Preparation of molecularly imprinted silica particles with amino functionality for chiral separation of (±)-naproxen

Herein is the synthesis and effective use of an S-naproxen (S-NP) enantioselective adsorbent material with amino functionality for the enantioseparation of a (±)-NP racemic mixture. To begin, the S-NP enantiomer of (3-aminopropyl)triethoxysilane was used to create an amide derivative (S-NP-Si-NH₂ ). In order to incorporate the S-NP enantiomeric species into the cross-linked material, the developed S-NP-Si-NH₂ derivative was combined with tetraethoxysilane (TEOS) and subjected base-catalyzed sol-gel condensation polymerization procedure. The S-NP is released from the cross-linked matrix by alkaline hydrolysis and subsequent acidification, creating an enantioselective gap filled with cationic ions that are compatible with the S-NP during recombination. With the use of elemental analysis, nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, it was verified that the performed chemical processes on the monomeric precursor and the resulting S-NP molecularly imprinted material (S-NP-Sil) were successful. Furthermore, the morphology alterations were analyzed using scanning electron microscopy images of the sorbent surface. The produced adsorbent particles were also used in the chiral separation of a (±)-NP racemic combination utilizing a column approach, with encouraging separation results shown in both the first loading run (59% ee of R-NP) and the second elution run (85% ee of S-NP).