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  • 1
    Electronic Resource
    Electronic Resource
    Konformationsanalyse, III. exo-Anomerer Effekt und Circulardichroismus von Glycopyranosylaziden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1568-1578 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational Analysis, III. exo-Anomeric Effect and Circular Dichroism of Glycopyranosyl AzidesTetra-O-acetyl-aldopentopyranoses and penta-O-acetyl-aldohexopyranoses react readily with trimethylsilyl azide in the presence of BF3 or SnCl4 to afford the corresponding glycosyl azides 1a - 11 (table 1). Only the anomeric glycosyl azide having the azido group „trans“ to the 2-acetoxy group is obtained in each case. The polarization of the Cl—Nx and Nx—Nz bonds in glycosyl azides is such that in both cases the dipole is directed toward Nx. It can be deduced that glycosyl azides, like methyl glycopyranosides, should exhibit an exo-anomeric effect which strongly favors the conformers 9 and 12. The application of the azide-octant rule predicts a negative Cotton effect for the α-D-glycosyl azide 12 and a positive effect for the β-D-glycosyl azide 9. Circular dichroism measurements are in good agreement with these predictions, indicating the operation of an exo-anomeric effect in the glycosyl azides.
    Notes: Tetra-O-acetyl-pentopyranosen und Penta-O-acetyl-hexopyranosen setzen sich mit Trimethylsilylazid bei Gegenwart von BF3 oder SnCl4 leicht zu den entsprechenden Glycosylaziden 1a bis 11 um (Tab. 1). Es entsteht stets nur das anomere Glycosylazid, in dem die Azidogruppe und 2-OAc „trans“ zueinander angeordnet sind. In Glycosylaziden sind die Bindungen Cl—Nx und Nx—Nz in der Weise polarisiert, daß der Dipol in beiden Fällen zum Nx weist. Hieraus wird abgeleitet, daß bei Glycosylaziden wie bei Methylglycosiden ein exo-anomerer Effekt wirksam sein sollte, der die Konformeren 9 und 12 stark bevorzugt. Die Anwendung der Azid-Oktantenregel sagt für das α-D-Glycosylazid 12 einen negativen, für das β-D-Glycosylazid 9 einen positiven Cotton-Effekt voraus. Messungen des Circular-dichroismus stimmen mit diesen Voraussagen gut überein, was für einen exo-anomeren Effekt bei Glycosylaziden spricht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070517
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  • 2
    Electronic Resource
    Electronic Resource
    Analogues of Sialic Acids as Potential Sialidase Inhibitors. Synthesis of C6 and C7 Analogues of N-Acetyl-6-amino-2,6-dideoxyneuraminic Acid (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 343-369 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The piperidines 12-18, piperidmose analogues of Neu5Ac (1) with a shortened side chain, were synthesized from N-acetyl-D-glucosamine via the azidoalkene 32 and tested as inhibitors of Vibrio cholerae sialidase. Deoxygenation at C(4) of the uronate 22, obtained from the known D-GlcNAc derivative 20, was effected by β-elimination (→ 23), exchange of the AcO at C(3) with a (t-Bu)Me2SiO group and hydrogenation (→ 26; Scheme 1). Chain extension of 26 by reaction with Me3SiCH2MgCl gave the D-ido-dihydroxysilane 28, which was transformed into the unsaturated L-xylo-mesylate 29 and further into the L-lyxo-alcohol 30, the mesylate 31, and the L-xylo-azide 32. The derivatives 29-31 prefer a sickle zig-zag and 32 mainly an extended zig-zag conformation (Fig. 2). The piperidinecarboxylate 15 was obtained from 32 by ozonolysis (→ 33), intramolecular reductive animation (→ 34), and deprotection, while reductive animation of 34 with glycolaldehyde (→ 35) and deprotection gave 16 (Scheme 2). An intramolecular azide-olefin cycloaddition of 32 yielded exclusively the fused dihydrotriazole 36, while the lactone 39 did not cyclize (Scheme 3). Treatment of 36 with AcOH (→ 37) followed by hydrolysis (→ 38) and deprotection led to the amino acid 18. To prepare the (hydroxymethyl)piperidinecarboxylates 12 and 17, 32 was first dihydroxylated (Scheme 4). The L-gluco-diol 40 was obtained as the major product, in agreement with Kishi's rule. Silylation of 40 (→ 42), oxidation with periodinane (→ 44), and reductive animation gave the L-gluco-piperidine 45. It was, on the one hand, deprotected to the amino acid 