Conformational investigation of α,β‐dehydropeptides Part VI. Molecular and crystal structure of benzyloxycarbonylglycyl‐(<i>Z</i>)‐dehydrophenylalanine

The Fourier transform infrared spectra are analyzed in the regions of vs(N‐H), amide I, amide II and vs(Cα=Cβ) bands for a series of Ac‐ΔXaa‐NHMe, where ΔXaa =ΔAla, (Z)‐ΔAbu, (Z)‐ΔLeu, (Z)‐ΔPhe and AVal, to determine the predominant solution conformation of these α, β‐dehydropeptide‐related molecules and the electron distribution perturbation in their amide bonds. The measurements were performed in dichloromethane (DCM). To confirm and rationalize the assignments, the spectra of the respective series of saturated Ac‐Xaa‐NHMe, recorded in DCM, and the spectra of these two series of unsaturated and saturated compounds, recorded in acetonitrile, were examined. To help interpret the spectroscopic results, the equilibrium geometrical parameters for some selected amides were used. These were optimized with ab initio methods in the 6‐31G** basis set. Each of the dehydroamides studied adopted a C5 structure, which in Ac‐ΔAla‐NHMe is fully extended and accompanied by the strong C5 hydrogen bond. Interaction with the Cα=Cβ bond lessened the amidic resonance within each of the flanking amide groups. The N‐terminal C=O bond was noticeably shorter, both amide bonds were longer than the corresponding bonds in the saturated entities and the N‐terminal amide system was distorted. Ac‐ΔAla‐NHMe constituted an exception. Its C‐terminal amide bond was shorter than the standard one and both amide systems were prototypically planar.

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“…The significant amide departure from planarity is often observed in dehydropeptide crystal structures (e.g. [53][54][55][56].…”

Section: Perturbation Of the Electron Distribution In The Amide Systementioning

confidence: 99%

Conformational investigation of α, β‐dehydropeptides. VIII.*N‐Acetyl‐α, β‐dehydroamino acid N'‐methylamides: conformation and electron density perturbation from infrared and theoretical studies

Broda

Rzeszotarska

Smelka

et al. 1997

The Journal of Peptide Research

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“…As in the case of the aforementioned Aib peptides discussed, many ΔPhe‐containing linear peptides are highly crystalline materials. This property allows X‐ray diffraction analyses to be performed . Almost all of them are characterized by the Δ Z Phe configurational isomer.…”

Section: Cαβ‐didehydro‐α‐amino Acid‐containing Peptidesmentioning

confidence: 99%

Handedness preference and switching of peptide helices. Part II: Helices based on noncodedα‐amino acids

Crisma¹,

Zotti

Formaggio

et al. 2015

Journal of Peptide Science

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In this second part of our review article on the preferred screw sense and interconversion of peptide helices, we discuss the most significant computational and experimental data published on helices formed by the most extensively investigated categories of noncoded α-amino acids. They are as follows: (i) N-alkylated Gly residues (peptoids), (ii) C(α) -alkylated α-amino acids, (iii) C(α,β) -sp(2) configurated α-amino acids, and (iv) combinations of residues of types (ii) and (iii). With confidence, the large body of interesting papers examined and classified in this editorial effort will stimulate the development of helical peptides in many diverse areas of biosciences and nanosciences.

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Simultaneous formation of isoquinoline and 1-azetine derivatives via photoacetyl migration of substituted α-dehydrophenylalanine

Kubo

Yaegashi

Sasaki

et al. 1996

Tetrahedron Letters

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Conformational investigation of α,β‐dehydropeptides Part VI. Molecular and crystal structure of benzyloxycarbonylglycyl‐(Z)‐dehydrophenylalanine

Cited by 20 publications

References 45 publications

Conformational investigation of α, β‐dehydropeptides. VIII.*N‐Acetyl‐α, β‐dehydroamino acid N'‐methylamides: conformation and electron density perturbation from infrared and theoretical studies

Conformational investigation of α, β‐dehydropeptides. VIII.*N‐Acetyl‐α, β‐dehydroamino acid N'‐methylamides: conformation and electron density perturbation from infrared and theoretical studies

Handedness preference and switching of peptide helices. Part II: Helices based on noncodedα‐amino acids

Simultaneous formation of isoquinoline and 1-azetine derivatives via photoacetyl migration of substituted α-dehydrophenylalanine

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