Development of Practical Resolution System

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1. Phenylcarbamate derivatives of cellulose and amylose having chloro or fluoro and methyl groups on the phenyl moieties were synthesized, and their chiral recognition abilities were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). The cellulose derivatives with halogen and methyl groups at the meta and para positions showed higher resolving power than the ortho- and meta-disubstituted derivative. On the other hand, the ortho-substituted derivative of amylose showed slightly lower chiral recognition than those of the meta- and para-disubstituted derivatives.2. We have found that cellulose tris (5-fluoro-2-methylphenylcarbamate) is soluble in chloroform and is capable of discriminating enantiomers of 1,1'-bi-2-naphthol in ^1H and ^<13>C NMR with large chemical shift changes of the enantiomers as well as in HPLC accompanying the large separation factors (alpha>3). The molecular modeling on the basis of the chromatography and NMR data reveals the chiral discrimination rationale for a cellulose phenylcarbamate derivative. We also carried out force-field calculations of the interaction energies between tris (phenylcarbamate) or tris (3,5-dimethylphenylcarbamate) of cellulose and trans-stilbene oxide using Quanta/Charmm or Cerius2. (MSI). The calculation results were well consistent with the HPLC results.3. Phenylcarbamate-based CSPs have been prepared by coating the phenylcarbamates on silica gel. However, solvents such as THF can not be used as the eluents, because the derivatives are dissolved or swollen in the solvents. To improve this defect, amylose was bonded to silica gel at the reducing terminal residue. Amylose with desired chain length was prepared by polymerization of alpha-D-glucose 1-phosphate dipotassium salt with functionalized maltooligosaccharides using a phosphorylase from potato. The CSP showed excellent resolving ability and high durability against solvents such as THF.