Results 171 to 180 of about 12,440 (225)
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Acta Crystallographica Section C Crystal Structure Communications, 1996
In xanthene-9-carboxylic acid, C14H10O3, hydrogen bonding is of the cyclic dimer type but involves two crystallographically inequivalent molecules and does not occur about a center of symmetry. The carboxylic H atoms are ordered. The dihedral angle (fold angle) of the xanthene core is 14.2 (1) degree for molecule A and 11.3 (2) degrees for molecule B ...
A C, Blackburn, A J, Dobson, R E, Gerkin
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In xanthene-9-carboxylic acid, C14H10O3, hydrogen bonding is of the cyclic dimer type but involves two crystallographically inequivalent molecules and does not occur about a center of symmetry. The carboxylic H atoms are ordered. The dihedral angle (fold angle) of the xanthene core is 14.2 (1) degree for molecule A and 11.3 (2) degrees for molecule B ...
A C, Blackburn, A J, Dobson, R E, Gerkin
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Revista de Chimie, 2008
This paper examined the synthesis pathways for new compounds starting from raw materials on the anhydride type reacting with polyphenols. The compounds have been characterized through spectral analysis, with estimation yields for each reaction. Basic material syntheses are also presented.
Lucian Iscrulescu +4 more
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This paper examined the synthesis pathways for new compounds starting from raw materials on the anhydride type reacting with polyphenols. The compounds have been characterized through spectral analysis, with estimation yields for each reaction. Basic material syntheses are also presented.
Lucian Iscrulescu +4 more
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Chromatography of Xanthene Dyes
Nature, 1960RECENTLY, Lima and Pieroni1have directed attention to the heterogeneous character of the dye rose bengal, which, when labelled with iodine-131, is used in tests of hepatic function2,3. Applying the ethanol–ammonia solvent system of Ishida et al. 4, they claim resolution of this dye into four components, three coloured and one colourless.
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Porphyrin Architectures Bearing Functionalized Xanthene Spacers
The Journal of Organic Chemistry, 2002A modular synthetic strategy for the construction of cofacial porphyrin architectures bearing hydrogen-bond synthons on a xanthene platform is presented. The convergent approach is based on a xanthene aldehyde-ester building block that is easily obtainable on a multigram scale with minimal purification.
Christopher J, Chang +2 more
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Xanthenes: fluorone derivatives. 1
The Journal of Organic Chemistry, 1992Several new fluorone derivatives including 2,4,5,1-tetraiodo-6-hydroxy-3-fluorone, 2,4,5,1-tetrabromo-6-hydroxy-3-fluorone, and 2,4-diiodo-6-methoxy-3-fluorone were synthesized and their spectral and photophysical properties ...
Jianmin Shi +2 more
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CLEAVAGE OF XANTHENE ETHERS: A NEW ROUTE TO 9-SUBSTITUTED XANTHENES
Canadian Journal of Chemistry, 19649,9-(Tetrachloro-o-phenylenedioxy) xanthene (IIa) and its thio-analogue (IIb) are cleaved by hydrazines to give the corresponding hydrazones of xanthone and thiaxanthone, respectively, together with tetrachlorocatechol. The unsaturated nitriles (Va), (Vb), and (Vc) are produced similarly by the action of malononitrile and cyanoacetic ester ...
N. Latif, I. Fathy, N. Mishriky
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Published as part of Myers, Luke William, Kondratieff, Boris C, Grubbs, Scott A, Pett, Lindsey A, DeWalt, R. Edward, Mihuc, Timothy B & Hart, Lily Veronica, 2025, Distributional and species richness patterns of the stoneflies (Insecta, Plecoptera) in New York State, pp.
Myers, Luke William +6 more
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Myers, Luke William +6 more
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Photophysical characterization of xanthene dyes
Spectrochimica Acta Part A: Molecular and Biomolecular SpectroscopyThe growing interest in using photodynamic therapy for cancer treatment and antimicrobial applications has prompted the search for different classes of dyes. In general, the protocols of these studies are different, making it difficult to compare their efficiency directly.
Eduardo V. Bergmann +6 more
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Xanthenes: Flourone Derivatives II
Tetrahedron Letters, 1993Abstract A series of 9-hydrogen and 9-cyano substituted xanthenes was synthesized and their absorption spectra compared. It was found that the cyano group at the C-9 position can produce large bathochromic shifts (about 100 nm).
Jianmin Shi +2 more
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Journal of Heterocyclic Chemistry, 1987
AbstractThe reaction of 1‐naphthol or phenol derivatives with oxalic and sulfuric acids yielded novel spirolactones. Eight examples (2a‐h) were synthesized by this reaction. The structures of the spirolactones were established from spectral evidence and the X‐ray diffraction studies. Some of the spirolactones form the solvates with the aromatic solvent
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AbstractThe reaction of 1‐naphthol or phenol derivatives with oxalic and sulfuric acids yielded novel spirolactones. Eight examples (2a‐h) were synthesized by this reaction. The structures of the spirolactones were established from spectral evidence and the X‐ray diffraction studies. Some of the spirolactones form the solvates with the aromatic solvent
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