Eine Synthese für a,a′-unsubstituierte Pyrrole

Plieninger, Hans; Bühler, Wolfgang

doi:10.1002/ange.19590710415

Cited by 18 publications

(2 citation statements)

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“…Inc. The cis and trans-2-aminocyclopentane-1carboxylic acids were prepared according to procedures reported in the literature (22,23). The l-aminocqclopentane-I-carboxylic acid was purchased from Aldrich.…”

Section: C[malu-phe-d-trp-lys(boc)-thftbu)-gphe J Slowmentioning

confidence: 99%

Cyclic hexapeptide analogs of somatostatin containing bridge modifications

Huang

Pröbstl

Spencer

et al. 1993

International Journal of Peptide and Protein Research

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The cyclic hexapeptide c[Pro6‐Phe7‐D‐Trp8‐Lys9‐Thr10‐Phe11] displays higher bioactivity than native somatostatin in inhibiting the release of growth hormone. The superscript numbers refer to the location of the residues in native somatostatin. To investigate the structural role played by the Phe11‐Pro6 bridging region, we have synthesized a series of cyclic hexapeptide analogs of somatostatin incorporating peptidomimetics and retro‐inverso modifications at the bridging region. Among them, two analogs contain the retro‐inverso modification mAla6‐gPhe11 at the bridging region, and five analogs contain 2‐aminocyclopentane carboxylic acid (2‐Ac5c) and 1‐aminocyclopentane carboxylic acid (1‐Ac2c) as proline mimetics. The conformational preferences of these analogs have been studied using 1H‐NMR and computer simulations. All of these analogs maintain conformations similar to those of the parent cyclic hexapeptide around the Phe7‐D‐Trp8‐Lys9‐Thr10 tetrapeptide region consisting of a β II′ turn. However, they display different conformational features around the bridging region. The R‐mAla analog and the five Ac5c analogs show only a trans amide bond for Phe11‐Pro6 in the bridging region, while the S‐mAla analog displays a cis trans isomerization for the same amide linkage in the bridging region. The R‐mAla and the five Ac5c analogs do not bind to the somatostatin receptor, while the S‐mAla analog displays a high binding activity. Applying our recently proposed model for bioactivity of somatostatin analogs, we examined the structure‐bioactivity relationships for these somatostatin analogs. This investigation provides valuable insight into the structural role played by the bridging region.

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Section: C[malu-phe-d-trp-lys(boc)-thftbu)-gphe J Slowmentioning

confidence: 99%

Cyclic hexapeptide analogs of somatostatin containing bridge modifications

Huang

Pröbstl

Spencer

et al. 1993

International Journal of Peptide and Protein Research

View full text Add to dashboard Cite

show abstract

“…(NC)2CH-CH(CN)2 + H2N-NHR1 frequently than the previous ones. /3-Ketoaldehydes in the form of their acetals were used and 3or 3,4dimethylpyrroles were obtained with 40% yield (333).…”

Section: Nhmentioning

confidence: 99%