Crystal structure ofN-(tert-butoxycarbonyl)glycyl-(Z)-β-bromodehydroalanine methyl ester [Boc–Gly–(β-Br)(Z)ΔAla–OMe]

Lenartowicz, Paweł; Makowski, Maciej; Zarychta, Bartosz; Ejsmont, Krzysztof

doi:10.1107/s1600536814025677

Cited by 2 publications

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“…αβ‐Didehydro‐α‐amino acids, commonly known as dehydroamino acids (ΔXaa), belong to nonstandard amino acids occurring primarily in natural peptides produced by bacteria and fungi . Dehydroamino acids continuously attract attention in various areas, mainly in synthesis, as designed products or suitable substrates, including asymmetric hydrogenation as well as in the conformational studies . Dehydrophenylalanine (ΔPhe), although scarcely presented in natural compounds, is the most often studied dehydroamino acid .…”

Section: Introductionmentioning

confidence: 99%

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

et al. 2016

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Dehydrophenylalanine, ΔPhe, is the most commonly studied α,β-dehydroamino acid. In nature, further modifications of the α,β-dehydroamino acids were found, for example, replacement of the C-terminal amide group by oxazole ring. The conformational properties of oxazole-dehydrophenylalanine residue (ΔPhe-Ozl), both isomers Z and E, were investigated. To determine all possible conformations, theoretical calculations were performed using Ac-(Z/E)-ΔPhe-Ozl(4-Me) model compounds at M06-2X/6-31++G(d,p) level of theory. Ac-(Z/E)-ΔPhe-Ozl-4-COOEt compounds were synthesized and the conformational preferences of each isomer, Z and E, were investigated using FTIR and NMR-NOE in solutions of increasing polarity (CHCl3 , DMSO-d6). The solid-state low-temperature structures of Ac-(Z)-ΔPhe-Ozl-4-COOEt and its intermediate analog Ac-(Z)-ΔPhe-Ozn(4-OH)-4-COOEt were also determined. In a weakly polar environment, the ΔPhe-Ozl residue has a tendency to adopt the conformation β2 with the calculated φ and ψ angles of -127° and 0° for the isomer Z and -170° and 26° for the isomer E. The increase of environment polarity favors the helical conformation α and the beta-turn like conformation β, but the conformation β2 seems to be still accessible. The (E)-ΔPhe-Ozl residue can be obtained from the isomer Z in photoisomerization reaction. However, hydroxyl-oxazoline-dehydrophenylalanine ΔPhe-Ozn(4-OH) decomposes in such conditions. Alternatively, (E)-ΔPhe-NH2 can be applied as a substrate in the Hantzsch reaction. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 283-294, 2016.

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Section: Introductionmentioning

confidence: 99%

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

et al. 2016

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Michael additions to double bonds of esters of N-protected (s)-phenylalanyldehydroalanine (X-(s)-Phe-ΔAla-OMe) and its phosphonic acid counterpart (X-(s)-Phe-ΔAla-PO(OEt)₂)

Lenartowicz

Dziuk

Zarychta

et al. 2017

Phosphorus, Sulfur, and Silicon and the Related Elements

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Crystal structure ofN-(tert-butoxycarbonyl)glycyl-(Z)-β-bromodehydroalanine methyl ester [Boc–Gly–(β-Br)^(Z)ΔAla–OMe]

Abstract: In a dehydroamino acid with a C=C bond between the α- and β-C atoms, the amino acid residues are linked trans to each other and there are no strong intramolecular hydrogen bonds. The torsion angles indicate a non-helical conformation of the molecule.

Cited by 2 publications

References 17 publications

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

Michael additions to double bonds of esters of N-protected (s)-phenylalanyldehydroalanine (X-(s)-Phe-ΔAla-OMe) and its phosphonic acid counterpart (X-(s)-Phe-ΔAla-PO(OEt)₂)

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Crystal structure ofN-(tert-butoxycarbonyl)glycyl-(Z)-β-bromodehydroalanine methyl ester [Boc–Gly–(β-Br)(Z)ΔAla–OMe]

Abstract: In a de­hydro­amino acid with a C=C bond between the α- and β-C atoms, the amino acid residues are linked trans to each other and there are no strong intra­molecular hydrogen bonds. The torsion angles indicate a non-helical conformation of the mol­ecule.

Cited by 2 publications

References 17 publications

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine

Michael additions to double bonds of esters of N-protected (s)-phenylalanyldehydroalanine (X-(s)-Phe-ΔAla-OMe) and its phosphonic acid counterpart (X-(s)-Phe-ΔAla-PO(OEt)2)

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Crystal structure ofN-(tert-butoxycarbonyl)glycyl-(Z)-β-bromodehydroalanine methyl ester [Boc–Gly–(β-Br)^(Z)ΔAla–OMe]

Abstract: In a dehydroamino acid with a C=C bond between the α- and β-C atoms, the amino acid residues are linked trans to each other and there are no strong intramolecular hydrogen bonds. The torsion angles indicate a non-helical conformation of the molecule.

Michael additions to double bonds of esters of N-protected (s)-phenylalanyldehydroalanine (X-(s)-Phe-ΔAla-OMe) and its phosphonic acid counterpart (X-(s)-Phe-ΔAla-PO(OEt)₂)