نتایج جستجو برای: pyran derivatives
تعداد نتایج: 106108 فیلتر نتایج به سال:
The title compound, C(26)H(24)O(3), was synthesized via the coupling of 2-methoxy-benzaldehyde, 2-naphthol and 5,5-dimethyl-cyclo-hexane-1,3-dione. The pyran ring adopts a boat conformation, while the cyclo-hexenone ring is in an envelope conformation. The 2-methoxy-phenyl ring is almost perpendic-ular to the plane through the four C atoms of the pyran ring [dihedral angle = 88.76 (9)°].
In the mol-ecule of the title compound, C(16)H(13)N(3)O(4), the atoms of the spiro pyran ring are nearly planar with a maximum deviation of 0.095 (2) Å. The indole and pyran rings are oriented at a dihedral angle of 87.3 (9)°. In the crystal, mol-ecules are linked by inter-molecular N-H⋯N and N-H⋯O hydrogen bonds.
Heating 4-methoxy-1-naphthol with a 1,1-diarylprop-2-yn-1-ol gave the 2,2-diaryl-6-methoxy-2H-naphtho[1,2-b]pyran together with the novel merocyanine, (E)-2-[3',3'-bis(aryl)allylidene]-4-methoxynaphthalen-1(2H)-one. Brief UV-irradiation of the pyran favoured the formation of the (Z)-merocyanine with longer irradiation and/or acidic conditions favouring the (E)-isomer.
The title compound, C(25)H(23)NO(5), comprising two stereogenic carbon atoms of the same configuration, crystallizes in a centrosymmetric space group as a racemate. The six-membered pyran ring and the five-membered isoxazole ring adopt sofa and twisted conformations, respectively. The dihedral angle between the benzene ring and the mean plane through the near coplanar atoms of the pyran ring is...
In the mol-ecular structure of the title compound, C(25)H(21)NO(4), the pyran ring adopts a flattened boat conformation, while the cyclo-hexenone ring is in an envelope conformation. The 4-nitro-phenyl ring is almost perpendicular to the pyran ring [dihedral angle = 89.39 (1)°]. In the crystal, mol-ecules are connected by inter-molecular C-H⋯O hydrogen bonds.
In the title compound, C(26)H(12)FNO(6), the central pyran ring and both benzopyran systems are nonplanar, having total puckering amplitudes of 0.139 (2), 0.050 (1) and 0.112 (2) Å, respectively. The central pyran ring adopts a boat conformation. The crystal structure is stabilized by C-H⋯O, N-H⋯O, N-H⋯F and C-H⋯π inter-actions.
The smoking of foods is one of the oldest methods of preservation. However, foods are nowadays smoked for sensory quality rather than for the preservative effect. Sensory characteristics are one of the important quality attributes that a consumer uses to judge the acceptability of a product. Colours of smoked cheese available in the market range from golden yellow to dark brown, and this array ...
the kinetics and mechanism of the reaction between benzaldehyde 1, malononitrile 2 and dimedone 3 in a mixture of ethanol and water as solvents in the presence of fructose as a biodegradable catalyst has been studied by the spectroscopic method (uv-vis spectrophotometry method). the influence of various parameters (temperature, solvent and concentration) was studied on the reaction by means of ...
An< accurate, stable and very fast corner finder (for feature based vision) has been developed', based on a novel definition of corners, using:no image derivatives. This note describes the algorithm and the results obtained from its use.
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