نتایج جستجو برای: xanthene
تعداد نتایج: 531 فیلتر نتایج به سال:
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 ...
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...
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 ...
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...
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...
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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