First synthesis of the two enantiomers of α‐methyldiphenylalanine [(αMe)Dip] by HPLC resolution

Royo, Soledad; López, Pilar; Jiménez, Ana I.; Oliveros, Laureano; Cativiela, Carlos

doi:10.1002/chir.10036

Cited by 21 publications

(4 citation statements)

References 45 publications

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“…These so‐called immobilized phases retain the advantages of coated polysaccharide‐based phases while being compatible with a wide variety of organic solvents, a feature of enormous value for preparative‐scale resolution. We have successfully applied such chiral stationary phases, either made at the laboratory (prior to their commercialization) or of the Chiralpak type, to the preparative HPLC resolution of non‐natural analogs of proline, valine, and phenylalanine with diverse structures.…”

Section: Resultsmentioning

confidence: 99%

Access to Enantiomerically Pure cis‐ and trans‐β‐Phenylproline by High‐Performance Liquid Chromatography Resolution

et al. 2012

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The preparation of all four stereoisomers of the proline analogue that bears a phenyl group attached to the β carbon either cis or trans to the carboxylic acid (cis-and trans-β-phenylproline, respectively) has been addressed. The methodology developed allows access to multigram quantities of the target amino acids in enantiomerically pure form and suitably protected for use in peptide synthesis. Racemic precursors of cis-β-phenylproline and trans-β-phenylproline were prepared from easily available starting materials and subjected to HPLC enantioseparation. Semipreparative columns (250 mm × 20 mm) containing chiral stationary phases based on amylose (Chiralpak ® IA) or cellulose (Chiralpak ® IC) were used, respectively, for the resolution of the cisand trans-β-phenylproline precursors.

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Section: Resultsmentioning

confidence: 99%

Access to Enantiomerically Pure cis‐ and trans‐β‐Phenylproline by High‐Performance Liquid Chromatography Resolution

et al. 2012

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“…R f (hexane/EtOAc, 8:2) ϭ 0. 58 Methyl trans-1-Cyano-2-phenylcyclohexylcarbamate (rac-5): PCl 5 (0.21 g, 1 mmol) was added to a solution of carboxylic acid rac-4 (229 mg, 1 mmol) in dry Et 2 O (10 mL). The reaction mixture was stirred at room temperature for 90 min.…”

Section: Methyl Trans-1-cyano-6-phenyl-3-cyclohexenecarboxylate (Rac-mentioning

confidence: 99%

Synthesis and Preparative Resolution of the trans‐Cyclohexane Analogues of Phenylalanine

2004

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Different approaches to the synthesis of enantiomerically pure (1R,2S)‐ and (1S,2R)‐1‐amino‐2‐phenylcyclohexanecarboxylic acids (trans‐c6Phe) through a racemic pathway followed by semi‐preparative HPLC of a racemic precursor have been studied. The complete diastereoselectivity of the Strecker reaction and the high efficiency of the subsequent transformations into the amino acid favour this method in comparison to the Diels−Alder route. The relative stereochemistry of the amino acid and its precursors has been unambiguously assigned. The preparation of the final enantiomerically pure amino acids and their corresponding N‐Boc derivatives was carried out by HPLC resolution of one of the intermediates using a cellulose‐derived chiral stationary phase. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…[64][65][66][67][68][69][70][71][72][73][74][75][76] For example, topologically interesting catenanes, 67 molecular knots, 71,72 and knotaxane, 73 which is rotaxane with knots as stoppers, have been completely resolved on CSP-32 using a hexane/chloroform/2-propanol mix- ture ( Figure 18). In addition, the linear, branched, and cyclic knotane oligomers can be sufficiently resolved with an eluent containing chloroform ( Figure 19).…”

Section: Enantioseparations With Eluents Containing Chclmentioning

confidence: 99%

Immobilized Polysaccharide-Based Chiral Stationary Phases for HPLC

Ikai

Yamamoto

Kamigaito

et al. 2006

Polym J

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ABSTRACT:Polysaccharide derivatives, such as phenylcarbamates and benzoates of cellulose and amylose, are known to show high chiral recognition abilities for many racemates when used as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). This type of CSPs has usually been prepared by coating the polysaccharide derivatives onto a macroporous silica gel without a chemical bond. Therefore, rather limited numbers of solvents can be used as eluents, and solvents, such as chloroform and tetrahydrofuran (THF), which swell or dissolve the polysaccharide derivatives cannot be used. The selection of a suitable eluent is very important for both analytical and preparative separations. In order to enhance the versatility of the polysaccharide derivative-based CSPs, the derivatives have to be immobilized. Here we review the immobilization methods of the polysaccharide derivatives mainly onto silica gel. [DOI 10.1295/polymj.38.91] KEY WORDS Immobilization / Polysaccharide / Resolution / High Performance Liquid Chromatography / HPLC / Chiral Stationary Phase / CSP / Optically active compounds have been attracting much attention in many fields of science, and the demand for single enantiomers in the pharmaceutical industry has also been increasing. However, the separation or resolution of enantiomers is often laborious because most physical and chemical properties of enantiomers are identical. In the early 1970s, the first baseline separation of enantiomers by liquid chromatography was reported by Davankov, 1 and in 1981, the chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) developed by Pirkle 2 were for the first time commercialized. In the 1980s, the instrumentation for HPLC had remarkably advanced, and many efficient CSPs for HPLC had also been developed. [3][4][5][6][7][8][9] Today, most chiral compounds appear to be resolved by HPLC using CSPs. 10 The CSPs have been prepared with optically active small molecules 6,8,11 or polymers, [3][4][5][6][7][12][13][14][15] which are usually supported on silica gel. Among a large number of CSPs so far developed, phenylcarbamates of cellulose and amylose (Figure 1) exhibit broad applicability to a wide range of compounds. 10,[16][17][18][19][20][21] Some of the polysaccharide-based CSPs for HPLC have been commercially available. However, these polysaccharidebased CSPs can be used with a limited number of solvents, because some organic solvents, such as THF, chloroform, toluene, ethyl acetate, and acetone, dissolve or swell the polysaccharide derivatives and destroy their packed columns. Due to this solubility of the polysaccharide derivatives, the coated CSPs have usually been used with eluents consisting of alkanes/ alcohols mixtures or aqueous solvents containing alcohols or acetonitrile. These limitations in the mobile phase selection are sometimes a serious problem for efficient analytical and preparative resolution of enantiomers. 10,22 For a large scale preparative separation, good solubility of the sample is essen...

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First synthesis of the two enantiomers of α‐methyldiphenylalanine [(αMe)Dip] by HPLC resolution

Cited by 21 publications

References 45 publications

Access to Enantiomerically Pure cis‐ and trans‐β‐Phenylproline by High‐Performance Liquid Chromatography Resolution

Access to Enantiomerically Pure cis‐ and trans‐β‐Phenylproline by High‐Performance Liquid Chromatography Resolution

Synthesis and Preparative Resolution of the trans‐Cyclohexane Analogues of Phenylalanine

Immobilized Polysaccharide-Based Chiral Stationary Phases for HPLC

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