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Phenylalanine‐Derived Imidazolines Bearing Heteroaromatic Pendants: Synthesis, Characterization, and Application in the Asymmetric Henry Reaction
Author(s) -
Tydlitát Jiří,
Bureš Filip,
Růžičková Zdeňka
Publication year - 2015
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201500128
Subject(s) - chemistry , structural isomer , imidazoline receptor , enantiomer , diamine , hydrolysis , catalysis , enantiomeric excess , phenylalanine , stereochemistry , organic chemistry , enantioselective synthesis , amino acid , medicine , biochemistry
Starting from L ‐phenylalanine, (2 S )‐3‐phenylpropane‐1,2‐diamine has been prepared and used as building block for the construction of the imidazoline ring. Four new optically pure NH‐imidazolines bearing different six‐membered heteroaromatic substituents on the C(2) position have been prepared and subsequently N‐modified. N‐Substitution afforded two regioisomers that were separated. Some of them proved to be instable and hydrolyzed to diamides. The molecular structures of NH‐imidazolines, both N‐substituted regioisomers, as well as diamides, were unambiguously confirmed by X‐ray‐analysis and NMR spectra. The successfully prepared imidazolines, as well as diamides, were applied as catalysts in a Cu(II)‐catalyzed Henry reaction achieving 26–98% chemical yields and enantiomeric excesses of 3–42%.