Crystal Structures of Dipeptides Derived from the β-Amino Acids (1R,2S)-2-Aminocyclopentanecarboxylic Acid and (1S,2R,3S)-2-Amino-3-methylcyclopentanecarboxylic Acid
作者:Elin Abraham、Stephen G. Davies、Paul M. Roberts、Amber L. Thompson、James E. Thomson
DOI:10.1007/s10870-011-0164-x
日期:2011.11
Crystals of the dimeric β-peptides 13 and 20, derived from (1R,2S)-2-aminocyclopentanecarboxylic acid and (1S,2R,3S)-2-amino-3-methylcyclopentanecarboxylic acid, respectively, were synthesised and studied by X-ray diffraction in order to establish their solid state secondary structural characteristics. Compound 13 crystallises in the monoclinic space group P 2 1 with cell parameters of a = 5.2682(1) Å, b = 9.1211(2) Å, c = 22.4467(6) Å, β = 91.3855(9)°, V = 1078.29(4) Å3 and Z = 2. Compound 20 crystallizes in the orthorhombic space group P 2 1 2 1 2 1 with cell parameters of a = 5.0968(1) Å, b = 11.5546(2) Å, c = 43.5414(8) Å, V = 2564.22(8) Å3 and Z = 4. In both cases adjacent molecules are linked by a series of N–H···O=C hydrogen bonds to form β-sheet like structures. The structures of two dipeptides derived from the β-amino acids (1R,2S)-2-aminocyclopentanecarboxylic acid and (1S,2R,3S)-2-amino-3-methylcyclopentanecarboxylic acid have been analysed by X-ray diffraction.
为了确定其固态二级结构特征,我们合成了分别来自(1R,2S)-2-氨基环戊烷羧酸和(1S,2R,3S)-2-氨基-3-甲基环戊烷羧酸的二聚 β 肽 13 和 20 的晶体,并对其进行了 X 射线衍射研究。化合物 13 在单斜空间群 P 2 1 中结晶,晶胞参数为 a = 5.2682(1) Å,b = 9.1211(2) Å,c = 22.4467(6) Å,β = 91.3855(9)°,V = 1078.29(4) Å3,Z = 2。化合物 20 在正交空间群 P 2 1 2 1 2 1 中结晶,晶胞参数为 a = 5.0968(1) Å,b = 11.5546(2) Å,c = 43.在这两种情况下,相邻分子通过一系列 N-H-O=C 氢键相连,形成类似 β 片状结构。X 射线衍射分析了从 β-氨基酸 (1R,2S)-2- 氨基环戊烷羧酸和 (1S,2R,3S)-2-氨基-3-甲基环戊烷羧酸衍生的两种二肽的结构。