title: A highly selective receptor for zwitterionic proline.
abstract: A chiral chromane receptor has been synthesized which mimics the oxyanion hole of the enzymes. In this receptor H-bonds and cation-π interactions team up to generate an apolar host-guest complex with zwitterionic proline. This complex allows the extraction of only proline to a chloroform phase, while no other natural amino acids are extracted. Due to the chiral nature of the receptor, enantioselective extraction from the aqueous proline solution to a chloroform phase takes place. L-Proline provided an easy method to resolve the receptor racemic mixture, while anisotropic effects, NOE and CD studies revealed the absolute configuration of the receptor. Modelling studies also support the proposed structures. The presence of an oxyanion-hole motif in this structure was corroborated by X-ray diffraction studies.
authors.affiliation: Organic Chemistry Department, Plaza de los Caidos 1-5, University of Salamanca, 37008 Salamanca, Spain. romoran@usal.es.
authors.forename: Álvaro G
authors.initials: ÁG
authors.lastname: Temprano
authors.forename: Laura M
authors.initials: LM
authors.lastname: Monleón
authors.forename: Omayra H
authors.initials: OH
authors.lastname: Rubio
authors.forename: Luis Simón
authors.initials: LS
authors.lastname: Rubio
authors.forename: Asunción B
authors.initials: AB
authors.lastname: Pérez
authors.forename: Francisca
authors.initials: F
authors.lastname: Sanz
authors.forename: Joaquín R
authors.initials: JR
authors.lastname: Morán
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002725:Chloroform / Q000737:chemistry; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D010671:Phenylurea Compounds / Q000737:chemistry*; D011392:Proline / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: C000610517:6-tert-butyl-8-(3-(4-chlorophenyl)ureido)-2-phenyl-N-(pyridin-2-yl)chroman-2-carboxamide; D001578:Benzopyrans; D010671:Phenylurea Compounds; D002725:Chloroform; D011392:Proline