Rational Design of Bioorganometallic Foldamers: A Potential Model for Parallel β‐Helical Peptides

Abstract

Twists and turns: A series of alanine conjugates of ferrocene amino acid (Fca) were prepared based on the idea that an alternating sequence of a natural α‐amino acid and a turn‐inducing molecule may result in the formation of a robust model foldamer for β‐helical peptides. Right‐ and left‐handed pseudo‐β‐helical Fca–alanine foldamers were obtained, and their structures were studied in solution and the solid state.

Designer Peptides: Attempt to Control Peptide Structure by Exploiting Ferrocene as a Scaffold

“…The first peptide conjugate of 14, shown in Figure 11, was reported by Metzler-Nolte. [29] Contrasting Fcdicarboxylic acid conjugates, the structure of Boc--AlaFca--Ala--Ala-OMe (35) (Figure 11) displays a 9-and 11-membered H-bonded ring, established by interactions involving the proximal Fc-NH and the OC-Ala groups. It is interesting to note that the H-bonding interactions and therefore the axial chirality element of the Fc core are present also at elevated temperatures and in the presence of methanol.…”

“…Redrawn from ref. [35] Will it be possible to exploit this design principle for other Fca helicates involving other amino acids or even peptides resulting in more complex helicates? Such systems are of fundamental interest but can also serve as models for extended β-sheets and may serve as a more convenient model to study the interactions between such models and small molecules.…”

“…Fca conjugates with the general formula Boc-[Fca-Ala] n -OMe (n = 1-4) exhibit a β-helical-like structure in solution and in the solid state. [35] The solid-state structures of a series of molecules of this family were examined and exhibit molecular helicity as shown in Figure 18 for Boc-[Fca--Ala] 3 -OMe (47) and Boc-[Fca--Ala] 3 -OMe (48). The helicates of -Ala and -Ala are enantiomers and display opposite helicity that is preserved in solution and at elevated temperatures.…”

Metal–Carbon Bonds in Biopolymer Conjugates: Bioorganometallic Nucleic Acid Chemistry

“…9 Peptide-based systems containing ferrocene 10 as well as other metallocenes 11 have been studied fairly extensively, with oligoferrocenyl peptides displaying interesting multielectron reaction properties. 12 This review focuses on bioorganometallic nucleic acid chemistry with a particular focus on different approaches used to synthesize such modified or artificial nucleic acids. As such, it complements recent reviews that have included discussions of various applications of bioorganometallic systems.…”

Development and Analysis of Functionalized Poly(Lactide- Co-Glycolide)Polymer for Drug Delivery

“…Unreacted TFA was removed by addition of DCM to form positive azeotrope, which could be removed at a temperature much lower than the boiling point of TFA ( 72.4°C) [24]. The process of addition of DCM was repeated multiple times for the thorough removal of TFA from the reaction mixture.…”