Enantioseparation Using Cellulose Tris(3,5-dimethylphenylcarbamate) as Chiral Stationary Phase for HPLC: Influence of Molecular Weight of Cellulose.
The cellulose oligomers with different degrees of polymerization (DP), 7, 11, 18, 24, 26, 40 and 52, were prepared by hydrolysis of microcrystalline cellulose with phosphoric acid. These oligomers including the starting microcrystalline cellulose (DP 124) were converted to tris(3,5-dimethylphenylcarbamate) (CDMPC) derivatives by the reaction with an excess of 3,5-dimethylphenyl isocyanate to be used as the chiral stationary phase (CSP) in high-performance liquid chromatography (HPLC). The structures of the CDMPC derivatives were investigated by infrared spectroscopy (IR), ¹H-NMR, circular dichroism (CD) and size exclusion chromatography (SEC), and the DPs of the derivatives estimated by SEC agreed with those estimated by ¹H-NMR. After coating the derivatives on silica gel, their chiral recognition abilities were evaluated using eight racemates under a normal phase condition with a hexane-2-propanol (99/1) mixture as an eluent. The chiral recognition abilities of 7- and 11-mers, particularly the former, were lower than those of the higher oligomers from DP 18 to 52, which had rather similar abilities to that of 124-mer, although the abilities depended on the racemates. DP 18 seems to be sufficient for CDMPC to exhibit chiral recognition similar to that of the CDMPC with larger DPs.
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. column_okd@yahoo.co.jp.
Yuji
Y
Okada
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. chiyo@chem.suzuka-ct.ac.jp.
Chiyo
C
Yamamoto
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. kamigait@apchem.nagoya-u.ac.jp.
Masami
M
Kamigaito
Polymer Materials Research Center, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. gaoyuan1@hrbeu.edu.cn.
Yuan
Y
Gao
Polymer Materials Research Center, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. shenjun@hrbeu.edu.cn.
Jun
J
Shen
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. okamoto@apchem.nagoya-u.ac.jp.|Polymer Materials Research Center, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. okamoto@apchem.nagoya-u.ac.jp.
Yoshio
Y
Okamoto
D002482:Cellulose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006868:Hydrolysis; D015394:Molecular Structure; D008970:Molecular Weight; D048448:Phenylcarbamates / Q000138:chemical synthesis* / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry*; D013237:Stereoisomerism
D048448:Phenylcarbamates; D010756:Phosphoric Acids; C065943:cellulose tris-3,5-dimethylphenyl-carbamate; D002482:Cellulose; C030242:phosphoric acid; C109691:microcrystalline cellulose
chiral separation; enantiomer; phenylcarbamate; polysaccharide