- β,γ-Diamino acid: An original building block for hybrid α/γ-peptide synthesis with extra hydrogen bond donating group
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Using a β,γ-diamino acid, several small hybrid α/γ peptides have been synthesized and their conformations investigated through extensive NMR studies and molecular dynamics. A tripeptide and a tetrapeptide have thus shown several hydrogen bonds in solution, including a 13-membered ring involving the β-nitrogen.
- Stanovych, Andrii,Guillot, Rgis,Kouklovsky, Cyrille,Miclet, Emeric,Alezra, Valrie
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p. 2753 - 2757
(2015/02/19)
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- AmIno Acid Homologation by the Blaise Reaction: A new entry into nitrogen heterocycles
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(Chemical Equation Presented) A general strategy for the amino acid homologation via Blaise reaction and subsequent reduction is presented. This strategy involves the preparation of protected α-amino nitriles from the corresponding amino acids, followed by the zinc-mediated condensation of tert-butyl bromoacetate, to give the imidazolidones after iminozincate cyclization. Reduction gave the saturated imidazolidinones with cis or trans stereochemistry, depending on the reduction conditions. This strategy was applied to nonfunctionalized amino acids and to functionalized amino acids such as serine and aspartic acid. Additionally, acidic hydrolysis of cis or trans imidazolidinones to the corresponding chiral 4-aminopyrrolidones is described.
- Cam, Thuy Hoang,Bouillere, Francelin,Johannesen, Sine,Zulauf, Anais,Panel, Cecilia,Pouilhes, Annie,Gori, Didier,Alezra, Valerie,Kouklovsky, Cyrille
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experimental part
p. 4177 - 4187
(2009/09/08)
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- N-urethane-protected amino alkyl isothiocyanates: Synthesis, isolation, characterization, and application to the synthesis of thioureidopeptides
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(Chemical Equation Presented) Synthetically useful N-Fmoc amino-alkyl isothiocyanates have been described, starting from protected amino acids. These compounds have been synthesized in excellent yields by thiocarbonylation of the monoprotected 1,2-diamines with CS2/TEA/p-TsCl, isolated as stable solids, and completely characterized. The procedure has been extended to the synthesis of amino alkyl isothiocyanates from Boc- and Z-protected amino acids as well. The utility of these isothiocyanates for peptidomimetics synthesis has been demonstrated by employing them in the preparation of a series of dithioureidopeptide esters. Boc-Gly-OH and Boc-Phe-OH derived isothiocyanates 9a and 9c have been obtained as single crystals and their structures solved through X-ray diffraction. They belong to the orthorhombic crystal system, and have a single molecule in the asymmetric unit (Z′ = 1). 9a crystallizes in the centrosymmetric space group Pbca, while 9c crystallizes in the noncentrosymmetric space group P212121.
- Sureshbabu, Vommina V.,Naik, Shankar A.,Hemantha,Narendra,Das, Ushati,Guru Row, Tayur N.
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supporting information; experimental part
p. 5260 - 5266
(2009/12/06)
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- A Stereoselective entry into functionalized 1,2-diamines by zinc-mediated homologation of α-aminoacids
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A general, stereoselective synthsis of 4,5-disubstituted imidazolidines-2-ones from α-aminoacids has been developed: the key steps are a Biaise reaction of bromoacetate on α-aminonitriles and further reduction. Although reduction with sodium cyanoborohydride afforded a mixture of cis and trans isomers 6a-e with moderate to good stereoselectivity, reduction with sodium in liquid ammonia gave the trans isomers 8a-e with complete stereoselectivity. Acidic hydrolysis of the urea gave 4-amino-pyrrolidinones, which can be precursors to β,γ-diaminoacids or 3-aminopyrrolidines.
- Hoang, Cam Thuy,Alezra, Valerie,Guillot, Regis,Kouklovsky, Cyrille
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p. 2521 - 2524
(2008/02/05)
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- Microwave-assisted one-pot tandem reactions for direct conversion of primary alcohols and aldehydes to triazines and tetrazoles in aqueous media
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(Chemical Equation Presented) A series of primary alcohols and aldehydes were treated with iodine in ammonia water under microwave irradiation to give the intermediate nitriles, which without isolation underwent [2 + 3] cycloadditions with dicyandiamide and sodium azide to afford high yields of the corresponding triazines and tetrazoles, including the α-amino- and dipeptidyl tetrazoles in high optical purity.
- Shie, Jiun-Jie,Fang, Jim-Min
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p. 3141 - 3144
(2008/02/13)
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- 3,3,3-TRIFLUORO-2-MERCAPTOMETHYL-N-TETRAZOLYL SUBSTITUTED PROPANAMIDES AND METHOD OF USING SAME
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Compounds of the formula STR1 wherein Y can be tetrazolyl are disclosed. These compounds are useful as cardiovascular agents.
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