Stereochemical Elucidation of New Sagittamides C - F from a Didemnid Ascidian

2010 ◽  
Vol 63 (6) ◽  
pp. 935 ◽  
Author(s):  
Sarah C. Lievens ◽  
Brandon I. Morinaka ◽  
Tadeusz F. Molinski
Keyword(s):  
Amino Acids ◽  
13C Nmr ◽  
Spectroscopic Data ◽  
Relative Configuration ◽  
Nmr Data ◽  
Tentative Assignment

Four new minor congeners, sagittamides C–F, were isolated from an unidentified Didemnid tunicate that previously afforded sagittamides A and B. The structures were determined by interpretation of spectroscopic data, degradation to amino acids, and comparisons with sagittamide A. An unexpected change in relative configuration of the hexacetoxy C5–C10 stereoelement is present in sagittamides D and F. A tentative assignment of configuration was possible through a systematic deduction based on analysis of 13C NMR data and symmetry considerations.

Synthesis and characteristics of ethylenediamine-N,N'-di-S-α-isovalerate and isomers of its cobalt(III) complexes

1982 ◽  
Vol 47 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Milan Strašák ◽  
František Bachratý ◽  
Jaroslav Majer
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Chemical Parameters ◽  
Methyl Group ◽  
Nmr Data ◽  
Physico Chemical ◽  
Natural Amino Acids ◽  
C Nmr

The synthesis and physico-chemical parameters are described of a new complexone based on natural amino acids, viz. ethylenediamine-N,N'-di-S-α-isovalerate (SS-EDDIV). 1H- and 13C-NMR data revealed that the methyl group in the substance are not equivalent. The isomers of the cobalt(III) complex with the asymmetric tetradentate SS-EDDIV ligand were prepared and separated; their characteristics are given. The absolute configuration of two of the five theoretically feasible isomers was determined based on their electronic absorption spectra and circular dichroism data.

scholarly journals Structural Investigations of C-Nitrosobenzenes. Part 3.1 Solid-state and Solution 13C NMR Studies, and Crystal Structure of E-(4-CIC6H4NO)2

1999 ◽  
Vol 23 (3) ◽  
pp. 202-203
Author(s):  
Daniel A. Fletcher ◽  
Brian G. Gowenlock ◽  
Keith G. Orrell ◽  
David C. Apperley ◽  
Michael B. Hursthouse ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
13C Nmr ◽  
Nmr Studies ◽  
Structural Investigations ◽  
Nmr Data ◽  
C Nmr

Solid-state and solution 13C NMR data for the monomers and dimers of 3- and 4-substituted nitrosobenzenes, and the crystal structure of E-(4-CIC6H4NO)2 are reported.

The dependence of racemization in peptide synthesis on the relative configuration of amino acids

1978 ◽  
Vol 19 (30) ◽  
pp. 2711-2712 ◽  
Author(s):  
Anatol Arendt ◽  
Aleksander M. Kołodziejczyk ◽  
Teresa Sołowska
Keyword(s):  
Amino Acids ◽  
Peptide Synthesis ◽  
Relative Configuration

A 19F, 119Sn nuclear magnetic resonance and 119Sn Mössbauer study of the SnF2–MF–H2O system

1984 ◽  
Vol 62 (3) ◽  
pp. 591-595 ◽  
Author(s):  
Thomas Birchall ◽  
Georges Dénès
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Spectroscopic Data ◽  
Dominant Species ◽  
Mössbauer Study ◽  
Frozen Solution ◽  
Nmr Data ◽  
Mössbauer Measurements ◽  
Mössbauer Parameters ◽  
High Concentrations ◽  
Frozen Solutions

19F and 119Sn nmr spectroscopy has been used to study the SnF2–MF–H2O (M = Li+, Na+, K+, Rb+, Cs+, and [NH4]+) system. The nmr data have been supplemented by frozen solution 119Sn Mössbauer measurements. The evidence suggests that the dominant species in the SnF2–H2O system is a hydrated stannous fluoride, probably SnF2•H2O having Mössbauer parameters of δ = 3.46 mm s−1 and Δ = 1.70 mm s−1. When F− is added to these solutions rapid F− exchange occurs with the hydrated SnF2 and the dominant species becomes [SnF3]−. The 119Sn nmr chemical shift of [SnF3]− is ~ −700 ppm from (CH3)4Sn. The 119Sn Mössbauer parameters for frozen solutions of [SnF3]− are δ = ~ 3.1 mm s−1 Δ = 1.9 mm s−1. These spectroscopic data are cation dependent. We could find no strong evidence for high concentrations of [Sn2F5]− in any of these solutions.

13C-NMR Sequence Analysis. XVIII. Tacticity of Poly(D,L-β-amino Acids)

1980 ◽  
Vol 14 (7) ◽  
pp. 977-990 ◽  
Author(s):  
Hans R. Kricheldorf ◽  
R. Mülhaupt ◽  
William E. Hull
Keyword(s):  
Amino Acids ◽  
Sequence Analysis ◽  
13C Nmr

13C NMR shielding tensors of carboxyl carbon in amino acids calculated by ONIOM method

2004 ◽  
Vol 399 (1-3) ◽  
pp. 172-176 ◽  
Author(s):  
Anmin Zheng ◽  
Minghui Yang ◽  
Yong Yue ◽  
Chaohui Ye ◽  
Feng Deng
Keyword(s):  
Amino Acids ◽  
13C Nmr ◽  
Shielding Tensors ◽  
Oniom Method ◽  
Carboxyl Carbon

A Pyoverdin from the Antarctica Strain 51W of Pseudomonas fluorescens

1999 ◽  
Vol 54 (3-4) ◽  
pp. 156-162 ◽  
Author(s):  
Jessica Voss ◽  
Kambiz Taraz ◽  
Herbert Budzikiewicz
Keyword(s):  
Amino Acids ◽  
Pseudomonas Fluorescens ◽  
Binding Sites ◽  
Chemical Shifts ◽  
Chemical Degradation ◽  
Spectroscopic Methods ◽  
Extreme Conditions ◽  
Structural Elements ◽  
Nmr Data ◽  
Schirmacher Oasis

From the strain 51W of Pseudomonas fluorescens living under extreme conditions at the Schirmacher Oasis (Antarctica) a pyoverdin was obtained. Its structure was elucidated by chemical degradation and spectroscopic methods. The NMR data of the pyoverdin and of its Ga(III) complex were compared. Appreciable influences of the metal on the chemical shifts of the atoms at its binding sites were observed. Thus the structural elements involved in the complexation can be identified and coinciding signals of amino acids occurring more than once in the peptide chain can be separated.

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