نتایج جستجو برای: coumarin heteroanalougs
تعداد نتایج: 3800 فیلتر نتایج به سال:
In the title compound, C(26)H(26)N(2)O(2)S, the dihedral angle between the benzothia-zole and coumarin rings is 8.34 (7)°, indicating that the overall benzothia-zole substituent is almost coplanar with the coumarin rings. An intra-molecular S⋯O [2.813 (1) Å] contact may help to stabilize the mol-ecular conformation. In the crystal structure, π-π stacking inter-actions [centroid-centroid distanc...
In the title compound, 6-benz-yloxy-2H-1-benzopyran-2-one, C(16)H(12)O(3), the coumarin unit and benzyl plane in the mol-ecule are perpendicular to each other [86.92 (7)°]. The crystal packing is stabilized by π-π stacking inter-actions, with an inter-planar separation between inversion-related coumarin units of 3.618 (3) Å. The crystal structure shows inter-molecular C-H⋯O hydrogen bonding bet...
The effect of adding different volume coumarin dye (5, 15, 25 and 35) ml on optical properties Poly (Methyl Meth Acrylate) was studied. Films pure PMMA with were prepared using the casting technique. Transmission absorption films measured by UV-VIS spectrometer technique type (100 Conc), in order to assess transmission which found an indirect transition. An energy gap is (4.95e v) after (25, ml...
Coumarin is a constituent of many plants. It has found use in industry mainly due to its strong fragrant odour. Coumarin has been used in the treatment of a range of ailments such as cancer, burns, brucellosis and rheumatic disease [l]. The most commonly used quantitative method for coumarin analysis in biological samples is high per formance liquid chromatography (HPLC). However, this method r...
In the fresh tissues of Prunus mahaleb L., three classes of phenolics were characterised: phenolic acid derivatives (main compound being o-coumaric acid glucoside), quercetin glycosides, and anthocyanins (cyanidin 3,5-diglucoside, cyanidin 3-sambubioside, cyanidin 3-xylosyl-rutinoside and cyanidin 3-rutinoside). Coumarin was also identified. The kernels showed a high content of coumarin (0.87 m...
The formation of soluble 1:2 complexes within hydrophilic γ-cyclodextrin (γ-CD) thioethers allows to perform photodimerizations of aromatic guests under controlled, homogenous reaction conditions. The quantum yields for unsubstituted anthracene, acenaphthylene, and coumarin complexed in these γ-CD thioethers were found to be up to 10 times higher than in the non-complexed state. The configurati...
The mechanism of formation of coumarin (1) by Perkin reaction from salicylaldehyde was shown to involve exclusively a basecatalyzed intramolecular aldol-type condensation of O-acetyl salicylaldehyde (2) as an obligatory intermediate followed by dehydration. Direct evidence in support of this contention was provided by the formation of coumarin and 3-phenyl coumarin(5) as the sole products in th...
In the title compound, C15H8O2S, the coumarin moiety is approximately planar (r.m.s. deviation of the 11 non-H atoms = 0.025 Å) and is slightly inclined with respect to the plane of the thio-phen-3-yl ring, forming a dihedral angle of 11.75 (8)°. In the crystal, the three-dimensional architecture features a combination of coumarin-thio-phene C-H⋯π and π-π [inter-centroid distance = 3.6612 (12) ...
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 title compound, C20H14O4, the dihedral angle between the two coumarin ring systems is 52.37 (19)°, showing a gauche arrangement across the C-C bond which links the two units. The carbonyl groups of the two coumarin units adopt an s-trans arrangement. In the crystal, pairs of C-H⋯O hydrogen bonds and π-π inter-actions [centroid-centroid distance = 3.631 (2) Å] connect the mol-ecules into ...
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