Dinitrobenzoyl-phenylglycine

Pirkle DNPG (/ )-N-3,5-Dinitrobenzoyl-phenylglycine covalently bonded to aminopropyl silica. 

The separation of bi-naphthol enantiomers can be performed using a Pirkle-type stationary phase, the 3,5-dinitrobenzoyl phenylglycine covalently bonded to silica gel. Eight columns (105 mm length) were packed with particle diameter of 25 0 fiva. The solvent is a 72 28 (v/v) heptane isopropanol mixture. The feed concentration is 2.9 g for each enantiomer. The adsorption equilibrium isotherms were determined by the Separex group and already reported in Equation (28) [33]. 

In a flame-dried Schlenk tube 0.37 g(1.88 mmol) of (-)-3-exo-(dimethylamino)isoborneol (C) and 200 mL of dry toluene are placed under an atmosphere of argon. 27 mL of 4.2 M diethylzinc (113 mmol) in toluene are added and the resulting solution is stirred at 15°C for 15 min. After cooling to — 78°C, lOg (94.2 mmol) of benzaldehyde are added and the mixture is wanned to O C. After stirring for 6 h, the reaction is quenched by the addition of sat. NH4C1 soln. Extractive workup is followed by distillation yield 12.4 g (97%) 98% ee [determined by HPLC analysis. Baseline separation of rac-1 -phenyl-1 -propanol was achieved on a Bakerbond dinitrobenzoyl phenylglycine column (eluent 2-propanol/hexanc 1 3 flow rate l.OmL/ min detection UV 254 nm)] [a] 0 —47 (c = 6.11, CHC13). 

Chiral sulfoxides with at least one sulfur-bonded aryl group have been separated by liquid chromatography into the enantiomers26. Some of the columns employed, which are commercially available, used 3,5-dinitrobenzoyl)phenylglycine bonded to silica... 

The solvent used was hexane-isopropanol(4 1). Later, Allenmark and colleagues obtained enantioselective HPLC retention of a series of alkyl carboxymethyl sulphoxides (and other sulphoxides and classes) on a column of (R)-lV-(3,5-dinitrobenzoyl)phenylglycine covalently bound via an amide bond (CSP 1), or ionically bound (CSP 2), to 3-aminopropylsilica the mobile phase was again hexane-isopropanol(4 l, or, also 19 1) and determination carried out at 254 or 280nm. The sulphoxides were better resolved on CSP 2. 

Figure 4. CSP-HPLC separation of the enantiomers of BaP dihydro- and tetrahydro- trans-7,8-diol and trans-9.10-diol. A column (4.6 mm ID x 25 cm) of y-aminopropylsilanized silica with ionically bonded (R)-N-(3,5-dinitrobenzoyl)phenylglycine was eluted with 18% (v/v) of ethanol/acetonitrile (2 1, v/v) in hexane at a solvent flow rate of 2 ml/min.(Reproduced with permission from Ref. 20.

A commercially packed h.p.l.c. column (25 cm x 4.6 mm) of y-aminopropyl silanised silica [e.g. 5/mi Spherisorb (Regis Chemical Co.), or 7/im Zorbax (Dupont Co.), or 10 /im Lithosorb (Merck), or 5 m irregular (J. T. Baker Chemical Co.)] was sequentially treated, at a pumping rate of 2 ml/min, with the following solutions 2 ml of triethylamine in 40 ml of dry tetrahydrofuran, 2g of (R)-JV-(3,5-dinitrobenzoyl)phenylglycine in 40 ml of dry tetrahydrofuran, 20 ml of dry tetrahydrofuran, and finally 10 per cent propan-2-ol in hexane, until the base line stabilises. The chiral amino acid derivative (which is available from Aldrich Chemical Co.) becomes ionically bonded to the amino residues on the stationary phase. 

The first ionically bonded phase was presented by Pirkle it contained (/ )-3,5-dinitrobenzoyl phenylglycine [13]. The most commonly used 7t-acid moiety is the 3,5-dinitrophenyl group introduced by the reaction of 3,5-dinitrobenzoyl chloride (DNB-C1) on chiral selectors such as amino acids, amino alcohols, and amines. In addition, pentafluorobenzoyl derivatives have also been reported [14,15]. The 7r-basic phases are complimentary to the re-acidic phases. These CSPs include the presence of phenyl- or alkyl-substituted phenyl groups. Macaudiere et al. [9] designed a CSP containing both re-acidic and re-basic... 

FIGURE 3 The chemical pathway for the preparation of 3,5-dinitrobenzoyl phenylglycine CSP (Pirkle type). 

Note DNBGP=3,5-dinitrobenzoyl phenylglycine DNBLeu=3,5-dinitrobenzoyl leucine. 

FIGURE 13 A comparison of the chiral resolution of 2-naphthyl amide derivatives of 2-aminooctane enantiomers on 3,5-dinitrobenzoyl phenylglycine CSP by HPLC and SFC using ( ) hexane-2-propanol (95 5, v/v), ( ) carbon dioxide-2-propanol (95 5, v/v), and ( ) carbon dioxide-2-propanol-water (95 4.8 0.2, v/v/v) as the mobile phases. (From Ref. 9.)... 

Analytical Properties Higher selectivity for nitrogen-containing racemates than fl-/V-(3,5-dinitrobenzoyl) phenylglycine examples of nitrogen-containing racemates include succinimides, hydantoins, and mandelates Reference 41... 

The pioneering work in the area of chiral 77-donor and 77-acceptor phases was done by Pirkle and co-workers,98,99 and the most frequently used 77-acceptor phase is still an (/ )-7V-(3,5-dinitrobenzoyl)phenylglycine phase, the so-called Pirkle phase. With these stationary phases, chiral recognition is based on 77-77 interactions, dipole stacking interactions, and hydrogen bonding.100... 

In another approach, reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been employed for the preparation of chiral HPLC packings. Thus, reactive chloromethyl groups were derivatized to yield amino functionalized beads onto which both rt-basic and rt-acidic type chiral. selectors, (/ )- -(l-naphthyl)ethylamine and (/ )-A -(3.5-dinitrobenzoyl)phenylglycine, respectively, were attached. The resulting chiral particles were chromatographically tested for the enantioseparation of model SAs. Despite the presence of strongly competitive it-TT-binding sites of the styrenic support these chirally modified beads afforded baseline separations for 2,2,2-trifluoro-l-(9-anthryl) ethanol and Af-(3.5-dinitro-benzoyl) leucine enantiomers, respectively [369. ... 

Figure 10.3 Representative bonded chiral phases for HPLC. (I) Pirkle phase (II) N-(3, 5-dinitrobenzoyl) phenylglycine ionically bonded to 3-asinopropylsilanized silica (III) N-n-valeryl-L-valyl-3-aminopropylsilanized silica (IV) R-(-)-2-(2-4-5-7-tetranitro-9-fluorenylideneaminooxy) propionamidepropyl silanized silica.

Figure 6.4 Pirkle stationary phases showing IV-(3,5-dinitrobenzoyl)phenylglycine, ionically and covalently bonded to an aminopropyi silica.

Silica with monomolecular ligands (Brush-type CSP) 3-[N-(3,5-dinitrobenzoyl) phenylglycin-amido]propyl-silica... 

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