12 and, on the other hand, N-phenylated (→ 46) and deprotected to 17. While 45 and 12 adopt a 2C5 conformation, the analogous N-Ph derivatives 46 and 17 adopt a 5C2 and a B3,6 conformation, respectively, on account of the allylic 1,3-strain. The conformational effects of this 1,3-strain are also evident in the carbamate 47, obtained from 45 (Scheme 5), and in the C(2)-epimerized bicyclic ether 48, which was formed upon treatment of 47 with (diethylamino)sulfur trifluoride (DAST). Fluorination of 40 with DAST (→ 49) followed by treatment with AcOH led to the D-ido-fluorohydrin 50. Oxidation of 50 (→ 51) followed by a Staudinger reaction and reduction with NaBH3CN afforded the (fluoromethyl)piperidine 52, while reductive amination of 51 with H2/Pd led to the methylpiperidine 55, which was similarly obtained from the keto tosylate 54 and from the dihydrotriazole 36. Deprotection of 52 and 55 gave the amino acids 13 and 14, respectively. The aniline 17 does not inhibit V. cholerae sialidase; the piperidines 12-16 and 18 are weak inhibitors, evidencing the importance of an intact 1,2,3-trihydroxypropyl side chain.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740214
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  • 3
    Electronic Resource
    Electronic Resource
    Diastereo- and Regioisomeric Bicyclic Thiohydantions from Chiral 1,3-Thiazolidine-2,4-dicarboxylic acids (1998)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 81 (1998), S. 744-753 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bicyclic thiohydantoins were synthesized in a stereoselective manner by reacting (2R)/(2S)-diastereoisomer mixtures of 1,3-thiazolidine-2,4-dicarboxylic acids or their dimethyl diesters with PhNCS. 5,5-Dimethyl-1,3-thiazolidine-2,4-dicarboxylic acid with PhNCS led to a cyclization involving the C=O group at the C(2) center of the thiazolidine ring, while the acid's dimethyl diester gave cyclization involving the C=O group at C(4). In contrast, reactions involving unsubstituted 1,3-thiazolidine-2,4-dicarboxylic acid or its dimethyl diester led to thiohydantoins in which the ring closure had taken place only with the COO group at C(4). Independently of the direction of the ring closure, all reactions produce exclusively products with the (R)-configuration at C(2). The configurational assignments were based on 1H- and 13C-NMR studies, and confirmed by X-ray crystallographic analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19980810324
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  • 4
    Electronic Resource
    Electronic Resource
    Konformationsanalyse, V. Einfluß des anomeren und inversen anomeren Effektes auf Konformationsgleichgewichte von N-substituierten N-Pentopyranosiden (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1590-1613 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational Analysis, V. Influence of the Anomeric and Reverse Anomeric Effect on Conformational Equilibria of a N-Substituted N-PentopyranosidesThe conformational equilibria of N-substituted N-pentopyranosides have been investigated. The anomeric effect decreases with substitution at C-1 by the following groups in the order: \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \ominus - \mathop {\rm P}\limits^ \oplus ({\rm C}_6 {\rm H}_5)_3 $\end{document} 〉 OAc 〉 N3 〉 NHCOCF3 〉 NHCOC6H4OCH3-(p) ≃ NHCOC6H4NO2-(p) 〉 NH2 ≃ NHAc ≃ \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \oplus {\rm PH} $\end{document}(C6H5)3]Cl⊖ 〉 imidazolium salt ≃ pyridinium salt. Neither an anomeric effect nor a reverse anomeric effect was detectable with the NH2-group. The imidazolium and pyridinium compounds 33 and 31 show a reverse anomeric effect, whereby in the α-D-xylo-series inversion to the triaxial 1C4(D) conformation takes place. a predominant influence on the anomeric effect is attributes to the C1—N1 dipole. The substituent with a negatively charged nitrogen \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \ominus - \mathop {\rm P}\limits^ \oplus ({\rm C}_6 {\rm H}_5)_3 $\end{document} shows the largest anomeric effect, which completely disappears upon protonation of the ylid to \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \oplus {\rm PH} $\end{document}(C6H5)3]Cl⊖.
