نتایج جستجو برای: membered rings

تعداد نتایج: 52672  

2011
Xiong-Qing Wang Qin Song Xiao-Qiang Guo Jun Yan

THE TITLE COMPOUND [SYSTEMATIC NAME: 6β,10-dihy-droxy-1α,14α,16β-trimeth-oxy-4-methyl-7β,8-(methyl-enedi-oxy)-20-ethyl-aconitan-6-yl acetate], C(27)H(41)NO(8), is a C(19)-diterpenoid alkaloid and a major diterpenoid alkaloid component of the roots of Delphinium delavayi Franch. var. pogonanthum (Hand.-Mazz.) W. T. Wang. The mol-ecule has a lycoctonine carbon-atom skeleton with four six-membered...

2015
Ahmed Benharref Lahcen El Ammari Mohamed Saadi Noureddine Mazoir Moha Berraho

The title compound, C48H75B3Cl6O3, was synthesized in two steps from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-hept-ene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule consists of an almost planar cyclo-triboroxane ring [maximum deviation = 0.036 (2) Å] linked to three identical fused ring systems with different c...

Journal: :Chemistry 2003
Jordi Poater Xavier Fradera Miquel Duran Miquel Solà

This work introduces a new local aromaticity measure, defined as the mean of Bader's electron delocalization index (DI) of para-related carbon atoms in six-membered rings. This new electronic criterion of aromaticity is based on the fact that aromaticity is related to the cyclic delocalized distribution of pi-electrons. We have found that this DI and the harmonic oscillator model of aromaticity...

2010
Huaxiong Chen Rui Shi Shusen Chen Shaohua Jin Lijie Li Yanshan Shi

The title compound TNDFIW, C(8)H(8)N(10)O(10), is a caged heterocycle substituted with four nitro and two formyl groups. It is related to the hexa-azaisowurtzitane family of high-density high-energy polycyclic cage compounds. Four nitro groups are appended to the four N atoms of the two five-membered rings, while the other two formyl groups are attached to the two N atoms of the six-membered ri...

2007
Xin Yue Jijun Zhao Jieshan Qiu

Density functional theory calculations were performed to investigate the endohedral and exohedral adsorption of a H2 molecule on the classical and nonclassical fullerenes Cx (x=58, 59, 60, 62) with seven-, eight-, and ninemembered rings. The amplitude of adsorption energies are within 0.03eV and the molecule-fullerene interaction belongs to van der Waals type. Penetration of a H2 molecule throu...

2008
Yin-hong Liu Fang-shi Li Yi Li

In the mol-ecule of the title compound, C(17)H(8)Cl(2)F(8)N(2)O(3), the two aromatic rings are oriented at a dihedral angle of 50.12 (3)°. Intra-molecular N-H⋯O, C-H⋯O and N-H⋯Cl hydrogen bonds result in the formation of two six- and one five-membered rings. The six-membered rings have flattened-boat conformations, while the five-membered ring adopts an envelope conformation. In the crystal str...

2009
Jiao-yang Ding Xiao-jie Ren Yan-ping Zhu Neng-fang She An-Xin Wu

The title mol-ecule, C(28)H(28)Cl(4)N(6)O(6), is built up from four fused rings, viz. two nearly planar imidazole five-membered rings which adopt envelope conformations with the C=O groups at the flap position, and two triazine six-membered rings which adopt chair conformations. Each six-membered ring has a 2,4-dichloro-benzyl substituent attached to an N atom. In the mol-ecule, the two ethyl g...

2010
Mohamed Moumou Mohamed Akssira Ahmed El Hakmaoui Lahcen Elammari Ahmed Benharref Moha Berraho

The title compound, C(17)H(22)O(6), was semi-synthesized from 9-hy-droxy-arthenolide, which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule contains fused five- and ten-membered rings: the five-membered lactone ring has a twisted conformation, whereas the ten-membered ring displays an approximate chair-chair conformation. The dihedral angle betwe...

2014
Mohamed Zaki Ahmed Benharref Jean-Claude Daran Moha Berraho

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from two fused seven-membered rings and an additional three-membered ring. I...

2010
Ahmed Benharref Lahcen El Ammari Moha Berraho Esaadia Lassaba

The title compound, C(16)H(22)Cl(2), a derivative of β-himachalene, was semi-synthesized from natural essential oils of Cedrus atlantica. The mol-ecule is built up from two fused six- and seven-membered rings. The six-membered ring has a perfect chair conformation, whereas the seven-membered ring displays a screw boat conformation; the dihedral angle between the rings is 46.48 (9)°.

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