title: Enantioselective recognitions of chiral molecular tweezers containing imidazoliums for amino acids.
abstract: Two kinds of novel chiral molecular tweezers containing imidazoliums were synthesized from L-alanine, L-phenylalanine, and L-glutamic acid. They are constructed by the chiral imidazolium pincers and two different spacers which are 1,3-bis (bromomethyl)benzene and 2,6-bis(bromomethyl)pyridine, respectively. The enantioselective recognition of L- and D-amino acid derivatives by these molecular tweezers was investigated by UV spectroscopic titration experiments and good enantioselectivities were obtained, which are highly sensitive to whether the spacer has the binding site and the pincers has the other aromatic rings besides imidazolium ring. The host molecular 3b.2PF6- showed remarkable enantioselectivity for N-Boc protected histidine methyl ester, affording K(L)/K(D) of 5.10.
authors.affiliation: Department of Chemistry, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Su
authors.forename: Kui
authors.initials: K
authors.lastname: Luo
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Xiang
authors.forename: Jingbo
authors.initials: J
authors.lastname: Lan
authors.forename: Rugang
authors.initials: R
authors.lastname: Xie
mesh_terms: D000688:Amylose / Q000031:analogs & derivatives / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry; D018698:Glutamic Acid / Q000737:chemistry*; D006639:Histidine / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D010649:Phenylalanine / Q000737:chemistry*; D048448:Phenylcarbamates / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D048448:Phenylcarbamates; D011725:Pyridines; C079151:cellulose trisphenylcarbamate; C080033:Chiralpak AD; D018698:Glutamic Acid; D010649:Phenylalanine; D006639:Histidine; D002482:Cellulose; D000688:Amylose; C053861:histidine methyl ester