3,5-DIMETHYLPHENYLCARBAMATES OF CELLULOSE AND AMYLOSE REGIOSELECTIVELY BONDED TO SILICA-GEL AS CHIRAL STATIONARY PHASES FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

3,5-Dimethylphenylcarbamates of amylose (ADMPC) (1) and cellulose (CDM PC) (2) chemically bonded to 3-aminopropylsilica gel were prepared wit h 4,4'-diphenylmethane diisocyanate as a spacer and their optical reso lution abilities were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). To investigate the inf luence of the position of the glucose unit in immobilization on chiral recognition, the polysaccharide derivatives were regioselectively bon ded to the silica surface. ADMPC regioselectively bonded at the B-posi tion to silica gel possesses a higher optical resolving power than tha t bonded at the 2- or 3-position. The chiral recognition ability of th e former CSP was almost comparable to that of ADMPC coated an silica g el. For CDMPC, the position of glucose in immobilization on silica gel hardly affected the chiral recognition. The enantioselectivities of t hese CSPs were also influenced by the amount of the diisocyanate used for immobilization. These chemically bonded-type CSPs were able to be used with eluents such as CHCl3, in which the polysaccharide derivativ es are soluble or swollen. A few racemates which were not or poorly se parated on the coated-type CSP were more efficiently resolved on the c hemically bonded-type CSP using CHCl3, as a component of the mobile ph ase.