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Liquid chromatographic enantioseparation of ( RS )‐etodolac using ( S )‐levofloxacin and determination of absolute configuration of the diastereomeric derivatives
Author(s) -
Singh Manisha
Publication year - 2019
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.4415
Subject(s) - diastereomer , etodolac , chemistry , chromatography , racemization , reagent , derivatization , enantiomer , high performance liquid chromatography , chirality (physics) , absolute configuration , organic chemistry , biochemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
( RS )‐Etodolac was isolated from commercial tablets and was purified and characterized to be used as racemic standard. A pair of diastereomeric derivatives was synthesized using ( S )‐levofloxacin as a chiral derivatizing reagent. The derivatization reaction was carried out under conditions of stirring at room temperature (30°C for 1.5 h) as well as under microwave irradiation; the derivatives obtained by the two methods were compared. Reaction conditions for derivatization were optimized with respect to mole ratio of chiral derivatizing reagent and ( RS )‐etodolac. No racemization was observed throughout the study. Separation of diastereomeric derivatives was successful using C 18 column and a binary mixture of methanol and triethyl ammonium phosphate buffer of pH 4.5 (80:20, v/v) as mobile phase at a flow rate of 1 mL min −1 and UV detection at 223 nm. An efficient approach for recognizing chirality and determining the absolute configuration of the diastereomeric derivatives of ( RS )‐etodolac is described, which in turn is a measure of the enantiomeric purity of ( RS )‐etodolac since the diastereomeric derivatives were separated and isolated using preparative thin‐layer chromatography.