177171-07-2Relevant articles and documents
Synthesis and hydrogen bonding capabilities of biphenyl-based amino acids designed to nucleate β-sheet structure
Nesloney, Carey L.,Kelly, Jeffery W.
, p. 3127 - 3137 (2007/10/03)
The syntheses of 3′-(aminoethyl)-2-biphenylpropionic acid (1) and 2-amino-3′-biphenylcarboxylic acid (2) are described. These residues were designed to nucleate β-sheet structure in aqueous solution when incorporated into small, amphiphilic peptides in place of the backbone of the i + 1 and i + 2 residues of the β-turn. N-Benzyl-3′-(2-(benzylamido)ethyl)-2-biphenylpropamide (3) and N-benzyl-(2-benzylamido)-3′-biphenylamide (4) were synthesized and studied as model compounds to investigate the hydrogen-bonding capabilities of residues 1 and 2, respectively. The X-ray crystal structure of 3 indicates that a 13-membered intramolecular hydrogen-bonded ring is formed, while the remaining amide proton and carbonyl are involved in intermolecular hydrogen bonding. Infrared and variable-temperature NMR experiments indicate that, in solution (CH2Cl2), 3 exists as an equilibrium mixture of the 13- and the 15-membered intramolecularly hydrogen-bonded conformers with the 15-membered ring conformer being favored. Amide 4 was shown to exist in solution (CH2Cl2) as an equilibrium mixture of the 11-membered intramolecular hydrogen-bonded ring and a nonbonded conformation. No contribution from the 9-membered hydrogen-bonded ring conformation was observed. The X-ray crystal structure of 4 indicated the absence of intramolecular hydrogen bonding in the solid state.
