Design and Synthesis of Diastereomeric β³-Peptides from ( R, R)/( S, S)-APyC and ( R)/( S)-β³-Caa: Determination of Enantiomeric Handedness.

Sharma, Gangavaram V. M.; Ravindranath, Hajari; Bhaskar, Akkala; Sirisha, Katukuri; Ramakrishna, Kallaganti V. S.; Sarma, Akella V. S.

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 β3-amino acids [( R)/( S)-β3-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.

ENANTIOMERS; PEPTIDES; CARBOXYLIC acids; DIASTEREOISOMERISM; AMIDES

European Journal of Organic Chemistry, 2016, Vol 2016, Issue 1, p168

1434-193X

Academic Journal

10.1002/ejoc.201501053