    Notes: Konformationsgleichgewichte von N-substituierten N-Pentopyranosiden wurden untersucht. Der anomere Effekt nimmt bei Substitution am C-1 durch nachstehende Gruppen in folgender Reihe ab: \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \ominus - \mathop {\rm P}\limits^ \oplus ({\rm C}_6 {\rm H}_5)_3 $\end{document} 〉 OAc 〉 N3 〉 NHCOCF3 〉 NHCOC6H4OCH3-(p) ≃ NHCO- C6H4NO2-(p) 〉 NH2 ≃ NHAc ≃ \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \oplus {\rm PH} $\end{document}(C6H5)3]Cl⊖ 〉 Imidazoliumsalz ≃ Pyridiniumsalz. Bei der NH2-Gruppe ist kein anomerer und inverser anomerer Effekt nachweisbar. Die Imidazolium- und Pyridinium-Verbindungen 33 und 31 zeigen inversen anomeren Effekt, wodurch in der α-D-xylo-Reihe Inversion zur triaxialen 1C4(D)-Konformation eintritt. Dem C1—N1-Dipol wird ein überwiegender Einfluß auf den anomeren Effekt zugemessen. Der Substituent mit negativiertem Stickstoff \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \ominus - \mathop {\rm P}\limits^ \oplus ({\rm C}_6 {\rm H}_5)_3 $\end{document} weist den größten anomeren Effekt auf, der bei Protonierung des Ylids zur \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^ \oplus {\rm PH} $\end{document}(C6H5)3]Cl⊖-Gruppe vollständig verschwindet.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070519
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  • 5
    Electronic Resource
    Electronic Resource
    Heterocyclische Verbindungen aus Zuckern, XI. Ringschlußreaktion von D-Penicillamin mit 2,3,4,5-Tetra-O-acetyl-aldehyde-L-arabinose; 13C-NMR-Spektren von 2-Poly-acetoxyalkylthiazolidin-4-carbonsäurederivaten (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 701-707 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic Compounds from Sugars, XI1). - Cyclisation of D-Penicillamine with 2,3,4,5-Tetra-O-acetyl-aldehydo-L-arabinose; “C-NMR Spectra of 2-Polyacetoxyalkylthiazolidine-4-carboxylic Acid Derivatives5,5-Dimethyl-2(S)- und 5,5-dimethyl-2(R)-(L-arabino-1',2',3',4' -tetraacetoxybutyl)thiazolidine-4-(S)-carboxylic acids (3 and 4) were obtained by condensation of D-penicillamine (1) with 2,3,4,5-tetra-O-acetyl-aldehydo-L-arabinose (2). The structures of 3 and 4 were ascertained using chemical reactions and 1H-NMR spectroscopy. 13C chemical shift data for the methyl esters (5 and 6) of 3 and 4, for the N-acetyl derivatives (11 and 13) of 5 and 6 and of other 2-polyacetoxyalkylthiazo-lidine-4-carboxylic acids are reported.
