Enantiomer separation on novel cellulose derivatives bearing regioselective phenylcarbamate groups

Four novel regioselectively carbamoylated cellulose derivatives with two types of substituents, one being a 3-chloro-4-methylphenylcarhamate group and the other being a phenylcarbamate, a 3,5-dichiorophenylcarbamate or a 4-methylphenylcarbamate group, at the 2-, 3-positions and 6-position were synthesized and utilized as chiral stationary phases in high-performance liquid chromatography. The obtained derivatives exhibited characteristic chiral recognition abilities which were significantly affected by the nature and arrangement of the groups at the 2-, 3-positions and 6-position. Compared with cellulose tris(3-chloro-4-methylphenylcarbamate) and Chiralcel OD columns, several racemates were better resolved on these new phases. With all six racemates resolved on cellulose 2,3-bis(4-methylphenyl carbam ate)-6-(3-chloro4-methylphenylcarbamate), it appears to be a potential useful chiral stationary phase in the future. Also, the influence of mobile phase on chiral recognition was investigated. Better resolutions were generally obtained with decreased amount of 2-propanol with a mixture of hexane/2-propanol as the mobile phase. Moreover, when ethanol was used instead of 2-propanol as the mobile phase modifier, poorer enantioseparations were often achieved.

Automated summary

Four novel regioselectively carbamoylated cellulose derivatives were synthesized and utilized as chiral stationary phases in high-performance liquid chromatography. The chiral recognition abilities of these derivatives were significantly affected by the nature and arrangement of the groups at different positions, leading to improved resolution of racemates. Investigating the influence of mobile phase on chiral recognition revealed that better resolutions were generally obtained with decreased amount of 2-propanol and poorer enantioseparations were often achieved when ethanol was used instead of 2-propanol as the mobile phase modifier.