Isolation, evaluation of bioactivity and structure determination of amethinol A, a prototypic amethane diterpene from Isodon amethystoides bearing a six/five/seven-membered carbon-ring system

2018 ◽  
Vol 74 (5) ◽  
pp. 635-640 ◽  
Author(s):  
Chen-Liang Zhao ◽  
Md. Shahid Sarwar ◽  
Jiang-Hai Ye ◽  
Chuen Fai Ku ◽  
Wan-Fei Li ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Structure Determination ◽  
Biosynthetic Pathway ◽  
Biological Activities ◽  
Ring System ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Hydroxy Groups ◽  
Close Contacts

We report the isolation of a novel diterpene, designated as `amethane', from Isodon amethystoides (Lamiaceae). The diterpene [amethinol A; systematic name: (4aR,4bR,7R,10aS)-4b,7-dihydroxy-7-isopropyl-1,1-dimethyl-9-oxododecahydrobenzo[a]azulene-4a(2H)-carboxylic acid], possesses a unique skeleton containing a six/five/seven-membered tricyclic system. Intermolecular O—H...O close contacts were found to the carboxyl, carbonyl and hydroxy groups, connecting molecules into a two-dimensional structure. A possible biosynthetic pathway has been proposed. In addition, the compound was evaluated for its biological activities against different disease targets, and was found to significantly attenuate RORγt-dependent autoimmune responses.

scholarly journals 1-Benzyl-5-bromoindoline-2,3-dione

IUCrData ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Yassine Kharbach ◽  
Youssef Kandri Rodi ◽  
Catherine Renard ◽  
El Mokhtar Essassi ◽  
Lahcen El Ammari
Keyword(s):  
Hydrogen Bonds ◽  
Ring System ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Compound C ◽  
Centroid Distance ◽  
Fused Ring ◽  
Common Plane ◽  
The Mean ◽  
Fused Ring System

In the title compound, C15H10BrNO2, the indoline ring system, the two ketone O atoms and the Br atom lie in a common plane, with the largest deviation from the mean plane being 0.073 (1) Å for the Br atom. The fused-ring system is nearly perpendicular to the benzyl ring, as indicated by the dihedral angle between them of 74.58 (10)°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds and by π–π interactions [inter-centroid distance = 3.625 (2) Å], forming a two-dimensional structure.

scholarly journals Limitations of LEED-Structure Determination of Reconstructed Crystal Surfaces

1982 ◽  
Vol 37 (10) ◽  
pp. 1103-1118 ◽  
Author(s):  
H. Jagodzinski
Keyword(s):  
Structure Determination ◽  
Crystal Surface ◽  
Dimensional Space ◽  
Point Group ◽  
Two Dimensional ◽  
Crystal Surfaces ◽  
Difficult Situation ◽  
3 Dimensional ◽  
Lattice Constants

Although a strictly ordered reconstructed crystal surface may have the two-dimensional symmetry prescribed by the bulk (two-dimensional subsymmetry of the 3-dimensional space group), it belongs more frequently to a subgroup. In the LEED-pattern a lower symmetry of the translation group can easily be detected on account of the superstructure reflections observed. In this case anti-phase domains can hardly be avoided. An even more difficult situation arises if the symmetry of the point group is violated, although the symmetry of the diffraction pattern is not altered at the end of the reconstruction. Twin domains without changes of lattice constants have to be taken into account.Dynamical scattering of anti-phase domains is calculated by applying the "Cluster embedded chain"-method for various distributions of domains. It is shown that the incoherent superposition of scattering amplitudes, normally applied in LEED-calculations may lead to serious errors in structure determination. This effect is even more pronounced for twin domains. As an example we discuss the reconstruction of the (001)-surface of Si and Ge, and show that the wellknown (2 X 1)-structure is an averaged structure only, consisting of anti-phase domains with the (4 x 2)-structure. It may be concluded therefrom that none of the present model structures of this reconstruction agrees with this experimental observation.

scholarly journals Crystal structure of bis(azido-κN)bis(quinolin-8-amine-κ2N,N′)iron(II)

2016 ◽  
Vol 72 (10) ◽  
pp. 1488-1491
Author(s):  
Fatima Setifi ◽  
Dohyun Moon ◽  
Robeyns Koen ◽  
Zouaoui Setifi ◽  
Morad Lamsayah ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Structure Determination ◽  
Crystal Packing ◽  
Octahedral Geometry ◽  
Title Complex ◽  
Two Dimensional ◽  
Azide Ion ◽  
Amine Ligands

The search for new molecular materials with interesting magnetic properties using the pseudohalide azide ion and quinolin-8-amine (aqin, C9H8N2) as a chelating ligand, led to the synthesis and structure determination of the title complex, [Fe(N3)2(C9H8N2)2]. The complex shows an octahedral geometry, with the FeIIatom surrounded by six N atoms; the two N3−anions coordinate in acisconfiguration, while the remaining N atoms originate from the two quinolin-8-amine ligands with the quinoline N atoms lying on opposite sides of the Fe atom. The crystal packing is dominated by layers of hydrophilic and aromatic regions parallel to theacplane, stabilized by a two-dimensional hydrogen-bonded network and π–π stacking.

Sign in / Sign up

Export Citation Format

Share Document