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 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.

Crystal and Molecular Structure of 4-Arylhexahydro-1H,3H-pyrido[1,2-c]pyrimidine-1,3-dione Derivatives

2002 ◽  
Vol 57 (11) ◽  
pp. 1315-1319 ◽  
Author(s):  
Irena Wolska ◽  
Franciszek Herold
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Determination ◽  
Phenyl Ring ◽  
Crystal And Molecular Structure ◽  
X Ray ◽  
Saturated Ring ◽  
Centrosymmetric Dimers

The X-ray crystal structure determination of 4-(2-methylphenyl)hexahydro-1H,3H-pyrido[ 1,2-c]pyrimidine-1,3-dione (2) and 4-(3-methylphenyl)hexahydro-1H,3H-pyrido[1,2-c]- pyrimidine-1,3-dione (3) is reported. The crystal structures show the formation of centrosymmetric dimers via intermolecular N-H···O hydrogen bonds. The saturated ring adopts a slightly distorted halfchair conformation in both 2 and 3. In either compound the planar phenyl ring is twisted with respect to the pyrimidine-1,3-dione fragment.

scholarly journals X-Ray crystal structure of [(?-H)Os2 (CO)4 (SnPh3)2 (?-HSnPh2) (?-dppf)] (dppf = 1,1´-bis (Diphenylphosphino) ferrocene

2014 ◽  
Vol 38 (1) ◽  
pp. 97-101
Author(s):  
Jagodish C Sarker ◽  
Md Saifur Rahman ◽  
Shariff E Kabir ◽  
Tasneem A Siddiquee
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Structure Determination ◽  
Monoclinic Space Group ◽  
Bimetallic Cluster ◽  
Space Group ◽  
X Ray ◽  
Academy Of Sciences

The solid-state molecular structure determination of the bimetallic osmium-tin compound [(?-H)Os2(CO)4(SnPh3)2(?-HSnPh2)(?-dppf)] (1) was carried out to determine the relative orientationof the coordinated ligands. Compound 1 crystallizes in the monoclinic space group P 21/c with a =22.366(7), b = 14.217(4), c = 25.213(8) Å, ? = 98.865(7)°, Z = 8 and V = 7921(4) Å3. It is a 34-electron bimetallic cluster with the Os-Os edge concomitantly bridged by a dppf and two HSnPh2 ligands DOI: http://dx.doi.org/10.3329/jbas.v38i1.20218 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 97-101, 2014

scholarly journals Sulfur and Selenium Complexes of the Hydrido-tri(3,5-dimethyl-1-pyrazolyl) borate Nitrosylmolybdenum Fragment, [Tp*Mo(NO)]. An X-Ray Crystal Structure Determination of Tp*Mo(NO)(Se5)

1996 ◽  
Vol 51 (5) ◽  
pp. 681-685 ◽  
Author(s):  
Max Herberhold ◽  
Guo-Xin Jin ◽  
Arnold L. Rheingold
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Mass Spectroscopy ◽  
Structure Determination ◽  
Chair Conformation ◽  
Crystal Structure Determination ◽  
X Ray ◽  
Hydrolysis Of

The reactions of hydrido-tri(3,5-dimethyl-1-pyrazolyl)borate nitrosylmolybdenum diiodide, Tp*Mo(NO)I2 (2), with the oligochalcogenides (NH4)2S10 and (NEt4)2Se6 in THF solution lead to mononuclear cyclo-pentachalcogenido complexes, Tp*Mo(NO)(E5) (E = S (3a), Se (3b)). In the presence of either H2S or H2Se (generated by slow “in situ” hydrolysis of AI2E3 in moist THF solution) 2 is converted into binuclear chalcogenido-bridged products, Tp*2Mo2(NO)2(μ-E)2(E = S (4a), Se (4b)) which are more conveniently obtained from 3a,b by dechalcogenation with tri(″butyl)phosphane (1:4,5). The new chalcogen complexes 3a,b and 4a,b were characterized by IR, NMR and mass spectroscopy and compared with the related chalcogen compounds derived from pentamethylcyclopentadienyl nitrosylmolybdenum diiodide, Cp*Mo(NO)l2. The molecular structure of Tp*Mo(NO)(Se5) (3b) has been determined; the complex contains a sixmembered MoSe5; metallacycle in the chair conformation and a linearly coordinated nitrosyl ligand (angle Mo-N-O 178.9(17)°).

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