    Notes: Die Kondensation von D-Penicillamin (1) mit 2,3,4,5-Tetra-O-acetyl-aldehydo-L-arabinose (2) er-gibt 5,5-Dimethyl-2(S)- und 5,5-Dimethyl-2(R)-(L-arabino-1',2',3',4' -tetraacetoxybutyl)thiazolidine-4(S)-carbonsäure (3 bzw. 4), deren Strukturen auf chemischem Wege und durch 1H-NMR-Spektroskopie bewiesen werden. Die 13C-NMR-Spektren der Methylester (5 bzw. 6) von 3 und 4, der N-Acetylderivate (11 bzw. 13) von 5 und 6 sowie bereits beschriebener 2-Polyacetoxyalkyl-thiazolidin-4-carbonsäuren werden mitgeteilt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790513
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  • 6
    Electronic Resource
    Electronic Resource
    Darstellung und Konformation der 1,2-cis-Pentopyranosylazide (1986)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 1393-1397 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Conformation of 1,2-cis-Pentopyranosyl AzidesReaction of acetylated 1,2-trans-pentopyranosyl halides 1a, b, 2, 3 with NaN3 in HMPT under mild condition yielded all the four 1,2-cis-2,3,4-tri-O-acetylpentopyranosyl azides 4, 6, 8, and 14 which, on deacetylation, gave the free azides 5, 7, 9, and 15. Solution conformations, based on vicinal proton-proton coupling constants, are discussed in terms of 4C1(D)⇌1C4(D) equilibria and comparisons are made with other pyranose derivatives.
    Notes: Die Umsetzung der acetylierten 1,2-trans-Pentopyranosylhalogenide 1a, b, 2, 3 mit NaN3 in HMPT unter milden Bedingungen ergibt die 4 möglichen 1,2-cis-2,3,4-Tri-O-acetylpentopyranosylazide 4, 6, 8 und 14, die durch Entacetylierung in die freien Azide 5, 7, 9 und 15 übergeführt werden. Anhand der vicinalen Proton-Proton-Kopplungskonstanten werden die 4C1(D)⇌1C4(D)-Konformationsgleichgewichte in Lösung diskutiert und mit verwandten Pyranosederivaten verglichen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198619860810
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  • 7
    Electronic Resource
    Electronic Resource
    Einfache Synthesen der anomeren, an C-6 modifizierten Galacto- und Glucopyranosylazide (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 235-241 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Facile Syntheses of Galacto- and Glucopyranosyl Azides Substituted at C-6Acetylated 6-chloro-, 6-bromo-, 6-iodo-, and 6-azido-6-deoxy-α-D-glucopyranosyl azides (26, 22, 17, 30), -β-D-glucopyranosyl azides (27, 23, 18, 31), -α-D-galactopyranosyl azides (29, 25, 20, 32), and -β-D-galactopyranosyl azides (29, 25, 20, 33) have been obtained by nucleophilic displacement reactions of the appropriate 6-O-(p-toluenesulfonates) 9-12. Hydrogen iodide elimimation from the 6-iodo-6-deoxyglycosyl azides 17-20 by DBU or DBN leads to the hex-5-enopyranosyl azides with α-D-xylo (43), β-D-xylo (44), α-L-arabino (46), and β-L-arabino configuration. The structures, anomeric configurations, and conformations of the products were determined by 1H-NMR spectroscopy.
    Notes: Acetylierte 6-Chlor-, 6-Brom-, 6-Iod- und 6-Azido-6-desoxy-Derivate des α-D-Glucopyranosylazids (26, 22, 17, 30) und β-D-Glucopyranosylazids (27, 23, 18, 31) sowie des α-D-Galactopyranosylazids (28, 24, 19, 32) und β-D-Galactopyranosylazids (29, 25, 20, 33) wurden durch nucleophile Substitutionsreaktionen der entsprechenden 6-O-(p-Toluolsulfonate) 9-12 gewonnen. Die Dehdroiodierung der 6-Iod-6-desoxyazide 17-20 mit DBU oder DBN führte zu den Hex-5-enopyranosylaziden mit α-D-xylo- (43) und β-D-xylo- (44), sowie α-L-arabino- (46) und β-L-arabino-Konfiguration (45). Die Strukturen, die anomeren Konfigurationen und die Konformationen der Produkte werden durch 1H-NMR-Spektroskopie bestimmt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870314
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  • 8
    Electronic Resource
    Electronic Resource
    Synthese und chiroptische Eigenschaften von N-Acetyl-2-aryl-4-thiazolidincarbonsäuren (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 927-934 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Chiroptical Properties of N-Acetyl-2-aryl-4-thiazolidinecarboxylic Acids(4R)-2-Aryl-4-thiazolidinecarboxylic acids 3, derived from aromatic aldehydes 1 and L-cysteine (2), could be diastereoselectively converted into (1R,4R)- or (2S,4R)-N-acetyl-2-aryl-4-thiazolidinecarboxylic acids (4 and 5, resp.). The diastereomers can be differentiated on the basis of their chiroptical properties. The correlation between CD spectra and the conformation of the molecules is discussed.
