نتایج جستجو برای: xanthene

تعداد نتایج: 531  

2011
Sayed Hasan Mehdi Othman Sulaiman Raza Murad Ghalib Chin Sing Yeap Hoong-Kun Fun

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 ...

2008
Mehmet Akkurt Aliasghar Jarrahpour Edris Ebrahimi Mustafa Gençaslan Orhan Büyükgüngör

In the title compound, C(39)H(25)NO(2)·0.5C(6)H(14), the β-lactam ring is nearly planar [maximum deviation of 0.012 (2) Å from the mean plane] and makes dihedral angles of 36.41 (13), 88.87 (13) and 54.16 (12)°, respectively, with the naphthalene, xanthene and anthracene ring systems. The mol-ecular conformation is stabilized by intra-molecular C-H⋯O and C-H⋯N contacts. The complete solvent mol...

2012
Hoong-Kun Fun Chin Wei Ooi B. Palakshi Reddy V. Vijayakumar S. Sarveswari

In the title compound, C(20)H(22)O(5), the tetra-hydro-pyran, cyclo-hexene and cyclo-hexane rings of the xanthene ring system adopt half-chair, half-boat and chair conformations, respectively. The mean plane of the four roughly planar atoms of the tetra-hydro-pyran ring (r.m.s. deviation = 0.111 Å) forms a dihedral angle of 82.91 (4)° with the meth-oxy-benzene group. In the crystal, mol-ecules ...

Journal: :iranian journal of catalysis 0
javad safaei-ghomi department of chemistry, qom branch, islamic azad university, qom, i. r. iran. jalal shapoori department of chemistry, qom branch, islamic azad university, qom, i. r. iran. mohammad ali ghasemzadeh department of chemistry, qom branch, islamic azad university, qom, i. r. iran.

in this study, cui nanoparticles as an efficient catalyst was used for the synthesis of 14-phenyl-8h-dibenzo[a,i]xanthene-8,13(14h)-diones using aldehydes, 2-naphthol and 2-hydroxynaphthalene-1,4-dione in aqueous media. in this study, it was found that water was the most effective solvent compared to others. among several catalysts that were tested for this multi-component synthesis, cui nanopa...

Journal: :Organic & biomolecular chemistry 2009
Denys Meshcheryakov Michael Bolte Volker Böhmer

Two cyclic oligoureas with 64- and 80-membered rings in which two sets of three or four rigid xanthene (X) units are connected via flexible diphenyl ether (D) units were synthesized by a stepwise fragment condensation. The compounds were characterized by (1)H NMR and ESI mass spectrometry. The structure of the cyclic octamer (XXXDXXXD) was additionally confirmed by single crystal X-ray analysis...

2009
Paweł Niedziałkowski Tadeusz Ossowski Artur Sikorski

The crystal structure of the title compound, C(16)H(12)O(5), is stabilized by C-H⋯O hydrogen bonds and C=O⋯π inter-actions; π-π inter-actions are also present. With respective average deviations from planarity of 0.003 (2) and 0.002 (1) Å, the xanthone and ester fragments are oriented at an angle of 2.8 (2)° with respect to each other. The mean planes of the xanthone skeleton lie either paralle...

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