Synthesis of novel proline–thiazole based cyclic hexa- and octapeptides

Jayaprakash, Sarva; Pattenden, Gerald; Viljoen, Murray S.; Wilson, Claire

doi:10.1016/s0040-4020(03)00992-x

Cited by 17 publications

(5 citation statements)

References 25 publications

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“…The cyclooligomerisations of amino acid-based thiazoles is clearly a useful synthetic route to libraries of novel, non-natural cyclic peptides. Indeed, the scope for the method has also been demonstrated with proline 35 and N-methylvaline thiazole 36 amino acids, i.e. 54 and 57, leading to similar cyclic trimers, viz.…”

Section: Conformational Studies With Cyclic Peptidesmentioning

confidence: 99%

Marine metabolites: metal binding and metal complexes of azole-based cyclic peptides of marine origin

Bertram

Pattenden

2007

Nat. Prod. Rep.

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Azole-based cyclic peptides found in ascidians ("sea squirts") of the genus Lissoclinum have a high propensity to chelate metal ions. This Highlight summarises the current evidence for marine cyclic peptide-metal congruence, and the structural and stereochemical features in cyclic peptides which seem necessary to facilitate metal complexation. The biological relevance of the metal ions in these associations, including their possible role in the assembly of cyclic peptides in the marine milieu, is also briefly considered. Finally, the synthesis of natural, and some novel non-natural, azole-based cyclic peptides from the cyclooligomerisation and assembly of azole-based amino acids, including in the presence of metal ions, is presented.

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Section: Conformational Studies With Cyclic Peptidesmentioning

confidence: 99%

Marine metabolites: metal binding and metal complexes of azole-based cyclic peptides of marine origin

Bertram

Pattenden

2007

Nat. Prod. Rep.

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“…A second PyBOP-mediated reaction successfully coupled the left-hand bis(thiazole) 35 to provide the cyclization precursor 44. The terminal N-Boc and tert-butyl ester groups in 44 were simultaneously cleaved using TFA, and the resulting amino acid treated with diphenylphosphoryl azide (DPPA) [66][67][68][69] and Hu ¨nig's base in DMF. This resulted in macrolactamization in a yield of 73% (from 44) to give amythiamicin D 8 (Scheme 10).…”

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confidence: 99%

Total Synthesis of the Thiopeptide Antibiotic Amythiamicin D

et al. 2005

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The thiopeptide (or thiostrepton) antibiotics are a class of sulfur containing highly modified cyclic peptides with interesting biological properties, including reported activity against MRSA and malaria. Described herein is the total synthesis of the thiopeptide natural product amythiamicin D, which utilizes a biosynthesis-inspired hetero-Diels-Alder route to the pyridine core of the antibiotic as a key step. Preliminary studies using a range of serine-derived 1-ethoxy-2-azadienes established that hetero-Diels-Alder reaction with N-acetylenamines proceeded efficiently under microwave irradiation to give 2,3,6-trisubstituted pyridines. The thiazole building blocks of the antibiotic were obtained by either classical Hantzsch reactions or by dirhodium(II)-catalyzed chemoselective carbene N-H insertion followed by thionation, and were combined to give the bis-thiazole that forms the left-hand fragment of the antibiotic. The key Diels-Alder reaction of a tris-thiazolyl azadiene with benzyl 2-(1-acetylaminoethenyl)thiazole-4-carboxylate gave the core tetrathiazolyl pyridine, which was elaborated into the natural product by successive incorporation of glycine and bis-thiazole fragments followed by macrocyclization.

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“…Our use of this approach complements substantial prior work by others who used an MCO strategy to prepare oligomeric esters and amides. Most notable is the use of activated seco -acids to form macrodiolides (and triolides) − and amidations of activated peptidic amino acids to construct the macrocyclic peptides valinomycin and westiellamide. − A common feature to these amidation reactions is a five-membered heterocycle, such as a thiazole or oxazole, installed in the peptide backbone. − This presumably enhances a conformation more favorable for cyclization.…”

Section: Results and Discussionmentioning

confidence: 99%

The Formation of Impossible Rings in Macrocyclooligomerizations for Cyclodepsipeptide Synthesis: The 18-from-12 Paradox

Smith

Johnston

2021

J. Org. Chem.

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A reinvestigation into the macrocyclooligomerization (MCO) of a tetradepsipeptide is reported, uncovering a paradox in which the MCO of depsipeptide monomers can produce “impossible” ring sizes: a 12-atom chain produced the expected 24-membered ring, alongside unexpected 18- and 30-membered cyclic oligomeric depsipeptides (CODs). We report an alternative preparation of authentic 18- and 36-membered macrocycles for this case using a stepwise synthesis that provides definitive analytical characterization for each ring size. Our investigation yields a recharacterization and reassignment of two macrocycles originally reported in this MCO series, along with updated yields and isothermal titration calorimetry data after implementation of new critical protocols for purification and subsequent analysis. Initial studies to probe this mechanistic conundrum are described.

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Synthesis of novel proline–thiazole based cyclic hexa- and octapeptides

Cited by 17 publications

References 25 publications

Marine metabolites: metal binding and metal complexes of azole-based cyclic peptides of marine origin

Marine metabolites: metal binding and metal complexes of azole-based cyclic peptides of marine origin

Total Synthesis of the Thiopeptide Antibiotic Amythiamicin D

The Formation of Impossible Rings in Macrocyclooligomerizations for Cyclodepsipeptide Synthesis: The 18-from-12 Paradox

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