Conformational analysis of a cyclopropane analogue of phenylalanine with two geminal phenyl substituents.
Quantum mechanical methods have been used to investigate the intrinsic conformational preferences of 1-amino-2,2-diphenylcyclopropanecarboxylic acid (c(3)Dip), a cyclopropane analogue of phenylalanine bearing two phenyl substituents on the same beta-carbon. Geometries, energies, and frequencies were calculated on the N-acetyl-N'-methylamide derivative at the HF and B3LYP levels using the 6-31G(d), 6-311G(d), and 6-31+G(d,p) basis sets. Four minimum energy conformations were characterized: axial C(7), equatorial C(7), right-handed helix, and polyproline II. Analysis of the whole results, which are fully consistent with available experimental data, indicates that c(3)Dip tends to promote gamma-turn conformations.
Casanovas
Jordi
J
Departament de Química, Escola Politècnica Superior, Universitat de Lleida, c/Jaume II N 69, 25001 Lleida, Spain. carlos.aleman@upc.edu
Jiménez
Ana I
AI
Cativiela
Carlos
C
Pérez
Juan J
JJ
Aleman
Carlos
C
D003521:Cyclopropanes / Q000737:chemistry*; D008968:Molecular Conformation; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D011789:Quantum Theory; D013816:Thermodynamics
C481928:(2S,3S)-1-amino-2,3-diphenylcyclopropanecarboxylic acid; D003521:Cyclopropanes; D010649:Phenylalanine