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Design and Synthesis of Diastereomeric β 3 ‐Peptides from ( R , R )/( S , S )‐APyC and ( R )/( S )‐β 3 ‐Caa: Determination of Enantiomeric Handedness
Author(s) -
Sharma Gangavaram V. M.,
Ravindranath Hajari,
Bhaskar Akkala,
Sirisha Katukuri,
Ramakrishna Kallaganti V. S.,
Sarma Akella V. S.
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201501053
Subject(s) - chemistry , diastereomer , enantiomer , stereochemistry , amide , amino acid , monomer , proton nmr , oxygen atom , molecule , organic chemistry , biochemistry , polymer
We have previously reported enantiomeric α/β‐ and β‐peptides derived from aminopyrancarboxylic acids (APyCs). We now report the synthesis of diastereomeric β‐peptides synthesized from alternating ( R , R )/( S , S )‐APyCs and C ‐linked carbo β 3 ‐amino acids [( R )/( S )‐β 3 ‐Caas] and their conformational analysis. Extensive studies of these peptides revealed the presence of enantiomeric helical structures, that is, left‐ and right‐handed 12/10‐helices, that are well stabilized by five‐membered electrostatic interactions between the pyran oxygen atom and the succeding amide proton. The study thus reveals, irrespective of the nature of the peptides, that the APyC monomers influence on the outcome of the helical handedness, as established by NMR, CD and molecular dynamics (MD) analyses.