Amino Sulfonic, Phosphonic, Phosphinic Acids

In yet another study, the simultaneous separation of the four stereoisomers of a-amino-P-hydroxy propane phosphonic acids as well as the corresponding P-amino-a-hydroxy propane phosphonic acids could be successfully accomplished after labeling with Sanger s reagent [119]. 

The applicability of cinchonan carbamate CSPs for bioanalytical investigations using HPLC-ESI-MS/MS has been demonstrated by Fakt et al. [120]. The goal was the stereoselective bioanalysis of (R)-3-amino-2-fluoropropylphosphinic acid, a y-aminobutyric acid (GABA) receptor agonist, in blood plasma in order to determine whether this active enantiomer is in vivo converted to the 5-enantiomer. In this enantioselective HPLC-MS/MS bioassay, sample preparation consisted of 

FIGURE 1.28 Chromatograms of the HPLC enantiomer separation of Z-protected a-aminophosphinic acids (a,b) and phosphinic acid-ilr-dipeptide (c) on (a and b) a 0-9-(tert-butylcarbamoyl)quinidine CSP and (c) corresponding 0-9-(fcrr-butylcarbamoyl)qninine-CSP, respectively. Experimental conditions Column dimensions, 150 mm x 4 mm ID mobile phase, methanol-50 mM sodium phosphate buffer (80 20 v/v) (pHa 5.6) temperature, 40°C flow rate, 1 mLmin detection, UV at 250 nm and optical rotation detection (ORD). (Reproduced from M. Lammerhofer et ah, Tetrahedron Asymmetry, 14 2557 (2003). With permission.) 

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Selected Examples of Enantiomer Separation Data of N-Derivatized Amino Acids (See Also Table 1.3), Amino Sulfonic, Phosphonic and Phosphinic Acids on tBuCQN-Based CSP ... 

FIGURE 1.26 Spectrum of -derivatives of amino acids and corresponding sulfonic, phosphonic, and phosphinic acids for which cinchonan carbamate-based eSPs showed broad enantiomer separation capabilities. 

Water-soluble mono- and diphosphines represent the major class of phosphines used in aqueous-phase homogeneous catalysis. However, some new types of water-soluble phosphines have been developed, including phosphines containing sugar substructures [31] or phosphonate chains [32], and chiral sulfonated phosphines for the asymmetric hydrogenation of dehydropeptides [33] and phosphines with amino acid moieties [59]. 

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