Carbamates of cellulose bonded on silica gel: Chiral discrimination ability as HPLC chiral stationary phases

Abstract

Four cellulose mixed 10-undecenoate/carbamate derivatives, simultaneously bearing 10-undecenoyl and variously substituted phenylaminocarbonyl groups, were chemically bonded on allylsilica gel. The study of the effect of these substitutions on the performance of the resulting chiral supports, and a comparison with the recently described 10-undecenoate/3,5-dimethylphenylcarbamate derivative, are presented. In this study heptane/2-propanol or heptane/chloroform mixtures were used as mobile phases. Chirality 10: 283-288, 1998. © 1998 KEY WORDS: chiral HPLC; cellulose carbamates; enantiomeric resolution; warfarin; flurbiprofen; lorazepam; oxazepam; pindolol; tertatolol; nicardipine Among the great number of chiral stationary phases (CSPs) for HPLC, those based on polysaccharides, especially cellulose and amylose, have broad application.1 The CSPs derived from tris(phenylcarbamate)derivatives of cellulose, readily prepared by reaction of microcrystalline cellulose with substituted phenylisocyanates and coated on ␥-aminopropylsilica gel, are the most investigated polysaccharide derived CSPs for HPLC.

Screening primary racemic amines for enantioseparation by derivatized polysaccharide and cyclofructan columns

“…Of these 1100 separations, it is striking to find that only seven primary amines were separated on bonded CSPs [20] . Herein, a screening procedure was established to evaluate the capabilities of the newly introduced bonded CSPs based on bonded derivatized polysaccharides [5] , [6] , [7] , [8] , [9] , [10] (trade name ChiralPak® with Ix codes). A recently introduced chiral column based on a bonded derivatized CF selector [13] , [14] , [15] , [16] , [17] , [18] , [19] (trade name Larihc®) was also evaluated.…”

“…Bonded polysaccharide based CSPs were later introduced, allowing for the use of a large variety of solvents in all chromatographic modes including super/subcritical mobile phases. Their enantiomeric separation capabilities showed similar but not identical capabilities when compared to their coated counterparts [9] , [10] .…”

Análise enantiosseletiva de fármacos: contribuições da cromatografia líquida de alta eficiência e eletroforese capilar

“…Isto limita a seleção da fase móvel a alguns solventes compatíveis, nos quais os derivados não são solú-veis. Na tentativa de desenvolver fases mais estáveis, alguns grupos de pesquisadores têm relatado a obtenção de fases estacionárias através da imobilização química do derivado ao suporte de sílica [53][54][55][56] . Outra direção no desenvolvimento de novas fases, é o uso de derivados de polissacarídeos modificados regiosseletivamente.…”

Techniques in Preparative Chiral Separations

“…Coated CSPs, consisting of a polysaccharide derivative, benzoate or aryl carbamate of cellulose or amylose, on a matrix of aminopropylsilanized silica gel, are also among the most extensively utilized CSPs [44][45][46][47][48][49]. This limitation can be overcome when the chiral selector is bonded to the chromatographic matrix [50][51][52][53][54][55][56][57]. CSPs whose chiral selectors are bonded to the chromatographic matrix (usually silica gel) can perform in a number of different conditions and compositions in the mobile phase.…”