Document Detail


Differentiation of diastereomeric cyclic beta-amino acids by varying the neutral reagent in ion/molecule reactions studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.
MedLine Citation:
PMID:  18181235     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Stereochemical differentiation of diasteromeric pairs of cis- and trans-2-aminocyclohexane-, -2-amino-4-cyclohexene-, and -2-aminocyclopentanecarboxylic acids was investigated with host-guest complexes where tetraethyl resorcarene was the host molecule. Diastereoselectivity was evaluated by ion/molecule reactions and collision-induced dissociation with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS). The effect of varying the neutral reagent (n-propylamine, i-propylamine, diethylamine, and triethylamine) in ion/molecule reactions was evaluated. Both steric interactions and proton affinity of the neutral reagents influenced the reaction rates. High proton affinity of the neutral reagent apparently had a twofold effect. If the proton affinity of the neutral reagent was too high, the reaction tended to become too exothermic and part of the host-guest complex decomposed instead of transforming to a new host-guest complex, effecting a decrease in the reaction rate. The remaining portion of the host-guest complexes meanwhile reacted very fast with the neutral reagent due to high proton affinity causing an increase in the reaction rate. n-Propylamine and i-propylamine proved to be the best neutral reagents, providing clear diastereoselectivity for beta-amino acids in ion/molecule reactions. Interestingly, diastereoselectivity was better for flexible cyclohexane beta-amino acids (2 and 3) than for more rigid cyclopentane beta-amino acids (6 and 7). The results of ab initio and hybrid density functional theory calculations on the structures of the host-guest complexes of saturated beta-amino acids were in good agreement with the experimental results.
Authors:
Anna R M Hyyryläinen; Jaana M H Pakarinen; Pirjo Vainiotalo; Ferenc Fülöp
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Rapid communications in mass spectrometry : RCM     Volume:  22     ISSN:  0951-4198     ISO Abbreviation:  Rapid Commun. Mass Spectrom.     Publication Date:  2008  
Date Detail:
Created Date:  2008-01-17     Completed Date:  2008-04-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8802365     Medline TA:  Rapid Commun Mass Spectrom     Country:  England    
Other Details:
Languages:  eng     Pagination:  337-44     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2008 John Wiley & Sons, Ltd.
Affiliation:
Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
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MeSH Terms
Descriptor/Qualifier:
Amino Acids, Cyclic / analysis*,  chemistry*
Cyclotrons
Hydrogen-Ion Concentration
Indicators and Reagents / chemistry
Ions
Isomerism
Spectrometry, Mass, Electrospray Ionization / methods
Spectroscopy, Fourier Transform Infrared / methods*
Chemical
Reg. No./Substance:
0/Amino Acids, Cyclic; 0/Indicators and Reagents; 0/Ions

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