title: Unusually high enantioselectivity in high-performance liquid chromatography using cellulose tris(4-methylbenzoate) as a chiral stationary phase.
abstract: The cellulose tris(4-methylbenzoate) chiral stationary phase (CSP) (commercially known as Chiralcel OJ-H) exhibited an extremely high enantioselectivity when used in the HPLC resolution of N-thiocarbamoyl-3-(4'-prenyloxy)-phenyl-5-phenyl-4,5-dihydro-(1H) pyrazole (Compound 1), in both normal-phase and polar organic conditions. Using n-hexane-ethanol (80:20, v/v) as a mobile phase, an enantioseparation factor value of 138.5 was found. In order to modulate the elution time of the longer retained enantiomer, a simple HPLC procedure was developed. The optimized analytical protocol was based on the stopped flow technique and did not involve any change in mobile phase composition. The stronger interaction energy of the (S) enantiomer compared to that of the (R) enantiomer was mainly attributed to the formation of a hydrogen bonding between the amino group of the thiocarbamoyl moiety and the carbonyl oxygen of the CSP.
authors.affiliation: Istituto Superiore di Sanità, Dipartimento del Farmaco, Rome, Italy. rcirilli@iss.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Cirilli
authors.forename: Stefano
authors.initials: S
authors.lastname: Alcaro
authors.forename: Rossella
authors.initials: R
authors.lastname: Fioravanti
authors.forename: Daniela
authors.initials: D
authors.lastname: Secci
authors.forename: Stefano
authors.initials: S
authors.lastname: Fiore
authors.forename: Francesco
authors.initials: F
authors.lastname: La Torre
authors.forename: Francesco
authors.initials: F
authors.lastname: Ortuso
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods*; D013237:Stereoisomerism
chemical_list: C070231:Chiracel OJ; D002482:Cellulose