Unusually high enantioselectivity in high-performance liquid chromatography using cellulose tris(4-methylbenzoate) as a chiral stationary phase.
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.
Cirilli
Roberto
R
Istituto Superiore di Sanità, Dipartimento del Farmaco, Rome, Italy. rcirilli@iss.it
Alcaro
Stefano
S
Fioravanti
Rossella
R
Secci
Daniela
D
Fiore
Stefano
S
La Torre
Francesco
F
Ortuso
Francesco
F
D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods*; D013237:Stereoisomerism
C070231:Chiracel OJ; D002482:Cellulose