title: Induced axial chirality in the biphenyl core of the proatropoisomeric, C alpha-tetrasubstituted alpha-amino acid residue Bip in peptides.
abstract: An induced axial chirality in the biphenyl core of the 2',1':1,2;1'',2'':3,4-dibenzcyclohepta-1,3-diene-6-amino-6-carboxylic acid (Bip) residue, a conformationally labile, atropoisomeric, C(alpha)-tetrasubstituted alpha-amino acid, was observed by CD and (1)H NMR spectroscopic techniques in the linear dipeptides Boc-Bip-Xaa*-OMe where Boc=tert-butoxycarbonyl, OMe=methoxy, and Xaa*=D- and/or L-Ala, -Val, -Leu, -Phe, -(alphaMe)Val and -(alphaMe)Leu. Chiral induction was significantly lower in the isomeric dipeptides Boc-Xaa*-Bip-OMe, with the Xaa* residue located at the N-terminus of Bip, as well as in the cyclic dipeptide cyclo-[Bip-L-Ala]. The results obtained in solution were confirmed by X-ray diffraction analysis of a crystalline sample of Boc-(R)-Bip-D-Ala-OMe.
authors: SIRCOB, UMR CNRS 8086, University of Versailles, 78035 Versailles, France.
authors: Jean-Paul
authors: JP
authors: Mazaleyrat
authors: Karen
authors: K
authors: Wright
authors: Anne
authors: A
authors: Gaucher
authors: Nathalie
authors: N
authors: Toulemonde
authors: Laurence
authors: L
authors: Dutot
authors: Michel
authors: M
authors: Wakselman
authors: Quirinus B
authors: QB
authors: Broxterman
authors: Bernard
authors: B
authors: Kaptein
authors: Simona
authors: S
authors: Oancea
authors: Cristina
authors: C
authors: Peggion
authors: Marco
authors: M
authors: Crisma
authors: Fernando
authors: F
authors: Formaggio
authors: Claudio
authors: C
authors: Toniolo
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D010455:Peptides