Homogeneous synthesis of partially substituted cellulose phenylcarbamates aiming at chiral recognition

Homogeneous carbanilation of cellulose with nine kinds of substituted phenyl isocyanates, in which the substituents were varied from electron‐donating to electron‐withdrawing groups, was carried out in 1‐allyl‐3‐methylimidazolium chloride ( AmimCl ) without any catalyst. The degree of substitution ( DS ) of cellulose phenylcarbamates in a range from 0 to 3 was readily controlled by altering reaction temperature, reaction time and molar ratio of phenyl isocyanate/anhydroglucose unit. Furthermore, the electronic effect of the substituents on the aromatic ring had a prominent impact on the reactivity of phenyl isocyanates. The phenyl isocyanates with stronger electron‐withdrawing substituents exhibited a higher reactivity. A plot of DS and Hammett substituent constants exhibited linearity with a positive slope. Subsequently, four kinds of partially substituted cellulose phenylcarbamates with DS of 2.0 were synthesized successfully in AmimCl , and then employed as coated‐type chiral stationary phases ( CSPs ) for high‐performance liquid chromatography. The enantioseparation results demonstrated that these CSPs exhibited high chiral recognition abilities for some racemates. The substituents on the phenyl moieties had a considerable effect on the chiral recognition ability of cellulose phenylcarbamate‐based CSPs . © 2015 Society of Chemical Industry