نتایج جستجو برای: chromene

تعداد نتایج: 842  

2011
Afsheen Arshad Hasnah Osman Chan Kit Lam Madhukar Hemamalini Hoong-Kun Fun

In the title compound C(19)H(11)N(3)O(2)SClBr·C(2)H(6)OS, the mol-ecule adopts an E configuration about the central C=N double bond. The chromene ring system and the thia-zole ring are approximately planar, with maximum deviations of 0.027 (2) and 0.003 (1) Å, respectively. The central thia-zole ring makes dihedral angles of 21.82 (9) and 5.88 (7)° with the chloro-substituted phenyl ring and th...

2011
Afsheen Arshad Hasnah Osman Chan Kit Lam Madhukar Hemamalini Hoong-Kun Fun

In the title compound, C(19)H(11)N(3)O(2)SClBr, the chromene ring system and the thia-zole ring are each approximately planar, with maximum deviations of 0.033 (3) Å and 0.006 (3) Å, respectively. The mol-ecule adopts an E configuration about the central C=N double bond. The central thia-zole ring makes dihedral angles of 9.06 (14)° and 12.07 (11)° with the chloro-substituted phenyl ring and th...

2010
Afsheen Arshad Hasnah Osman Chan Kit Lam Ching Kheng Quah Hoong-Kun Fun

In the title compound, C(19)H(12)FN(3)O(2)S, the chromene ring system and the thia-zole ring are approximately planar [maximum deviations of 0.023 (3) Å and 0.004 (2) Å, respectively]. The chromene ring system is inclined at angles of 4.78 (10) and 26.51 (10)° with respect to the thia-zole and benzene rings, respectively, while the thia-zole ring makes a dihedral angle of 23.07 (12)° with the b...

2011
Michał Wera Ilia E. Serdiuk Alexander D. Roshal Jerzy Błażejowski

In the title compound, C(16)H(12)O(4), the benzene ring is twisted at an angle of 12.3 (1)° relative to the 4H-chromene skeleton, and an intramolecular O-H⋯O hydrogen bond occurs. The meth-oxy group is almost coplanar with the benzene ring [1.5 (1)°]. In the crystal, inversely oriented mol-ecules are arranged in double (A, A') columns, along the b axis, and are linked by a network of inter-mole...

2013
Lin-Jie Yan Sheng-Yong Zhang

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar (r.m.s. deviation from planarity = 0.0888 Å). The di-hydro-pyran ring adopts an envelope conformation with the phenyl-substituted C atom fused to the di-hydro-pyran ring as the flap. The dihedral angle between the plane defined by this C atom and the adjacent C and O atoms and the mean plane of the di-hydro-pyran ring exc...

2015
Nilanjana Majumdar Nanda D. Paul Sutanuva Mandal Bas de Bruin William D. Wulff

2H-Chromenes (2H-1-benzopyran derivatives) display a broad spectrum of biological activities. The 2H-chromene substructure is an important structural motif present in a variety of medicines, natural products, and materials showing unique photophysical properties. Hence, the structural importance of the benzopyran moiety has elicited a great deal of interest in the field of organic synthesis and...

Journal: :Chemical communications 2015
Hideki Abe Yuri Horii Megumi Hagiwara Toyoharu Kobayashi Hisanaka Ito

Stereoselective construction of the highly oxygenated decahydrocyclopenta[g]chromene skeleton, which is the tricyclic core of leucosceptrine, which possesses prolylendopeptidase inhibitory activity, and leucosesterterpenone, which exhibits anti-angiogenic activity, from Leucosceptrum canum, was achieved.

Journal: :Organic & biomolecular chemistry 2011
Yan-Chao Wu Hui-Jing Li Li Liu Zhe Liu Dong Wang Yong-Jun Chen

The treatment of β,γ-unsaturated α-ketoesters with phenols in the presence of trityl chloride and 4 Å molecular sieves in refluxing trifluoroacetic acid afforded 4-aryl-2H-chromenes in high yields, in which a reverse of the regiochemistry of Jørgensen-Rutjes chromane synthesis was observed. The isolation of 4H-chromene intermediates, confirmed by single-crystal X-ray analysis, indicates that th...

2014
K. Ravi Shankar N. Sita Ratna Kumari

A new molecule of 2-[3, 4 di hydroxy phenyl] 3, 5, 14-trihydroxy 13oxo 2H-chromeno [34:5, 6] pyrano [2, 3-h] 4H-chromene 4-one was synthesized and screened. This new compound was synthesized by incorporating 4-chloro-3-formyl coumarin group with quercetin compound. In the present study the antioxidant and antimalarial activities of new 2-[3, 4 di hydroxy phenyl] 3, 5, 14-trihydroxy 13oxo 2H-chr...

Ali Reza Berenji Hadi Behzadi Hossein Eshghi Maesam Raeisian Mohammad Vakili, Raheleh Afzali

Two possible isomers of some 1,3-diaryl-H-benzo[f]chromene have been studied using density functional theory. Structures of E1 and E2 isomers were optimized at the B3LYP and MP2 levels with different basis sets. The total electronic energies show that E2 isomer is about 3-5 kcal/mol more stable than E1 isomer and this energy difference is attributed to the planarity of heterocyclic ring and mor...

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