5), and umbelliferone-7-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranoside (6), were isolated from the roots of Hydrangea chinensis. Compound 6 is a new compound. In addition, umbelliferone (4), linoleic acid (7), two steroidal glycosides (8, 9), th...

A coumarin-hemicyanine dye was reported for ratiometric fluorescent detection of SO2 derivatives HSO3(-) and SO3(2-) based on a novel addition-rearrangement cascade reaction.

Coumarin is classified as one of interesting therapeutic starting research points to obtain remarkable compounds with high efficacy. So, during this research, new 2-iminochromene derivatives bearing coumarin moiety were synthesized. At first, cyanoacetohydrazone 3-acetylcoumarin was prepared and used the material. The synthesized through ring closure derivative 4-hydroxysalicylaldehyde, 5-aryld...

In the present work we have explored the ultrafast relaxation network of coumarin and umbelliferone (7-hydroxy-coumarin) using time-resolved femtosecond spectroscopy and quantum chemical calculations. Despite the importance of the photophysical properties of coumarin derivatives for applications in biomedicine, the low fluorescence quantum yield of coumarin itself has not been fully understood ...

The synthesis of functionalized 2-oxo-2H-coumarin derivatives has been studied by a one-pot reaction of o-hydroxybenzaldehyde, ethyl 2-bromoacetate and triphenylphosphine in the presence of catalytic amount of triethyl amine in EtOAc, water or under solvent free conditions. We have found the best results obtained under solvent free condition.

In order to extend the photoactivity of titanium dioxide into visible region, highly porous nitrogen-doped TiO2 catalysts (NTiO2) were successfully synthesized by a modified co-precipitation method with ammonium hydroxide as nitrogen source. Different approaches such dosing reagents and temperature synthesis, calcination period tested examine optimum outcome regarding photocatalytic OH radical ...