Efficient Enantiodifferentiation of Carboxylic Acids Using BINOL-Based Amino Alcohol as a Chiral NMR Solvating Agent

Gaowei Li; Minshan Ma; Guifang Wang; Xiaojuan Wang; Xinxiang Lei

doi:10.3389/fchem.2020.00336

Efficient Enantiodifferentiation of Carboxylic Acids Using BINOL-Based Amino Alcohol as a Chiral NMR Solvating Agent

Front Chem. 2020 May 4:8:336. doi: 10.3389/fchem.2020.00336. eCollection 2020.

Authors

Gaowei Li¹, Minshan Ma², Guifang Wang², Xiaojuan Wang¹, Xinxiang Lei²

Affiliations

¹ College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, China.
² School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, China.

Abstract

A new optically active BINOL-amino alcohol has been designed and synthesized in a good yield and applied as chiral nuclear magnetic resonance (NMR) solvating agent for enantioselective recognition. Analysis by ¹H NMR spectroscopy demonstrated that it has excellent enantiodifferentiation properties toward carboxylic acids and non-steroidal anti-inflammatory drugs (14 examples). The non-equivalent chemical shifts (up to 0.641 ppm) of various mandelic acids were evaluated by the reliable peak of well-resolved ¹H NMR signals. In addition, enantiomeric excesses of the ortho-chloro-mandelic acid with different enantiomeric ratio were calculated based on integration of proton well-separated splitting signals.

Keywords: 1H NMR analysis; BINOL-amino alcohol; carboxylic acids; chiral discrimination; chiral-solvating agents.