- Photocyclization of Tetra- and Pentapeptides Containing Adamantylphthalimide and Phenylalanines: Reaction Efficiency and Diastereoselectivity
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A series of tetrapeptides and pentapeptides was synthesized bearing a phthalimide chromophore at the N-terminus. The C-terminus of the peptides was strategically substituted with an amino acid, Phe, Phe(OMe), or Phe(OMe)2 characterized by different oxidation potentials. The photochemical reactivity of the peptides was investigated by preparative irradiation and isolation of photoproducts, as well as with laser flash photolysis. Upon photoexcitation, the peptides undergo photoinduced electron transfer (PET) and decarboxylation, followed by diastereoselective cyclization with the retention of configuration for tetrapeptides or inversion of configuration for pentapeptides. Molecular dynamics (MD) simulations and NOE experiments enabled assignment of the stereochemistry of the cyclic peptides. MD simulations of the linear peptides disclosed conformational reasons for the observed diastereoselectivity, being due to the peptide backbone spatial orientation imposed by the Phe amino acids. The photochemical efficiency for the decarboxylation and cyclization is not dependent on the peptide length, but it depends on the oxidation potential of the amino acid at the C-terminus. The results described herein are particularly important for the rational design of efficient photochemical reactions for the preparation of cyclic peptides with the desired selectivity.
- Sohora, Margareta,Vazdar, Mario,Sovi?, Irena,Mlinari?-Majerski, Kata,Basari?, Nikola
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p. 14905 - 14922
(2019/01/04)
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- Nitrogen (oxygen) heterocyclic pentane - 2 - one (thione) compound, pharmaceutical composition, preparation method and use thereof
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The invention belongs to the field of pharmacology, and relates to aza (oxa)-cyclopentane-2- ketone (thione) compounds shown in the formula I, medicine compositions thereof, a preparation method, applications in preparation of medicines treating diabetes and glucolipid metabolism, and especially applications in preparation of medicines treating II-type diabetes.
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Paragraph 0466
(2017/08/25)
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- Synthesis of tetrahydroisoquinoline-based pseudopeptides and their characterization as suitable reverse turn mimetics
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New peptidomimetics containing the Tic moiety were synthesized in enantiomerically pure form and their conformational features were studied by NMR, IR, and molecular modeling techniques. The presence of a reverse turn conformation was observed in all the
- Lesma, Giordano,Meschini, Elisa,Recca, Teresa,Sacchetti, Alessandro,Silvani, Alessandra
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p. 5567 - 5578
(2007/12/30)
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- A new efficient synthetic process for the construction of the pentacyclic core of marine alkaloid ecteinascidins
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The pentacyclic core of ecteinascidins was constructed from two fundamental building blocks, the 1,2,3,4-tetrahydroisoquinoline derivative and the substituted phenylalanine derivative, via 8 steps using readily available L-Dopa as starting material. The k
- Tang, Ye-Feng,Liu, Zhan-Zhu,Chen, Shi-Zhi
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p. 7091 - 7094
(2007/10/03)
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- Novel non-peptide GPIIb/IIIa antagonists: Synthesis and biological activities of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2- oxoethyl)-2-oxopiperazinyl] acetic acids
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To improve the in vitro and in vivo potency of our first low molecular weight GPIIb/IIIa antagonist 1 (TAK-029), a series of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2- oxoethyl)-2-oxopiperazinyl]acetic acids were synthesized th
- Kitamura,Fukushi,Miyawaki,Kawamura,Terashita,Sugihara,Naka
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p. 258 - 267
(2007/10/03)
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- Enantioselective synthesis of pyrrolo[2,1-a]isoquinolones via stereocontrolled N-acyliminium ion cyclisations
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Stereocontrolled N-acyliminium ion cyclisation of L-DOPA derived succinimide 5 has been investigated. Addition of organolithiums to chiral non-racemic 5 yields oxoamides, which are cyclised diastereoselectively upon treatment with BF3·OEt2, to afford 5,10b-trans pyrroloisoquinolones in moderate yields and high ee (99%).
- García, Eva,Arrasate, Sonia,Ardeo, Ainhoa,Lete, Esther,Sotomayor, Nuria
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p. 1511 - 1513
(2007/10/03)
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- Method of increasing lean meat in edible animals
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The present invention discloses substituted 1,3-benzodioxoles which possess anti-diabetic and/or anti-hyperglycemic and/or anti-obesity properties in humans and other animals.
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- Substituted 5-(2-((2-aryl-2-hydroxyethyl)amino)propyl)-1,3-benzodioxoles
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The present invention discloses substituted 1,3-benzodioxoles which possess anti-diabetic and/or anti-hyperglycemic and/or anti-obesity properties in humans and other animals.
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