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1.
Christoph B?ttcher Jan Spengler Samy A. Essawy Klaus Burger 《Monatshefte für Chemie / Chemical Monthly》2004,30(4):853-863
N-Glycosides of Asn and homologues have been synthesized starting from hexafluoroacetone-protected -activated Asp, Glu, and Aad derivatives and glycosylamines. The synthetic value of the new building blocks was demonstrated by the concise incorporation of N-glycosylated Asn, Gln, and Aad -amides into glycopeptides. 相似文献
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Summary. A preparatively simple synthesis of N-linked glycopeptoids starting from iminodiacetic acid and glycosylamines, using hexafluoroacetone as protecting and activating reagent is described. 相似文献
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Christoph B?ttcher Jan Spengler Lothar Hennig Fernando Albericio Klaus Burger 《Monatshefte für Chemie / Chemical Monthly》2005,33(7):577-595
Starting from HFA-protected malic and thiomalic acid a series of O- and N-glycoconjugates suitable for peptide and depsipeptide modification has been synthesized. 相似文献
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Summary.
N-Glycosides of Asn and homologues have been synthesized starting from hexafluoroacetone-protected -activated Asp, Glu, and Aad derivatives and glycosylamines. The synthetic value of the new building blocks was demonstrated by the concise incorporation of N-glycosylated Asn, Gln, and Aad -amides into glycopeptides. 相似文献
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Ksenia Pumpor Elisabeth Windeisen Jan Spengler Fernando Albericio Klaus Burger 《Monatshefte für Chemie / Chemical Monthly》2004,8(2):1427-1443
Hexafluoroacetone reacts with -functionalized ,-dicarboxy acids like aspartic, malic, and thiomalic acid to give exclusively five-membered lactones. The -carboxylic groups remain unaffected and can be derivatized separately. They can be linked i.a. to orthogonal protecting groups or multivalent alcohols like pentaerythritol to give synthetically valuable building blocks. 相似文献
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Ksenia Pumpor Elisabeth Windeisen Jan Spengler Fernando Albericio Klaus Burger 《Monatshefte für Chemie / Chemical Monthly》2004,135(11):1427-1443
Summary. Hexafluoroacetone reacts with -functionalized ,-dicarboxy acids like aspartic, malic, and thiomalic acid to give exclusively five-membered lactones. The -carboxylic groups remain unaffected and can be derivatized separately. They can be linked i.a. to orthogonal protecting groups or multivalent alcohols like pentaerythritol to give synthetically valuable building blocks. 相似文献
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Christoph Böttcher Jan Spengler Klaus Burger 《Monatshefte für Chemie / Chemical Monthly》2004,135(10):1225-1242
Summary. Glycosylated -hydroxy and -mercapto acids have been synthesized starting from malic/citramalic/thiomalic acid and Ac4--D-Glc-NH2/Bzl4--D-Glc-NH2 using hexafluoroacetone as protecting and activating reagent.Dedicated to Prof. Dr. Horst Wilde on the occasion of his 65th birthday 相似文献
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Summary. Starting from HFA-protected malic and thiomalic acid a series of O- and N-glycoconjugates suitable for peptide and depsipeptide modification has been synthesized. 相似文献
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Mohammad Ali Zolfigol Gholamabbas Chehardoli Ezat Ghaemi Elaheh Madrakian Reza Zare Tahereh Azadbakht Khodabakhsh Niknam Shadpour Mallakpour 《Monatshefte für Chemie / Chemical Monthly》2008,121(4):261-265
Various N-bromo reagents [HMTAB, DABCO-bromine, DPTBE, and TBCA] were used as effective oxidizing agents for the oxidation of urazoles and bisurazoles to their corresponding triazolinediones
under mild and heterogeneous conditions at room temperature with good to excellent yields. Also the oxidation of some new
4-phenylurazole derivatives with these reagents is discussed. 相似文献
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a-Bromo benzoylmethylene triphenylphosphorane 3 has been synthesized by the reaction of benzoylmethylene triphenylphosphorane 1 with N-bromosuccinimide in the yield of 87% and can react with aromatic aldehydes 4 to giveα-bromochalcones 5 in good yields. 相似文献
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Klaus Burger Michael Kluge Susanna Fehn Beate Koksch Lothar Hennig Gerhard Müller 《Angewandte Chemie (International ed. in English)》1999,38(10):1414-1416
In only three or four steps glycosylated dipeptide and tripeptide fragments, respectively (see scheme), can be obtained from hydroxy amino acids by using a novel protecting group/activation concept. The method presented is even superior to the pentafluorophenyl ester method. 相似文献
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Monoprotection of symmetrical diketones could be accomplished by using polymeric supported 1,2-diol by monoketalization of only one of the carbonyl groups. These monoprotected diketones could then undergo different types of reactions leading to selective synthesis on one ketone group only. 相似文献
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Thirty-three alkyl and aryl isothiocyanates, as well as isothiocyanate derivatives from esters of coded amino acids and from esters of unnatural amino acids (6-aminocaproic, 4-(aminomethyl)benzoic, and tranexamic acids), were synthesized with satisfactory or very good yields (25–97%). Synthesis was performed in a “one-pot”, two-step procedure, in the presence of organic base (Et3N, DBU or NMM), and carbon disulfide via dithiocarbamates, with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TsO−) as a desulfurization reagent. For the synthesis of aliphatic and aromatic isothiocyanates, reactions were carried out in a microwave reactor, and selected alkyl isothiocyanates were also synthesized in aqueous medium with high yields (72–96%). Isothiocyanate derivatives of L- and D-amino acid methyl esters were synthesized, under conditions without microwave radiation assistance, with low racemization (er 99 > 1), and their absolute configuration was confirmed by circular dichroism. Isothiocyanate derivatives of natural and unnatural amino acids were evaluated for antibacterial activity on E. coli and S. aureus bacterial strains, where the most active was ITC 9e. 相似文献
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A new synthetic approach to elvucitabine started from L-xylose via the reactions of 10 steps in an overall yield of 20% was developed. The key steps included trimethylsilyl trifluoromethanesulfonate(TMSOTf)-mediated stereocontrolled β-glycosidation and exquisite choice of chloroacetyl group for the protection of hydroxyl groups as well as the corresponding deprotection under notably mild conditions. The structure of elvucitabine, in particular, the stereochemistry thereof, was unambiguously determined by comparison of the physical properties, such as 1H NMR data and the specific rotation, of the synthesized sample with those reported. 相似文献