关键词: 点击化学, 复式环糊精, 手性固定相, 手性识别, 高效液相色谱

A novel tandem-inverted triazole-bridged duplex “native-acetylated” hybrid cyclodextrin (CD) stationary phase material (ANCDCSP) was constructed via a surface-up ‘click’ approach. Mono-6-azido-CD was first immobilized onto the pre-dried silica surfaces as the down layer via ether linkage on C2 position, followed by acetylation of the cyclodextrin –OH groups with acetic anhydride. The top layer was fabricated by anchoring the synthesized alkyne functionalized CD onto the down CD layer via organic soluble Cu(I) catalytic 1,3-dipolar cycloaddition reaction (click chemistry) reported by us previously. The obtained crude material was purified by washing with N,N-dimethylformamide (DMF) twice followed by Soxlet extraction with acetone to afford the novel triazole-bridged duplex hybrid CD CSP and its structure was characterized via Fourier Transfer Infrared Spectroscopy (FTIR), thermogravimetric analysis (TG) and elemental analysis (EA). The hybrid bilayer ANCDCSP can provide multiple interaction sites such as H-bonding (OH, C=O, NH), steric effects, dipole-dipole and synergistic effect inclusion complexation, which helps to broaden the CSP’s enantioselectivity profile and enhance the enantioselectivity to some specific analytes. The CSP was applied for HPLC enantioseparation of various chiral compounds such as dansyl amino acids, carboxylic aryl acids, isoxazolines and some other racemates under reversed-phase separation mode using methanol/water and methanol/buffer as the mobile phases. Most of the dansyl amino acids and carboxylic aryl acids as well as bendroflumethiazide can be baseline separated. The isoxazolines, phenyl oxirane, atropine, DL-norleucine methyl ester and benfluorex were partially separated. The resolutions of Dns-Phe, DL-3PhLacA and Bendroflumethiazide reached 5.3, 4.1 and 4.1, respectively. The separation ability of the current CSP is superior to that of the duplex native cyclodextrins chiral stationary phase (DCDCSP) prepared by our group previously, especially in separation of dansyl amino acids, isoxazolines and bendroflumethiazide. Besides, the current CD CSP affords relatively good stability, which was verified by the satisfied reproducibility after 150 runs with or without buffer (pH 4.10).

Key words: click chemistry, bilayer cyclodextrin, chiral stationary phase, enantiorecognition, HPLC ester