The x-ray crystal structure, resolution and absolute configuration of thecis-?-dichloro(1, 8-diamino-3, 6-diazaoctane)-ruthenium(III) cation

1987 ◽  
Vol 12 (4) ◽  
pp. 361-365 ◽  
Author(s):  
John A. Broomhead ◽  
Nishat A. Pasha ◽  
Carol A. Soloff ◽  
Will L. Steffen ◽  
Meta Sterns
Keyword(s):  
Crystal Structure ◽  
Absolute Configuration ◽  
X Ray

scholarly journals Preparative-scale HPLC Resolution of Metallacyclic η3-Allyltricarbonyliron Complexes and Determination of the Absolute Configuration by X-Ray Crystal Structure Analysis

1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner
Keyword(s):  
Crystal Structure ◽  
Silica Gel ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
Preparative Scale ◽  
X Ray ◽  
The Absolute

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.

scholarly journals Incensfuran: isolation, X-ray crystal structure and absolute configuration by means of chiroptical studies in solution and solid state

RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42357-42362 ◽  
Author(s):  
Najeeb Ur Rehman ◽  
Hidayat Hussain ◽  
Sulaiman Al-Shidhani ◽  
Satya Kumar Avula ◽  
Ghulam Abbas ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Absolute Configuration ◽  
X Ray ◽  
Crude Extracts ◽  
Boswellia Papyrifera

A new cembrane diterpene named incensfuran (1), biogenetically derived from incensole (2), was isolated from crude extracts of the Boswellia papyrifera Hochst.

scholarly journals 5- epi -Incensole: synthesis, X-ray crystal structure and absolute configuration by means of ECD and VCD studies in solution and solid state

2016 ◽  
Vol 27 (17-18) ◽  
pp. 829-833 ◽  
Author(s):  
Satya Kumar Avula ◽  
Hidayat Hussain ◽  
René Csuk ◽  
Sven Sommerwerk ◽  
Phil Liebing ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Absolute Configuration ◽  
X Ray

Crystal-to-Crystal Diastereoselective Transformation of 2,4,6-Triisopropyl-4'-(S)-phenylalaninocarbonylbenzophenone Methyl Ester

1998 ◽  
Vol 54 (6) ◽  
pp. 907-911 ◽  
Author(s):  
H. Hosomi ◽  
Y. Ito ◽  
S. Ohba
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Methyl Ester ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
X Ray Diffraction ◽  
Pass Filter ◽  
X Ray ◽  
Ultra High Pressure ◽  
Phenylalanine Methyl Ester

Dissymmetry of the photoproduct was induced by using a chiral substituent, (S)-methylphenylalanine, in the title compound {N-4-(2,4,6-triisopropylbenzoyl)benzoyl]-(S)-phenylalanine methyl ester (I)}. On irradiation with light from a 250 W ultra-high-pressure Hg lamp for 7 h through a long-pass filter, the photoreaction in a crystal was 100% complete without the loss of crystallinity. The crystal structures (I), before, and (II) {N-[4-(7-hydroxy-3,5-diisopropyl-8,8-dimethylbicyclo[4.2.0]octa-1,3,5-trien-7-yl)benzoyl]-(S)-phenylalanine methyl ester}, after photocyclization, have been determined by X-ray diffraction. For comparison, a crystal structure analysis has also been carried out for the photoproduct (III) of the 3′-COOMe derivative after recrystallization {methyl 3-(7-hydroxy-3,5-diisopropyl-8,8-dimethylbicyclo[4.2.0]octa-1,3,5-trien-7-yl)benzoate}. The dihedral angle between the central carbonyl plane and the triisopropylphenyl ring deviates from 90° by 10 (1)° in (I), which makes an imbalance in the intramolecular O(carbonyl)...H(methine) distances of the isopropyl groups at positions 2 and 6. The crystal structure of (II) indicates that the nearer methine H was predominantly abstracted by the carbonyl O atom in the reaction. The absolute configuration around the asymmetric C atom in the cyclobutenol ring of the product is S.

