PhAs(C5H4)2TiCl2: Das erste Arsen-überbrückte Titanocenophan / PhAs(C5H4)2TiCl2: The First Arsenic-Bridged Titanocenophane

1991 ◽  
Vol 46 (5) ◽  
pp. 647-649 ◽  
Author(s):  
Nikolaos Klouras
Keyword(s):  
Low Temperature ◽  
Nmr Spectrum ◽  
Stable Compound ◽  
H Nmr ◽  
Temperature Conditions

By reacting PhAsCl2 with NaC5H5 in toluene under low temperature conditions PhAs(h1-C5H5)2 was obtained. Metallation of PhAs(h1-C5H5)2 with n-BuLi followed by reaction with TiCl4 led to the As-bridged [1]titanocenophane. The structure and conformation of this air-stable compound are discussed in the light of its 1H NMR spectrum.

Beiträge zur Chemie des Phosphors, 234 [1,2] Lithium-tetrahydrogencyclopentaphosphid: Synthese, Struktur und Reaktionen / Contributions to the Chemistry of Phosphorus, 234 [1,2] Lithium Tetrahydrogen Cyclopentaphosphide: Synthesis, Structure and Reactions

1995 ◽  
Vol 50 (5) ◽  
pp. 786-790 ◽  
Author(s):  
Marianne Baudler ◽  
Rudolf Heumüller ◽  
Wolfgang Faber
Keyword(s):  
Low Temperature ◽  
Complete Analysis ◽  
Lemon Yellow ◽  
Compound I ◽  
Polar Solvents ◽  
Open Chain ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Nmr Parameters ◽  
Reaction Compound

Abstract Lithium tetrahydrogen cyclopentaphosphide. LiH4P5 (I). has been obtained by metalation of P2H4 at -78 °C with either n-BuLi or LiPH2 in polar solvents. Upon suitable performance of the reaction, compound I can be isolated at low temperature as a lemon-yellow solvent adduct. The structure as the monolithium salt of (PH)5 was confirmed by a complete analysis of the 31P{1H}-NMR spectrum. On warming above -35 °C, disproportionation occurs yield­ing Li2HP7. P2H4. and PH3. The reaction with n-BuLi produces the open-chain phosphides LiH4P3. LiH3P2, and LiPH2. The NMR parameters of LiH3P2 and LiH4P3 are reported. Reac­tion of 1 with P2H4 gives rise to the bicyclic and polycyclic phosphides LiH4P7, LiH5P8 and Li2H2P14, respectively.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

scholarly journals Structural studies of phosphorylation-dependent interactions between the V2R receptor and arrestin-2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qing-Tao He ◽  
Peng Xiao ◽  
Shen-Ming Huang ◽  
Ying-Li Jia ◽  
Zhong-Liang Zhu ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Conformational Changes ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Interaction Sites ◽  
Receptor Interactions ◽  
Remote Sites ◽  
Genetic Code Expansion ◽  
G Protein Coupled ◽  
Interaction Change

AbstractArrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.

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