- Helices with additional H-bonds: crystallographic conformations of α,γ-hybrid peptides helices composed of β-hydroxy γ-amino acids (statines)
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β-Hydroxy-γ-amino acids (Statines) are a class of naturally occurring non-ribosomal amino acids frequently found in many peptide natural products. Peptidomimetics constituted with statines have been used as inhibitors for various aspartic acid proteases. In contrast to the synthetic γ-amino acids, very little is known about the folding behavior of these naturally occurring β-hydroxy γ-amino acids. To understand the folding behavior of statines, three α,γ-hybrid peptides P1 (Ac-Aib-γPhe-Aib-(R, S)Phesta-Aib-γPhe-Aib-CONH2), P2 (Ac-Aib-γPhe-Aib-(S, S)Phesta-Aib-γPhe-Aib-CONH2), and P3 (Ac-Aib-γPhe-Aib-(S, S)Phesta-Aib-(S, S)Phesta-Aib-CONH2) were synthesized on solid phase and their helical conformations in single crystals were studied. Results suggest that both syn and anti diastereoisomers of statines can be accommodated into the helix without deviating overall helical conformation of α,γ-hybrid peptides. In comparison with syn diastereoisomer, the anti diastereoisomer was found to be directly involved in the intramolecular H-bonding with the backbone carbonyl groups (i to i + 3) similar to the backbone amide NHs in the helix.
- Malik, Ankita,Kumar, Mothukuri Ganesh,Bandyopadhyay, Anupam,Gopi, Hosahudya N.
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- Application of the asymmetric aminohydroxylation reaction for the syntheses of HIV-protease inhibitor, hydroxyethylene dipeptide isostere and γ-amino acid derivative
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An enantioselective synthesis of lactone 1, a precursor to the (2R,4S,5S) hydroxyethylene dipeptide isostere and amino acid AHPPA 2 has been accomplished from the common intermediate 5 employing Sharpless asymmetric aminohydroxylation as the key step.
- Kondekar, Nagendra B.,Kandula, Subba Rao V.,Kumar, Pradeep
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p. 5477 - 5479
(2007/10/03)
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- Diastereoselective synthesis of enantiopure γ-amino-β-hydroxy acids by Reformatsky reaction of chiral α-dibenzylamino aldehydes
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N,N-Dibenzylamino aldehydes 1 react with Reformatsky's reagent leading to anti-γ-dibenzylamino-β-hydroxy esters 2 as the major stereoisomers. Treatment of 2 with TFA followed by hydrogenolysis on Pearlman's catalyst yields the corresponding γ-amino-β-hydroxy acids 10. Contrarily, some N-butoxycarbonyl (Boc) amino aldehydes lead to syn-γ-tert-butoxycarbonylamino-β-hydroxy esters as the major product.
- Andrés, José M,Pedrosa, Rafael,Pérez, Alberto,Pérez-Encabo, Alfonso
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p. 8521 - 8530
(2007/10/03)
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- Solid-Phase Synthesis of β-Lactams via the Miller Hydroxamate Approach
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(Matrix Presented) β-Lactams were prepared on solid phase starting from serine, threonine, or other β-hydroxyacids derived from naturally occurring amino acids and a resin bound hydroxylamine. The ring closure was carried out under Mitsunobu conditions. The amino group present on the β-lactam was used to assemble a short peptide. After a reductive cleavage with Sml2, β-lactam-containing peptides were obtained.
- Meloni, Marco Massimiliano,Taddei, Maurizio
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p. 337 - 340
(2007/10/03)
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- Practical asymmetric approach to pyrrolidinones: Efficient synthesis of (+)-preussin and (-)-AHPPA
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A novel, dichloroketene-chiral enol ether cycloaddition-based synthesis of enantiopure (+)-preussin and (-)-AHPPA has been realized. The efficient, highly stereoselective approach, which involves a Beckmann ring expansion reaction to access the key pyrrolidinone, proceeds in ca. 16% overall yield for each of the compounds.
- Kanazawa, Alice,Gillet, Sandra,Delair, Philippe,Greene, Andrew E.
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p. 4660 - 4663
(2007/10/03)
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- Ring opening of optically active cis-disubstituted aziridino alcohols: An enantiodivergent synthesis of functionalized amino alcohol derivatives
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Ring-opening reactions of optically active cis-disubstituted aziridino alcohols have been investigated. Regio- and stereo-selective ring opening took place with internal and external nucleophiles. Unusual amino acids derivatives (14) and (15), the key synthetic intermediates for bestatin and related peptides, have been prepared. n.
- Fuji, Kaoru,Kawabata, Takeo,Kiryu, Yoshimitsu,Sugiura, Yukio
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p. 701 - 722
(2007/10/03)
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- An enantiodivergent synthesis of three β-amino alcohols: Preparation of key intermediates for bestatin and the related peptides
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An enantiodivergent method for preparation of three β-amino alcohols and three 1,2-diamines has been developed starting with a chiral aziridine 1. Unusual amino acid derivatives 3 and 5, which are key synthetic intermediates for bestatin and the related peptides, have been prepared.
- Kawabata,Kiryu,Sugiura,Fuji
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p. 5127 - 5130
(2007/10/02)
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- A stereoselective synthesis of (3S,4S) statine and related compounds
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(3S,4S)Statine and (3S,4S)AHPPA were synthesized efficiently using a highly stereoselective iodocyclocarbamation of the chiral Z-olefins 6 and 6b derived from the correspondent α-aminoacids.
- Misiti,Zappia
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p. 7359 - 7362
(2007/10/02)
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- Synthesis of analogues of the carboxyl protease inhibitor pepstatin. Effect of structure on inhibition of pepsin and renin
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Analogues of the carboxyl protease inhibitor, pepstatin, were synthesized from optically pure forms of N-(tert-butoxycarbonyl)-4-amino-3-hydroxy-6-methylheptanoic acid (Boc-Sta), and the inhibition of pepsin and renin was determined. In addition, the new
- Rich,Sun,Ulm
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