X-ray crystal structure analysis of a bisepoxide derived from secologanin: the structure and absolute configuration

1983 ◽  
Vol 61 (2) ◽  
pp. 282-283 ◽  
Author(s):  
Stanley C. Nyburg ◽  
Pik Y. Siew ◽  
Gavin N. Saunders ◽  
John R. Purdy ◽  
Stewart McLean
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Dimethyl Acetal ◽  
Crystal Structure Analysis ◽  
Side Chain ◽  
Bench Mark ◽  
Chemical Transformations ◽  
X Ray ◽  
Derivatives Of

The structure and absolute configuration of a bisepoxide (2) produced by oxidation of tetraacetylsecologanin dimethyl acetal (1) with m-chloroperbenzoic acid have been established by X-ray crystal structure analysis. Epoxidation of the vinyl side chain is unexceptional; epoxidation of the β-alkoxyacrylate moiety is novel. This determination represents a valuable bench mark for configurational assignments, since the bisepoxide has been correlated by chemical transformations with a number of synthetic and naturally-occurring derivatives of secologanin.

Molecular Structure of cis- and trans-Tergurides

1998 ◽  
Vol 63 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Petr Sedmera ◽  
Vladimír Havlíček ◽  
Hana Votavová ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Absolute Configuration ◽  
Catalytic Hydrogenation ◽  
Ergot Alkaloid ◽  
Cd Spectra ◽  
X Ray ◽  
Relative Stereochemistry ◽  
Cis And Trans

Four isomers of terguride, a semisynthetic ergot alkaloid derivative, have been prepared by catalytic hydrogenation of (5R,8S)- and (5S,8S)-lisuride [1,1-diethyl-3-(6-methyl-8-ergolenyl)urea]. Relative stereochemistry of the isomers is based on NMR and CD spectra. Absolute configuration of all the series has been confirmed by the X-ray crystal structure determination of (5R,8S,10S)-terguride 2-bromobenzoate [1,1-diethyl-3-(6-methyl-8-isoergolenyl)urea, cis-dihydrolisuride].

scholarly journals Crystal structure of 5-[(benzoyloxy)methyl]-5,6-dihydroxy-4-oxocyclohex-2-en-1-yl benzoate

2020 ◽  
Vol 76 (7) ◽  
pp. 1096-1100
Author(s):  
Theerachart Leepasert ◽  
Patchreenart Saparpakorn ◽  
Kittipong Chainok ◽  
Tanwawan Duangthongyou
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Natural Product ◽  
Dihedral Angle ◽  
Absolute Configuration ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ring Form

The crystal structure of the natural product zeylenone, C21H18O7, was confirmed by single-crystal X-ray diffraction. The crystal structure has three chiral centers at positions C1, C5 and C6 of the cyclohexanone ring, but the absolute configuration could not be determined reliably. The methyl benzoate and benzoyloxy substituents at positions C1 and C5 of the cyclohexenone ring are on the same side of the ring with the dihedral angle between their mean planes being 16.25 (10)°. These rings are almost perpendicular to the cyclohexenone ring. The benzoate groups and two hydroxyl groups on the cyclohexenone ring form strong hydrogen bonds to consolidate the crystal structure. In addition, weak C—H...O hydrogen bonds also contribute to the packing of the structure.

Troponoid. V. Crystallographic studies on AY-27110 — a dopamine agonist of the troponylpiperazine series

1982 ◽  
Vol 60 (21) ◽  
pp. 2687-2691 ◽  
Author(s):  
Farid Ramadan Ahmed ◽  
Jehan Bagli
Keyword(s):  
Crystal Structure ◽  
Dopamine Agonist ◽  
Absolute Configuration ◽  
Piperazine Ring ◽  
Chair Form ◽  
X Ray

The crystal structure and absolute configuration of a p-bromobenzoyl derivative, 2, of the (−)2-[4-[2-hydroxy-2-(3′,4′-dimethyl-phenyl)ethyl]-1-piperazinyl]-2,4,6-cycloheptatrien-1-one, 3a (AY-27110), which is a dopamine agonist, have been determined by an X-ray analysis. Crystals of C28H29BrN2O5, fw = 553.47, are monoclinic P21, a = 12.553(2), b = 6.359(1), c = 17.575(3) Å, β = 108.32(1)°, V = 1331.81 Å3, Z = 2, ρc = 1.380, ρo = 1.384 g cm−3. For 2155 observed reflexions, the final R is 0.036 and R(w) is 0.039. The chirality of this enantiomer is shown to be S(−), based on 18 reflexions with significant differences in the intensities of the corresponding Friedel pairs. The piperazine ring has a distorted chair form that is flattened at the N atom nearest the cycloheptatriene ring as for the psychoactive agents loxapine and amoxapine.

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