نتایج جستجو برای: αα benzylidene bis4 hydroxycoumarin
تعداد نتایج: 1764 فیلتر نتایج به سال:
Potassium salts of benzylidene and cinnamylidene derivatives malononitrile trimer were obtained by reactions substituted benzaldehydes cinnamaldehydes with in aqueous medium under ultrasonic irradiation. The synthesized showed solid state fluorescence the emission maxima located region λ 528–740 nm, depending on substituent aromatic ring.
Self-immolative aryl phthalate esters were conjugated with cleavable masking groups sensitive to light and hydrogen peroxide. The phthalate linker releases the fluorescent dye 7-hydroxycoumarin upon exposure to light or H2O2, respectively, leading to an increase in fluorescence. The light-sensitive aryl phthalate ester is demonstrated as a pro-fluorophore in cultured S2 cells.
Two new lignan glycosides of dibenzylbutyrolactol type (haplomarin) and arylnaphthalene type (haploborin) were isolated from the aerial parts of Haplophyllumn suaveolens together with the known arylnaphthalene lignan glycoside arabelline and hydroxycoumarin glycoside xeroboside. So far arabelline is found only in H. buxbaunii. This is the first report of the isolation of xeroboside from Haploph...
A new and efficient method has been developed for the synthesis of 4-aryl-7-benzylidene-1,3,4,5,6,7-hexahydro-2H-cyclopenta[d]pyrimidin-2-ones through Biginelli-like reaction of cyclopentanone, with urea/thiourea and aromatic aldehyde employing p-dodecylbenzenesulfonic acid (DBSA) as a recyclable catalyst under solvent-free condition. The recovered catalyst was recycled for further runs. The pr...
We present the next-to-next-to-leading order (αα s) corrections to the first moment of the polarized virtual photon structure function g 1 (x,Q , P ) in the kinematical region Λ ≪ P 2 ≪ Q, where −Q(−P ) is the mass squared of the probe (target) photon and Λ is the QCD scale parameter. In order to evaluate the three-loop-level photon matrix element of the flavor singlet axial current, we resort ...
2-Dimethyl-2H-Chromenes, Coumarin Derivatives, Phase-Transfer Catalysis 2,2-Dimethyl-5H-pyrano(3,2-c)-l-benzopyrano-5-one(2) and 4H-2,3-dihydro-3-methyl-2methylene-furan-l-benzopyran-4-one (3), two new coumarin derivatives were synthesised from 4-hydroxycoumarin by treating with 3-chloro-3-methylbut-l-yne and 3-chlorobut-l-yne respectively, both reactions progressing via the phase-transfer cata...
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 ...
Proteins are the most abundant and diverse class of biomolecules that mediate the vast majority of biochemical processes. The functional units within a protein are the ”domains” which fold autonomously from the rest of the linear amino acid sequence in the protein. Novelty in protein function often arises as a result of gain, loss or re-shuffling of existing domains. Thus, protein domains can a...
To develop novel antimycobacterial agents, a new series of thiazolidinone-azole hybrids 4a-b, 5a-b and 6-13 were designed and synthesized. Thiazolidin-4-ones (4a-b and 5a-b) were obtained by the reaction of Schiff bases and hydrazones (2a-b and 3a-b) with mercaptoacetic acid. 5-Benzylidene derivatives (6-13) were gained by treatment of 5a-b with appropriate benzaldehydes according to Knoevenage...
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