Synthesis of Some 2,2′:6′,2″-Terpyridines Disubstituted in Positions 6 and 6″ with Head-to-Tail Oriented Amino Acids and Dipeptides: A Simple Entry to a Reversible Inducer of Folding in Amino Acid Sequences
✍ Scribed by Rita Annunziata; Maurizio Benaglia; Alessandra Puglisi; Laura Raimondi; Franco Cozzi
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 217 KB
- Volume
- 2008
- Category
- Article
- ISSN
- 1434-193X
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✦ Synopsis
Abstract
The 2,2′:6′,2″‐terpyridine scaffold has been identified as a conformationally discrete structural element potentially capable of inducing reversible folding in substituents, attached through suitable spacers to its 6,6″‐positions, by metal complexation/decomplexation or by protonation/deprotonation. The synthesis of some terpyridine–amino acids and terpyridine–dipeptide conjugates is described. The assembly of these conjugates has been achieved by connecting NH~2~‐ and CO~2~H‐protected glycine, alanine, and valine residues or antiparallel oriented AlaGly/GlyAla chains to the terpyridine scaffold through phenylacetylene spacers. Preliminary experiments showed that upon addition of Zn^2+^ to the amino acid substituted transoid terpyridine systems, folded cisoid complexes were formed. Also, bis(protonation) of the dipeptide‐substituted system resulted in the formation of a folded adduct. Reversibility of the folding process was shown by Zn^2+^ removal with triethylamine or deprotonation with aqueous ammonia. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)