Design and Synthesis of Chiral .ALPHA.,.ALPHA.-Disubstituted Amino Acids and Conformational Study of Their Oligopeptides

Tanaka, Masakazu

doi:10.1248/cpb.55.349

Cited by 248 publications

(86 citation statements)

References 51 publications

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“…[1][2][3][4][5][6] As a dAA, α-aminoisobutyric acid (Aib) has widely been used to induce helical structures. A right-handed (P) 3 10 -helix is induced in relatively shorter L-amino acid-based peptides having a high Aib content; however, a right-handed (P) α-helix is preferentially formed in relatively longer L-amino acid-based peptides having a low Aib content.…”

Section: Introductionmentioning

confidence: 99%

Helical l–Leu‐Based Peptides Having Chiral Five‐Membered Carbocyclic Ring Amino Acids with an Ethylene Acetal Moiety

et al. 2017

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L-Leu-based heteropeptides having (R)-or (S)-chiral five-membered carbocyclic ring amino acids (Ac 5 c 3EG ) with an ethylene acetal moiety were prepared. A conformational analysis using FT-IR absorption, 1 H NMR, and CD spectra revealed that L-Leu-based hexapeptides and nonapeptides having (R)-or (S)-Ac 5 c 3EG formed right-handed (P) helical structures in solution. An X-ray crystallographic analysis of nonapeptides 5a and 5b showed similar right-handed (P) α-helical structures, without an intramolecular hydrogen bond of the peptide N-H···-O-(acetal) type.

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Section: Introductionmentioning

confidence: 99%

Helical l–Leu‐Based Peptides Having Chiral Five‐Membered Carbocyclic Ring Amino Acids with an Ethylene Acetal Moiety

et al. 2017

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“…The molecule contains an intramolecular hydrogen bond across the macrocycle (N(4)-H···O(2)), which forms a β-turn of type I′ and a second one from N(1)-H to O(2), forming a five-membered loop (C 5 -conformation, see ref. 60 ), which is unusual for an Aib residue 61 . It has to be emphasized that O (2) …”

Section: Synthesis Of the Cyclopentapeptide Cyclo[gly-phe(2me)-aibmentioning

confidence: 99%

Synthesis of Aib-containing cyclopeptides via the ‘azirine/oxazolone method’

Dannecker-Dörig

Linden

Heimgartner

2009

Collect. Czech. Chem. Commun.

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The cyclic pentapeptide cyclo[Gly-Phe(2Me)-Aib-Aib-Gly], containing three α,α-disubstituted α-amino acids, was prepared by cyclization of H-Gly-Phe(2Me)-Aib-Aib-Gly-OH with diphenyl phosporazidate (DPPA) in 60% yield. The synthesis of the linear precursor was performed by using the ‘azirine/oxazolone method’, in which the α,α-disubstituted α-amino acids were introduced by coupling of the corresponding amino or peptide acid with a 2,2-disubstituted 3-amino-2H-azirine. Whereas the cyclization of an analogous hexapeptide afforded the cyclopeptide in 42% yield, the corresponding tetrapeptide yielded a 1:2 mixture of the monomeric and dimeric cyclopeptide. In the case of the tripeptide H-Gly-Phe(2Me)-Aib-OH, the cyclization with DPPA led to the dimeric cyclohexapeptide exclusively.

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“…1,2 In particular, optically active amino acids and their derivatives play a vital role in the design of crucial building blocks required to form peptide and proteins from the twenty naturally occurring proteinogenic L-amino acids. Moreover, non-proteinogenic unnatural amino acids have increasingly become valuable target molecules for drug discovery with expanding synthetic strategies over the last decade.…”

Section: Introductionmentioning

confidence: 99%

“…This helix property promotes the restriction of conformational freedom amongst the amino acid side chains within the peptide structure which allows for resistance towards chemical and enzymatic degradation, increased hydrophobicity and metabolic stability. 2,4 β-Amino acids are another class of compounds that are equally important precursors leading to more complex products with biological and pharmacological activities. 13,14 Moreover β-amino acids are precursors of β-lactams, the most important class of antibiotics.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective synthesis towards unnatural proline based amino acids

Makhathini¹,

Das²,

Singh³

et al. 2016

Arkivoc

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A catalytic diastereoselective Mannich reaction promoted by chiral bifunctional urea-type organocatalysts has been developed. Treatment of N-Boc-3-ketoproline with N-Boc-aldimines under mild conditions afforded the corresponding unnatural proline based amino acid derivatives with excellent diastereoselectivities (up to 99:1) and enantioselectivities (up to 97% ee). The relative configuration of the chiral reaction products was deduced by the comparsion of the experimentally observed ECD spectra to that obtained theorectically.

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Design and Synthesis of Chiral .ALPHA.,.ALPHA.-Disubstituted Amino Acids and Conformational Study of Their Oligopeptides

Cited by 248 publications

References 51 publications

Helical l–Leu‐Based Peptides Having Chiral Five‐Membered Carbocyclic Ring Amino Acids with an Ethylene Acetal Moiety

Helical l–Leu‐Based Peptides Having Chiral Five‐Membered Carbocyclic Ring Amino Acids with an Ethylene Acetal Moiety

Synthesis of Aib-containing cyclopeptides via the ‘azirine/oxazolone method’

Stereoselective synthesis towards unnatural proline based amino acids

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