Quaternized chitin used as chiral stationary phase for HPLC and the high enantioseparation of 1,2,3,4-tetrahydro-1-naphthalenamine racemates

Abstract

Quaternized chitin (QC) with different degrees of substitution (DSs) and molecular weight (Mw) were homogeneously synthesized. Eight novel chiral stationary phases (CSPs) for HPLC were prepared by coating the QC on 3-aminopropyl silica gel, which were firstly used to separate 1,2,3,4-tetrahydro-1-naphthalenamine (THNA) racemates. Enantioseparation capability of the CSPs was evaluated and the influence factors including DS and Mw of QCs were explored respectively. The results demonstrated that the successful separation of THNA enantiomers was obtained by all the new CSPs of the chitin derivatives. Resolution (Rs) increased from 1.12 to 1.58 with the increase of DS of QC from 0.40 to 0.62, while the Rs decreased with the reduction of Mw of the products from 2.8 × 105 to 9.7 × 104. The maximum Rs is 2.29. A simple pathway for the fabrication of novel CSPs of cationic chitin derivatives is developed, which has potential application for the separation of THAN racemates.