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Beta Amino Acid

The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform

Dieter Seebach – 1st expert on this subject based on the ideXlab platform

  • the proteolytic stability of designed β peptides containing α peptide bond mimics and of mixed α β peptides application to the construction of mhc binding peptides
    Chemistry & Biodiversity, 2005
    Co-Authors: David Hook, Pascal Bindschadler, Yogesh R Mahajan, Radovan Sebesta, Peter Kast, Dieter Seebach

    Abstract:

    Whereas alpha-peptides are rapidly degraded in vivo and in vitro by a multitude of peptidases, substrates constructed entirely of or incorporating homologated alpha-Amino Acid (i.e., BetaAmino Acid) units exhibit a superior stability profile. Efforts made so far to proteolytically hydrolyze a BetaBeta peptide bond have not proved fruitful; a study aimed at breaching this proteolytic stability is discussed here. A series of such bonds have been designed with side-chain groups similar in relative positions (constitution) and three-dimensional arrangements (configuration) as found about alpha-peptidic amide bonds. Increasing the prospect for degradation would permit the tuning of Beta-peptide stability; here, however, no cleavage was observed (1, 2, 4-6, Table 1). Peptides comprised of alpha- and BetaAmino Acids (mixed alpha,Beta-peptides, 8-11) are expected to benefit from both recognition by a natural receptor and a high level of proteolytic stability, ideal characteristics of pharmacologically active compounds. Beta3-peptides containing alpha-Amino Acid moieties at the N-terminus are degraded, albeit slowly, by several peptidases. Of particular interest is the ability of pronase to cleave an alpha-Beta peptide bond, namely that of alphaAla-Beta3 hAla. Significantly, successful hydrolysis is independent of the configuration of the BetaAmino Acid. Some of the alpha,Beta-peptides discussed here are being investigated for their binding affinities to class I MHC proteins. The computer-programming steps required to prepare alpha,Beta-peptides on an automated peptide synthesizer are presented.

  • The Proteolytic Stability of ‘Designed’ β‐Peptides Containing α‐Peptide‐Bond Mimics and of Mixed α,β‐Peptides: Application to the Construction of MHC‐Binding Peptides
    Chemistry & Biodiversity, 2005
    Co-Authors: David Hook, Pascal Bindschadler, Yogesh R Mahajan, Radovan Sebesta, Peter Kast, Dieter Seebach

    Abstract:

    Whereas alpha-peptides are rapidly degraded in vivo and in vitro by a multitude of peptidases, substrates constructed entirely of or incorporating homologated alpha-Amino Acid (i.e., BetaAmino Acid) units exhibit a superior stability profile. Efforts made so far to proteolytically hydrolyze a BetaBeta peptide bond have not proved fruitful; a study aimed at breaching this proteolytic stability is discussed here. A series of such bonds have been designed with side-chain groups similar in relative positions (constitution) and three-dimensional arrangements (configuration) as found about alpha-peptidic amide bonds. Increasing the prospect for degradation would permit the tuning of Beta-peptide stability; here, however, no cleavage was observed (1, 2, 4-6, Table 1). Peptides comprised of alpha- and BetaAmino Acids (mixed alpha,Beta-peptides, 8-11) are expected to benefit from both recognition by a natural receptor and a high level of proteolytic stability, ideal characteristics of pharmacologically active compounds. Beta3-peptides containing alpha-Amino Acid moieties at the N-terminus are degraded, albeit slowly, by several peptidases. Of particular interest is the ability of pronase to cleave an alpha-Beta peptide bond, namely that of alphaAla-Beta3 hAla. Significantly, successful hydrolysis is independent of the configuration of the BetaAmino Acid. Some of the alpha,Beta-peptides discussed here are being investigated for their binding affinities to class I MHC proteins. The computer-programming steps required to prepare alpha,Beta-peptides on an automated peptide synthesizer are presented.

  • Synthesis and biological evaluation of a cyclo-β-tetrapeptide as a somatostatin analogue
    Angewandte Chemie, 1999
    Co-Authors: Karl Gademann, Martin Ernst, Daniel Hoyer, Dieter Seebach

    Abstract:

    Cyclo-Beta-tetrapeptide I, a Beta-peptidic analog of octreotide, was prepd. from BetaAmino Acid building blocks synthesized by Arndt-Eistert homologation of appropriately protected alpha-Amino Acids. The affinity of I for five different human somatostatin receptors was measured using radioligand-binding assays. I had affinity, although the concns. were in the micromolar and not in the nanomolar range as for somatostatin and octreotide. The authors have demonstrated that a small Beta-peptide (consisting of only four BetaAmino Acids) can mimic a natural peptide hormone and display biol. activity and micromolar affinity for human receptors. Thus, Beta-peptides can, in principle, be considered as peptidomimetics.

Mukund P Sibi – 2nd expert on this subject based on the ideXlab platform

  • n benzylhydroxylamine addition to Beta aryl enoates enantioselective synthesis of Beta aryl Beta Amino Acid precursors
    Organic Letters, 2000
    Co-Authors: Mukund P Sibi

    Abstract:

    Chiral Lewis Acid catalyzed N-benzylhydroxylamine addition to pyrrolidinone-derived enoates afforded β-aryl-β-Amino Acid derivatives in high enantiomeric purity with moderate to very good chemical efficiency.

Jackie Y Ying – 3rd expert on this subject based on the ideXlab platform

  • organocatalytic synthesis of n phenylisoxazolidin 5 ones and a one pot synthesis of Beta Amino Acid esters
    Organic Letters, 2008
    Co-Authors: Jayasree Seayad, Pranab K Patra, Yugen Zhang, Jackie Y Ying

    Abstract:

    A novel N-heterocyclic carbene (NHC)-catalyzed C−N bond formation by the reaction of α,β-unsaturated aldehydes and nitrosobenzene to N-phenylisoxazolidin-5-ones, followed by an Acid-catalyzed esterification and Bamberger-like rearrangement in a mild one-pot protocol leads to N-p-methoxyphenyl (N-PMP) protected β-Amino Acid esters.