Design of molecularly imprinted resin material with sulfonic acid functionalization for enantioseparation of (±)-cathine.

In the current work, an enantioselective imprinting technique was used to develop a very selective adsorbent for the (+)-cathine ((+)-Cat) enantiomer. The phenolic sulfonamide produced from 2,4-dihydroxybenzenesulfonic acid (HBS) and (+)-Cat ((+)-Cat-HBS) was initially synthesized by triphenylphosphene activation and subsequently involved in condensation polymerization with resorcinol in the presence of formaldehyde under acidic conditions. Alkaline sulfonamide bond-breaking was subsequently employed to separate the (+)-Cat template from the polymer, and the resulting imprinted resin ((+)-CIP) displayed high selectivity for the (+)-Cat, with a capacity of 225 ± 2 mg/g. Studies of selectivity also showed that the (+)-Cat enantiomer was preferred over its counterpart because of the development of configurationally matching receptors. In addition, the produced resin was used for the enantioresolution of (±)-Cat racemate by column method, yielding a loading supernatant solution with an enantiomeric excess of (+)-Cat 50% and a recovery eluant solution with an excess of (-)-Cat 85%.