Liquid chromatographic methods for separation, determination, and bioassay of enantiomers of etodolac: A review was written by Singh, Manisha;Sethi, Sonika;Bhushan, Ravi. And the article was included in Journal of Separation Science in 2020.Quality Control of 2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetic acid This article mentions the following:
The control of enantiomeric purity and determination of individual enantiomeric drug mols. remains the subject of importance for clin., anal., and regulatory purposes and to facilitate an accurate evaluation of the risks posed by them to human health. A large number of pharmaceuticals are marketed and administered as racemates. Etodolac is among such nonsteroidal anti-inflammatory drugs. Overall literature reports on its enantioseparation are scanty. Liquid chromatog. (LC) methods of enantioseparation of (±)-etodolac, including certain unconventional ones, are well covered and discussed in this paper. Methods of direct approach without using chiral columns or chiral thin-layer chromatog. plate and of indirect approach using certain chiral derivatizing agents such as (S)-naproxen and (S)-levofloxacin are described. Most interesting aspects include establishment of structure and mol. asymmetry of chem. different types of diastereomeric derivatives using liquid chromatog. with mass spectrometry (LC-MS), 1H NMR spectroscopy and by drawing conformations in three dimensional views by using certain software. The methods provide chirality recognition even in the absence of pure enantiomers. Besides, recovery of pure enantiomers by detagging or via solubility difference of chiral inducing reagent and the analyte, without racemization at any stage, has been achieved. The limits of detection and quantification are much lower than the industry benchmarks. In the experiment, the researchers used many compounds, for example, 2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetic acid (cas: 41340-25-4Quality Control of 2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetic acid).
2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetic acid (cas: 41340-25-4) belongs to tetrahydropyran derivatives. Dihydropyrans and tetrahydropyrans are examples of cyclic ethers widespread in nature. The reaction of tertiary 1,4- and 1,5-diols with cerium ammonium nitrate at room temperature gives tetrahydrofuran and tetrahydropyran derivatives in high yield and stereoselectivity. Various fragrant compounds have been synthesized using this method.Quality Control of 2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetic acid
Referemce:
Tetrahydropyran – Wikipedia,
Tetrahydropyran – an overview | ScienceDirect Topics