Norephedrine chromatography

A similar condensation of (+)-norephedrine (121) gave the corresponding 2-methyl-1,3,2 oxazaphospholidine-2-thiones 122a,b which were separated by rapid, medium pressure chromatography (Scheme 35) [67],... 

These methods have recently been extended to the preparation of enantiomeri-cally pure sulfoximines from optically active sulfonimidates. For example, Pyne11 prepared the optically active diastereomeric sulfoximines 4 and 5 from the reaction of the phenyl sulfonimidate 3 and methyllithium. Compound 3 was prepared from (+)-norephedrine as a 1.8 1 mixture of diastereoisomers that could not be separated chromatographically. The sulfoximines 4 and 5 were readily separated by column chromatography in isolated yields of 14 and 28%, respectively. A related method to prepare optically active N-(S)-1 -phenylethyl-S-methy 1-S-phenylsulfoximines has also been reported.12... 

Gas Chromatography. System GA—diethylpropion RI 1486, norephedrine RI 1313 system GB—diethylpropion RI 1507, norephedrine RI 1353 system GC—diethylpropion RI 1715, norephedrine RI 1383 system GF—diethylpropion RI 1655. 

High Pressure Liquid Chromatography. System HA—diethylpropion k 1.7, norephedrine k 0.9 system HC—diethylpropion k 0.16, norephedrine k 0.70. 

Sagara K, Oshima T, Misaki T. A simultaneous determination of norephedrine, pseudoephedrine, ephedrine and methylephedrine in Ephedrae Herba and oriental pharmaceutical preparations by ion-pair high-performance liquid chromatography. Chem Pharm Bull (Tokyo) 1983 31(7) 2359-2365. 

Figure 5 High-performance strong cation-exchange chromatography of ephedrine alkaloids and synephrine in dietary supplements. UV and fluorescence chromatograms of (A) standard solution ( 3 ng per component, except 1.6 tg of component 1), (B) Xenadrine RFA-1, (C) Xetalean, and (D) Ultra Diet Pep. Analytes 1, ( )-synephrine 2, (-)-norephedrine 3, (+)-norpseudoephedrine-HCI 4, (-)-ephedrine-HCI 5, (+)-pseudoephedrine 6, (-)-A/-methylephedrine 7, (+)-N-methylpseudoephedrine. Reproduced from R. A. Niemann M. L. Gay, J. Agric. Food Chem. 2003, 51, 5630-5638.

Domon, B. Hostettmann, K. Kovacevic, K. Prelog, V. Separation of the enantiomers of ( )-norephedrine by rotation locular counter-current chromatography. J. Chromatogr. 1982, 250, 149-151. 

For the chiral resolution of racemic norephedrine, an aqueous phase containing 0.5M sodium hexafluorophosphate at pH 4 was utilized as the stationary phase with a mobile phase of 1,2-dichloroethane containing 0.3M (R,R)-5-nonyl-tartrate. The racemic norephedrine forms diastereotopic complexes 10a and 10b, which have different partitioning characteristics, whereby the nonyl-residues maintain the solubility in the organic phase. Such applications of a chiral template for the resolution of racemic mixtures via liquid-liquid chromatography should have a broad range of possibilities. 

Optically active allylboronates bearing chiral auxiliary located at the boron atom found widespread applications in asymmetric synthesis. Enantiomerically enriched a-alkylidene-y-lactones and lactams can also be synthesized following such a synthetic approach. VUlieras et al. (41, 45] demonstrated the potential of chiral allylboronates derived from 2-phenyl-2,3-bomanediol, ephedrine, or norephedrine for this purpose. Chiral allylboronates 46a,b were obtained in a sequence of reactions involving transformation of achiral precursors 32 into the corresponding boronic acids 44 followed by their esterification with enantiomerically pure diol or 1,2-aminoalcohol 45 (Scheme 4.10). In the case of methyl-substituted derivatives 32b (R = Me), initial composition of E- and Z-isomers was transferred to the target allylboronates 46b. Importantly, the isomeric mixture was separated by means of the column chromatography. 

Kaddoumi, A. Kubota, A. Nakashima, M.N. Takahashi, M. Nakashima, K. High performance liquid chromatography with UV detection for the simultaneous determination of sympathomimetic amines using 4-(4,5-diphenyl-lH-imidazole-2-yl)benzoyl chloride as a label, Biomed.Chromatogr., 2001, 15, 379-388. [human rat plasma derivatization LOD 50-100 nM ephedrine norephedrine 2-phenylethylamine fenfluramine phentermine cyclohexylamine fluoxetine is internal standard pharmacokinetics]... 

Kaddoumi, A. Nakashima, M.N. Nakashima, K. Fluorometric determination of DL-fenfluramine, DL-norfenfluramine and phentermine in plasma by achiral and chiral high-performance liquid chromatography, J.Chromatogr.B, 2001, 763, 79-90. [fluorescence detection derivatization human rat LOD 10 nM ephedrine norephedrine]... 

Successively, Suedee et al. [48] used MIP plates prepared by thermal polymerization methods and imprinted with (+)-ephedrine, (+)-pseudoephedrine, and (+)-norephedrine for the separation of a-agonists, -agonists, and -antagonists using mixtures of 5 or 10% acetic acid in methanol or dichloromethane as mobile phases in planar chromatography. Propanolol, pindolol, and oxprenolol were baseline separated by all the polymers imprinted with the aforementioned a-agonists with a-values ranging from 1.43 to 2.16. 

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