Division of Organic Chemistry, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411-008, India.
Chemistry. 2011 Nov 11;17(46):12946-54. doi: 10.1002/chem.201101855. Epub 2011 Oct 20.
The synthesis of homochiral homo-oligomers of cis- and trans-3-aminotetrahydrofuran-2-carboxylic acids (parent cis- and trans-furanoid-β-amino acids, referred to as "cis-/trans-FAA") has been carried out to understand their secondary structures and their dependence on the ring heteroatom. The oligomers of two diastereomers have been shown to have a distinct left-handed helicity. The cis-FAA homo-oligomers show a 14-helix structure, in contrast to the homo-oligomers of cis-ACPC, which adopt a sheet like structure. The trans-FAA homo-oligomers were found to adopt a 12-helix structure, the same trend found in trans-ACPC homo-oligomers. With the help of ab initio calculations, the structural features of cis-ACPC and cis-FAA hexamers were compared. We believe that the more compact packing of the cis-FAA hexapeptide should be due to a more favorable interaction between the ring and the backbone amide hydrogen.
已合成了顺式和反式 3-氨基四氢呋喃-2-羧酸（母体顺式和反式呋喃型-β-氨基酸，简称“顺式/反式-FAA”）的同手性同寡聚物，以了解它们的二级结构及其对环杂原子的依赖性。两种非对映异构体的寡聚物表现出明显的左手螺旋性。顺式-FAA 同寡聚物呈现 14-螺旋结构，与顺式-ACPC 的同寡聚物不同，顺式-ACPC 采用片状结构。反式-FAA 同寡聚物被发现采用 12-螺旋结构，与反式-ACPC 同寡聚物相同。借助从头算计算，比较了顺式-ACPC 和顺式-FAA 六聚体的结构特征。我们相信，顺式-FAA 六肽更紧凑的堆积应该是由于环和主链酰胺氢之间更有利的相互作用。
