Chemo-enzymatic approach to d-allo-isoleucine

Cambiè, Mara; D’Arrigo, Paola; Fasoli, Elisa; Servi, Stefano De; Tessaro, Davide; Canevotti, Francesco; Corona, L. Del

doi:10.1016/j.tetasy.2003.08.009

Cited by 10 publications

(4 citation statements)

References 38 publications

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“…The preparation of these nonprotein stereoisomers is therefore attracting attention and has been carried out by various methods, such as asymmetric syntheses (Lloyd-Williams et al, 1994;Portonovo et al, 1999), chemoenzymatic methods (Murayama et al, 2005;Cambiè et al, 2003) and resolving methods (Huffman & Ingersoll, 1951;Flouret & Nakagawa, 1975;Noda et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation

Yajima

Kimura

Hori

et al. 2016

Acta Crystallogr Sect B

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The crystal structures of N-acetyl-DL-isoleucine, N-acetyl-DL-alloisoleucine and their ammonium salts show that these four compounds exist as racemic compounds around room temperature. The two ammonium salts are arranged around a 21 screw axis, forming a helical column which consists of ammonium ions and single enantiomeric anions similar to the crystals of the ammonium salts of optically active N-acetyl-L-isoleucine and N-acetyl-D-alloisoleucine. The ammonium ion and the carboxylate ion in the helix are connected by three hydrogen bonds, the fourth hydrogen bond being formed between the ammonium ion and an external acetyl amino group of the neighboring helical column. The fourth hydrogen bond is formed between the ammonium ion and an external acetyl amino group of the neighboring 21 column. Ammonium N-acetyl-DL-alloisoleucinate was revealed to exist as an unstable racemic compound due to conformational similarity between the racemic and optically active compounds in the solid state and was optically resolved by fractional crystallization at 293 K.

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Section: Introductionmentioning

confidence: 99%

Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation

Yajima

Kimura

Hori

et al. 2016

Acta Crystallogr Sect B

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“…The synthesis of the dipeptide fragment of the cystargolides started by union of L-isoleucine benzyl ester (−)- 8 24 with N -Boc valine, 25 using standard amino acid coupling conditions 26 to give (−)- 9 (Scheme 2). The Boc protecting group was then cleaved under acidic conditions, and the resulting dipeptide trifluoroacetate salt was used directly in the coupling reaction with carboxylic acids (−)- 7 and (+)- 7 separately to give (−)- 10 and (−)- 11 , respectively.…”

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confidence: 99%

Total synthesis and absolute stereochemistry of the proteasome inhibitors cystargolides A and B

et al. 2015

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“…3) D-aIle is prepared by a variety of procedures, e.g., asymmetric synthesis from (S)-2-methyl-1-butanol, 4,5) chemoenzymatic methods, 6,7) and some resolving methods. 6) or alcalase 7) with laborious procedures.…”

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confidence: 99%

“…6) or alcalase 7) with laborious procedures. On the other hand, a diastereoisomeric mixture can be easily separated by managing the chiral derivatives of amines 9) or tartaric acid, 10) but the diastereoisomers can be separated without using chiral resolving reagents, as we have shown in the previous report.…”

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confidence: 99%

Structures and Properties of a Diastereoisomeric Molecular Compound of (2S,3S)- and (2R,3S)-N-Acetyl-2-amino-3-methylpentanoic Acids

Yajima

Kimura

Nakakoji

et al. 2009

Bioscience, Biotechnology, and Biochemistry

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An X-ray crystal structural analysis revealed that (2S,3S)-N-acetyl-2-amino-3-methylpentanoic acid (Nacetyl-L-isoleucine; Ac-L-Ile) and (2R,3S)-N-acetyl-2-amino-3-methylpentanoic acid (N-acetyl-D-alloisoleucine; Ac-D-aIle) formed a molecular compound containing one Ac-L-Ile molecule and one Ac-D-aIle molecule as an unsymmetrical unit. This molecular compound is packed with strong hydrogen bonds forming homogeneous chains consisting of Ac-L-Ile molecules or Ac-DaIle molecules and weak hydrogen bonds connecting these homogeneous chains in a fashion similar to that observed for Ac-L-Ile and Ac-D-aIle. Recrystallization of an approximately 1:1 mixture of Ac-L-Ile and Ac-D-aIle from water gave an equimolar molecular compound due to its lower solubility than that of Ac-D-aIle or especially Ac-L-Ile. The results suggest that the equimolar mixture of Ac-L-Ile and Ac-D-aIle could be obtained from an Ac-L-Ile-excess mixture by recystallization from water.

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Chemo-enzymatic approach to d-allo-isoleucine

Cited by 10 publications

References 38 publications

Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation

Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation

Total synthesis and absolute stereochemistry of the proteasome inhibitors cystargolides A and B

Structures and Properties of a Diastereoisomeric Molecular Compound of (2S,3S)- and (2R,3S)-N-Acetyl-2-amino-3-methylpentanoic Acids

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