نتایج جستجو برای: o xanthenes
تعداد نتایج: 554472 فیلتر نتایج به سال:
a green and convenient méthode for the synthesis of a variety of xanthene derivatives by condensation reaction between aldehydes and β-naphthol or dimedone in an micellar solution of sodium dodecylphosphonate is described. this method offers several advantages, such as using of a cheap and environmentally benign reaction media, low loadings of sodium dodecylphosphonate as catalyst and easy wor...
Artičoka (Cynara scolymus L.) je višegodišnja biljna vrsta koja zahvaljujući svojim prehrambenim ali i zdravstvenim značajkama postaje sve raširenija kultura na području primorske hrvatske otoka. Tijekom svog razvoja artičoka podložna napadu brojnih štetnika među kojima su gospodarski značajni nekoliko lisnih ušiju leptira. Lisne uši kao fiziološki štetnici sisanjem listova cvjetnih glavica pos...
The title mol-ecule, rac-6'-bromo-3'-di-ethyl-amino-3H-spiro-[2-benzo-furan-1,9'-xanthen]-3-one, C24H20BrNO3, was synthesized and the two enanti-omers which formed were separated. The structures of all three compounds were determined and compared with those of a variety of related derivatives. A notable feature is the fold of the xanthene portion which ranges from 15.15 (13)° in the racemate to...
Reduction of dixanthylidene with potassium or lithium resulted in formation of the antiaromatic dianion in high yield. Attempts to form the dianion by excited-state deprotonation of dixanthene with n-butyllithium/TMEDA resulted in formation of the tetraanion from deprotonation ortho to the oxygen. Orientation of the sp(3) hydrogens presumably allows preferential deprotonation of the xanthene ri...
The title compound, C(23)H(24)Cl(2)O(3), was synthesized by reaction of 2,4-dichloro-benzaldehyde and 5,5-dimethyl-cyclo-hexane-1,3-dione in ethyl-ene glycol. The central ring of the xanthene moiety is almost planar (with an r.m.s. deviation of 0.0268 Å from the least-squares plane) while the two outer rings, in a cis arrangement, display envelope conformations. The ring of the 2,4-dichloro-phe...
The asymmetric unit of the title xanthene compound, C(25)H(30)O(5), contains two mol-ecules in which the pyran ring and the dimeth-oxy-phenyl ring are nearly perpendicular to one another [dihedral angles = 86.81 (8) and 84.45 (9)°]. One of the meth-oxy groups in one mol-ecule is twisted away from the phenyl ring [C-O-C-C torsion angle = -103.40 (16)°]. The pyran ring adopts a boat conformation ...
The adsorption removal of Triphenylmethane & Xanthene dyes onto a low-cost coal based adsorption (Charfines) and its efficiency in dye colour sorption was compared with activated carbon (F-400). Batch studies were performed and the results revealed that Charfines demonstrated on ability to adsorb the reactive Triphenylmethane & Xanthene dyes. The sorption interaction of reactive dye on to Charf...
The title compound, C(34)H(35)O(2)N(3), was synthesized by the reaction of 2-[3,6-bis-(diethyl-amino)-9H-xanthen-9-yl]benzoyl chloride with aniline. In the mol-ecular structure, the dihedral angles between the isoindoline and xanthene planes and between the isoindoline and benzene planes are 86.9 (3) and 47.0 (2)°, respectively. The mol-ecular packing in the crystal structure is stabilized by w...
The title compound, C(35)H(35)ClN(4)O(3), resulted from a spiro-lactam ring closure of rhodamine B dye. The xanthene ring system is approximately planar [r.m.s. deviation = 0.050 (9) Å for the xanthene ring]. The dihedral angles formed by the spiro-lactam and 5-chloro-2-hy-droxy-benzene rings with the xanthene ring system are 87.9 (7) and 79.1 (7)°, respectively.
this paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (doxos) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. this novel synthetic method has the advantages of high yields, short reaction times, low cost and availabilit...
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