Bi-naphthol enantiomers

The chromatographic resolution of bi-naphthol enantiomers was considered for simulation purposes [18]. The chiral stationary phase is 3,5-dinitrobenzoyl phenyl-glycine bonded to silica gel and a mixture of 72 28 (v/v) heptane/isopropanol was used as eluent. The adsorption equilibrium isotherms, measured at 25 °C, are of bi-Langmuir type and were proposed by the Separex group ... 

The resolution of the bi-naphthol enantiomers was used for simulation purposes. A reference case relative to a 8-column configuration of the SMB, based on the values of operating variables and model parameters shown in Table 9-4 was chosen. 

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]. 

Pais L. S., Loureiro J. M., Rodrigues A. E. (1997b) Modeling, Simulation and Operation of a Simulated Moving Bed for Continuous Chromatographie Separation of l,l -bi-2-naphthol Enantiomers, J. Chromatogr. A 169 25-35. 

Pais, L., Loureiro, J., Rodrigues, A. Separation of l,l-bi-2-naphthol enantiomers by continuous chromatography in simulated moving bed, Chem. Eng. Sci., 1997a, 52, 245-257. 

Figure 4, Chiral recognition model showing the relative arrangement for three simultaneous bonding interactions between (K)-CSP 1 and the most retained enantiomer of bi- -naphthol.

Pais, L., Lourerro, J., and Rodrigues, A. (1997b) Modeling, simulation and operation of a simulated moving bed for continuous chromatographic separation of l,l-bi-2-naphthol enantiomers./. Chromatogr. A, 769, 25—35. 

In another study of Pais et al. [18, 19] the enantiomer separation of 1, I -bi-naphthol was investigated in a commercial SMB plant (Licosep 12-26, Separex, France). For the separation, 8 columns of an inner diameter of 26mm were used. 

Chiral diols and tartrates have been studied as metal complexes as well. The enantiomers of l,l -bi-2-naphthol (Y) and diisopropyltartrate (T) have been... 

When optically inactive polystyrene was used as adsorbent, no difference in the relative peak intensity at m/z 288 to 286 was detected. Moreover, in the resolution of (RS)-1,1 -bi-2-naphthol and (if5)-l,l,-bi-2-naphthol-rf2 on the CSP, no isotope effect was observed. These findings indicate that the difference in EI-MS spectra is due to the difference in desorption between the enantiomers from the chiral adsorbent tris(5-f uoro-2-methylphenylcarbamate). This method can be used to discriminate the chirality of other enantiomers of small molecules if they show peaks in their EI-MS spectra in the presence of chiral polymers. Similar chiral recognition was detected by negative ion fast-atom bombardment mass spectrometry [34],... 

Pyridinecarbaldehyde reacts with trimethylsilyl cyanide in the presence of the catalysts derived from either enantiomer of 3,3 -bis(diethylaminomethyl)-substituted binaphthol or 1,1 -bi-2-naphthol (BINOL) and... 

The symmetry properties of cycloaliphatic polymers are such that polymers with certain microstructures, e.g. tram-isotactic poly (methylene-1,3-cyclopen-tane), are chiral therefore, the cyclopolymerisation of a, trans selective catalysts of C2 symmetry, such as methylaluminoxane-activated resolved (li )-(Thind CH2)2Zr l,l -bi-2-naphtholate, yielded optically active tram-isotactic poly(-methylene-1,3-cyclopentane). The cyclopolymerisation with the (15) enantiomer of the catalyst gave an enantiomeric polymer [505], On the basis of analysis of 13C NMR spectra, the degree of enantioface selectivity for this cyclopolymerisation was estimated to be of 91% [503,505]. 

Pirkle CSPs have been used for LC separations of the enantiomers of alcohols, sulfoxides, bi-(3-naphthols, (3-hydroxysulfides, heterocycles such as hydantoins, succinimides, and agents related to propranolol. These phases have also been used in SFC for the separation of phosphine oxide enantiomers.40... 

If bi-2-naphtol was stereoselectively oxidized, the kinetic resolution of bi-2-naphthol was achieved. Actually, the S enantiomer of bi-2-naphtol is more rapidly consumed than the R enantiomer with an enantiomer excess of 15.2% after 1 h and 2 h reactions and 11.0% after a 12 h reaction. 

Initially, studies on the preparation of the borate complexes of the type 3 using bi-2-naphthol, S-proline and B(OH)3 were carried out. These experiments revealed that the bi-2-naphthol and S-proline form a 2 1 diastereomeric inclusion complex in the absence of boric acid (Scheme l).5 Unfortunately, efforts to improve the optical purity through crystallisation did not yield fruitful results. However, both the enantiomers can be obtained in pure forms by carrying out the experiments again using the partially resolved samples.5... 

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