title: Enantiomeric resolution, stereochemical assignment and toxicity evaluation of TPA enantiomers.
abstract: Tetrahydro-α-(1-methylethyl)-2-oxo-1(2H)-pyrimidineacetic acid (TPA) is a critical intermediate in the synthesis of HIV protease inhibitors. A simple and efficient method for the separation and determination of TPA enantiomers was developed. The TPA was separated into its enantiomers with an enantiomeric purity of 99% using an HPLC system equipped with a Chiralpak OD-H column. Semi-preparative HPLC enantioseparations were carried out for further enrichment of the enantiomers. The validity of this method was evaluated on the basis of its precision, accuracy, linearity and recovery. The method was observed to be suitable for the rapid separation and semi-preparation of TPA isomers. The separated enantiomers were identified by optical rotation and high-resolution electrospray ionization mass spectrometry. Furthermore, the stereochemical structures of the TPA enantiomers were definitively confirmed using a combination of experimental and calculated electronic circular dichroism spectra. The toxicity of the separated pure enantiomers against Oryzias melastigma was evaluated using the median lethal concentration (LC50) values. The results indicated that (S)-(-)-TPA is ~2.5 times more toxic than its enantiomorphism.
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Yulang
authors.initials: Y
authors.lastname: Chi
authors.affiliation: School of Life Sciences and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Wu
authors.affiliation: South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
authors.forename: Sijun
authors.initials: S
authors.lastname: Dong
mesh_terms: D000085:Acetates / Q000737:chemistry* / Q000633:toxicity*; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002942:Circular Dichroism; D017320:HIV Protease Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D009990:Oryzias / Q000502:physiology; D011744:Pyrimidinones / Q000737:chemistry* / Q000633:toxicity*; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; C000621444:tetrahydro-alpha-(1-methylethyl)-2-oxo-1(2H)-pyrimidineacetic acid
keywords: HPLC; TPA; absolute configuration; electronic circular dichroism; enantioseparation