Über Aminosäure‐Antagonisten, V Trennung und Bestimmung der Konfigurationen der stereoisomeren <i>N</i>‐Acetyl‐2‐(2′‐cyclopentenyl)glycine

Kemmer, Thorsten; Trowitzsch, Wolfram

doi:10.1002/jlac.198119810413

Cited by 21 publications

(15 citation statements)

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“…Deethoxycarbonylation 18 of 5 afforded 6 directly in high yield, avoiding the separate hydrolysis and decarboxylation steps of the previous procedures. 2,10 The resulting mixture of all four stereoisomers (6) was resolved into two racemates, 7 + 8 and 9 + 10, by preparative HPLC on silica gel.…”

Section: Resultsmentioning

confidence: 99%

“…The identity of 11 and 12 could be established by comparisons of their optical rotations with those reported in the literature. 10 Hydrolysis of 11 and 12 afforded free epimeric amino acids 2 and 3 (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, four diastereomeric esters obtained by esterification of the N-acetylamino acid with (R)-2-acetylamino-2-phenylethanol were separated by chromatography and converted to pure stereoisomers of N-acetyl-2-(cyclopent-2Ј-enyl)glycine, the relative and absolute stereochemistry of which was elucidated by combined use of X-ray crystallography, CD spectroscopy, and chemical correlation with N-acetyl-2-cyclopentylglycines. 10 However, the free, stereoisomeric amino acids were not obtained. 10 Subsequently, numerous stereoselective synthetic procedures, which give access to racemic diastereomers of 2-(cyclopent-2Ј-enyl)glycine [11][12][13] or to an optically active mixture of epimers 14 have been developed.…”

mentioning

confidence: 99%

“…10 However, the free, stereoisomeric amino acids were not obtained. 10 Subsequently, numerous stereoselective synthetic procedures, which give access to racemic diastereomers of 2-(cyclopent-2Ј-enyl)glycine [11][12][13] or to an optically active mixture of epimers 14 have been developed. Recently, a fully stereoselective synthetic method leading to the (2S,1ЈS) isomer was described.…”

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confidence: 99%

“…The inhibitory activity of 2-(cyclopent-2Ј-enyl)glycine was reported to be associated with this stereoisomer. 10 In this article, we report a highly efficient procedure which gives easy access to both natural stereoisomers of 2-(cyclopent-2Ј-enyl)glycine, the (2S,1ЈR) isomer 2 and the (2S,1ЈS) isomer 3. The method is based on enzymatic resolution 17 employing ␣-chymotrypsin.…”

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confidence: 99%

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Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

2000

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Both epimers of the naturally occurring nonproteinogenic amino acid L-cyclopentenylglycine, (2S,1'S)- and (2S, 1'R)-2-(cyclopent-2'-enyl)glycine, were obtained via a procedure involving condensation of 3-chlorocyclopentene with diethyl acetylaminomalonate, deethoxycarbonylation, chromatographic separation of the resulting two pairs of enantiomers, and enzymatic resolution of the racemates employing enantioselective hydrolysis of the ethyl ester group with alpha-chymotrypsin. The method was used for preparation of (13)C-labeled compounds of interest for biosynthetic tracer experiments. Enantiomeric purity of the products was determined by chiral HPLC on a Crownpak CR(+) column. The biologically active (2S,1'R) isomer was obtained as a pure compound and characterized for the first time. The (2R,1'R) and (2R,1'S) isomers were obtained as N-acetyl ethyl ester derivatives.

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confidence: 99%

Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

2000

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Synthesis of epimers of L‐cyclopentenylglycine using enzymatic resolution

2000

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Both epimers of the naturally occurring nonproteinogenic amino acid L-cyclopentenylglycine, (2S,1ЈS)-and (2S,1ЈR)-2-(cyclopent-2Ј-enyl)glycine, were obtained via a procedure involving condensation of 3-chlorocyclopentene with diethyl acetylaminomalonate, deethoxycarbonylation, chromatographic separation of the resulting two pairs of enantiomers, and enzymatic resolution of the racemates employing enantioselective hydrolysis of the ethyl ester group with ␣-chymotrypsin. The method was used for preparation of 13 C-labeled compounds of interest for biosynthetic tracer experiments. Enantiomeric purity of the products was determined by chiral HPLC on a Crownpak CR(+) column. The biologically active (2S,1ЈR) isomer was obtained as a pure compound and characterized for the first time. The (2R,1ЈR) and (2R,1ЈS) isomers were obtained as N-acetyl ethyl ester derivatives.

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Biotransformations in the Preparation of Compounds Labeled with Carbon and Hydrogen Isotopes

Voges¹,

Heys

Moenius

2009

Preparation of Compounds Labeled With Tritium and Carbon‐14

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Biotransformations are selective chemical modifications of molecules by biological entities ranging from isolated enzymes (cell-free systems) to intact organisms 1 . In particular cases they are exploited by the chemical and pharmaceutical industries for production of chemicals; this approach can be especially advantageous for structurally complex compounds 2 . Preparative biotransformations have been used on a laboratory scale by radiochemists to prepare isotopically labeled compounds 3 necessary for drug development and other applications in the life sciences. Their synthetic use for isotope labeling includes:. selective modifications of individual functional groups; . synthesis of structurally complex molecules from less complex isotopically labeled precursors; . synthesis of key intermediates for reconstitution approaches to labeled compounds (see Chapter 10).Enzymes are proteins able to catalyze reactions with very high regio-and/or stereoselectivities under mild conditions. Those enzymes combining low substrate specificity (broad applicability) with high product selectivity are of optimal suitability for organic synthesis. Further increase of structural variety and stability by protein-and mediumengineering 4 has extended their synthetic applicability significantly and made them important tools in organic synthesis. The broad scope of their synthetic use is documented in numerous papers, reviews and textbooks 5 . Although successful in particular applications, biotransformations are less common in isotopic labeling.As the complexity of the biological system varies from highly purified enzymes to whole cell-containing systems, so do some of the practical dimensions of the experiments vary. Therefore this chapter is organized accordingly.In one-step biotransformations particularly, isolated enzymes have distinctive advantages, since they can be used simply, almost like any chemical reagent, and -importantly for isotopic labeling -they do not result in any isotope dilution. Since a large number of enzymes are commercially available, many types of reactions can be carried out.Examples of the use of isolated enzymes in isotopic labeling include N-or O-acylations, hydrolyses, redox reactions and group transfer reactions. Most of them aim for applications such as racemate resolution, catalysis of reactions and synthesis of enantiomerically pure molecules. Optical Resolutions via DerivativesDespite the availability of several chemical strategies for diastereo-and enantioselective syntheses in isotopic labeling (see Chapter 11), kinetic racemate resolution remains a major application of enzymes in the chemistry of isotopically labeled compounds. Depending on the molecular entity, different possibilities have been described for achieving enantioselective differentiation through either derivatization (e.g. N-acyl formation and cleavage, O-acyl formation and cleavage) or selective degradation (e.g. redox reactions). N-Acyl Formation: Enzymatically catalyzed N-acylation of racemates is used for preparative synthesis of ...

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Über Aminosäure‐Antagonisten, V Trennung und Bestimmung der Konfigurationen der stereoisomeren N‐Acetyl‐2‐(2′‐cyclopentenyl)glycine

Cited by 21 publications

References 3 publications

Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

Synthesis of epimers of L‐cyclopentenylglycine using enzymatic resolution

Biotransformations in the Preparation of Compounds Labeled with Carbon and Hydrogen Isotopes

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