Conformational analysis of helical aminoisobutyric acid (Aib) oligomers bearing C-terminal ester Schellman motifs.

Content Provider	Semantic Scholar
Author	Pike, Sarah J. Raftery, James Webb, Simon J. Clayden, Jonathan
Copyright Year	2014
Abstract	The effect of Schellman motifs on the adoption of stable 310 helical conformations in a series of aminoisobutyric (Aib) oligomers has been studied in the solid state and solution. The destabilising effect of the Schellman motif (a local inversion of helical screw-sense due to a C-terminal ester residue) was quantified in the solid state using X-ray crystallography through analysis of the torsion angles and their deviation from those observed in an ideal 310 helix. Investigation of the intramolecular hydrogen-bonding interactions in the solid state led to the identification of a fully extended C5 conformation in one oligomer, which is a novel folding motif for Aib oligomers. The effect of ester groups with differing steric demands on intermolecular hydrogen-bonding contacts in the solid state was also ascertained. In solution, the adoption of a 310 conformation in Aib oligomers appeared to be more finely tuned, depending on a number of factors, including chain length and the steric demands of the C-terminal destabilising Schellman motif.
File Format	PDF HTM / HTML
DOI	10.1039/c4ob00268g
Alternate Webpage(s)	http://www.rsc.org/suppdata/ob/c4/c4ob00268g/c4ob00268g1.pdf
PubMed reference number	24831537
Alternate Webpage(s)	https://doi.org/10.1039/c4ob00268g
Journal	Medline
Volume Number	12
Issue Number	24
Journal	Organic & biomolecular chemistry
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article