Phosphonic acids, chromatographic

McAlister, D.R., Horwitz, E.P. 2007. Characterization of extraction of chromatographic materials containing bis(2-ethyl-l-hexyl)phosphoric acid, 2-ethyl-1-hexyl (2-ethyl-1-hexyl) phosphonic acid, and bis(2,4,4-trimethyl-l-pentyl)phosphinic acid. Solvent Extraction and Ion Exchange 25(6) 757-769. 

As revealed by a comparison of the chromatographic behavior of 1 and 5 in Fig. 3-101, the introduction of a phenyl group into the molecule results in an increase in the retention at an identical number of phosphonic acid groups. This finding is explained by ji-ji interactions between the stationary phase and the aromatic ring system of the analyte. 

Chromatographic resolutions of aminophosphonic acids are a relatively recent innovation. The resolution of phaclofen, [3-amino-2-(4-chlorophenyl)propyl]phosphonic acid... 

Hexamethylenediamine-tetra(methylene phosphonic acid) (DEQUEST 2051), the analogous compound to EDTP, can be analyzed in the same chromatographic run. 

Two chiral phosphonic acid derivatives 19a,b, containing a stereogenic phosphorus atom connected to a mercaptoisoborneol moiety, were prepared as a mixture, and were then chromatographically separated. Their ability in asymmetric carbonyl olefination was examined in the reaction with 4-tert-butylcyclohexanone la [56). The two lithium carbanions reacted with the carbonyl group of the substrate to give opposite enantiomers 90a, although no remarkable degree of asymmetric induction was observed (up to 16% ee). 

Paper Chromatography.—Solvent systems have been developed for the separation of trichloromethyl- phenyl-, and pentafiuorophenyl-phosphonic and -phosphinic acids. Phosphoramidates and their hydrolysis products have been chromatographed, using triethylamine as a buffer. Silica gel on glass-fibre sheets may be used to separate inositol from its phosphate and to analyse phosphatide glyceryl ethers. ... 

Pyrolysis (in boiling toluene) of the sulphoxide obtained from a dialkyl (l-phenylth> ioalkyl)phosphonate (339) and 3-chloroperoxybenzoic acid affords an alkenephosphonic diester, and subsequent work showed that the sequence was adaptable to the production of chiral esters of alkenylphosphonic diester with optical purities of not less than 93%. Use of the ( S )p-phosphonic amide 340 afforded a mixture of the (E)-(S)p- and (Z)-(S)p-stereoisomers (341), separable by chromatographic methods. ... 

Fig. 4 Ion-pair reversed-phase HPLC-MS/MS chromatogram using heptafluoro-butyric acid (HFBA) as the ion-pair reagent in the mobile phase and a Zorbax SB-Aq column. The standard mixture of alkyl phosphonic adds with a concentration of 10 p-g/ml each was detected using MRM 1) MPA (mh %.8 78.7) 2) EMPA (miz 125 96.8) 3) EDMAPA (miz 154.2 126) 4) iPrMPA (m z 139.1 %.8) 5) PinMPA (m z 181.3 96.8) 6) DiPrMPA (m z 181.3 139.1). See the text for further chromatographic details and the MS/MS conditions used.

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