    Notes: Die aus aromatischen Aldehyden 1 und L-Cystein (2) in wäßrigem Methanol in sehr guten Ausbeuten entstehenden (4R)-2-Aryl-4-thiazolidincarbonsäuren 3 können diastereoselektiv zu den (2R,4R)- oder den (2S,4R)-N-Acetyl-2-aryl-4-thiazolidincarbonsäuren 4 bzw. 5 umgesetzt werden. Die Unterscheidung der Diastereomeren 4 und 5 erfolgt auf Grund ihrer chiroptischen Eigenschaften. Der Zusammenhang zwischen CD-Spektren und der Konformation der Moleküle wird diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870850
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  • 9
    Electronic Resource
    Electronic Resource
    Darstellung und Charakterisierung von diastereomeren (4S)-3-Acetyl-2-aryl-5,5-dimethyl-4-thiazolidincarbonsäuren (1990)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 281-286 
    Details
    ISSN: 0170-2041
    Keywords: Thiazolidine, 4-carboxylic acid ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Characterisation of Diastereomeric (4S)-3-Acetyl-2-aryl-5,5-dimethyl-4-thiazolidinecarboxylic AcidsThe condensation of aromatic aldehydes 1 and D-penicillamine (2) in aqueous methanol gives (4S)-2-aryl-5,5-dimethyl-4-thiazolidinecarboxylic acids 3 with alternating diastereoselectivity in position 2. Acetylation of the products with acetic anhydride in pyridine or in water gives rise to (2S,4S)-3-acetyl-2-aryl-5,5-dimethyl-4-thiazolidinecarboxylic acids 5. Use of a HCl/dioxane system in the reaction of N-acetyl-D-penicillamine (6) with aldehydes made possible the effective preparation of (2R,4S) compounds 8. The diastereomeric compounds 5 and 8 were characterized by 1H- and 13C-NMR data and optical rotation and CD. The results were compared with those compiled from the already synthesized diastereomeric (4R)-3-acetyl-2-aryl-4-thiazolidinecarboxylic acids.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199019900151
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  • 10
    Electronic Resource
    Electronic Resource
    Darstellung der anomeren 2-O-Methyl-α- und -β-pyranosylazide (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 279-289 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Anomeric 2-o-Methyl-α-pyranosyl AzidesThe synthesis of 3,4,6-tri-O-acetyl-2-O-methyl-β-D-glucopyranosyl- and -galactopyranosyl azide 1 and 10, respectively, was accomplished using the levulinoyl-protected intermediates 4 and 7. With hydrazine acetate 4 and 7 yield the key compounds 2 and 8 with free 2-OH group which could be methylated to give 1 and 10. The corresponding α-pyranosyl azides 18 and 19 are accessible by conversion of 1,3,4,6-tetra-O-methylpyranoses 16 and 17, respectively, with trimethylsilyl azide using a Lewis acid catalyst. 3,4-Di-O-methyl-α-L-arabino-pyranosyl azide (11) as well as 3,4-O-isopropylidene-2-O-methyl-α-L-ribopyranosyl azide (26) can be obtained from α-L-arabinopyranosyl azide (12)
    Notes: Die Synthese des 3,4,6-Tri-O-acetyl-2-O-methyl-β-D-glucopyranosyl- und -galactopyranosylazids (1) und (10) wurde aus den in 2-Stellung mit einem Lävulinoylrest geschützten Aziden 4 und 7 verwirklicht. Aus 4 und 7 sind die Verbindungen mit freier 2-OH-Gruppe 2 und 8 mit Hydrazinacetat darstellbar, die sich zu 1 und 10 methylieren lassen. Die entsprechenden α-Pyranosylazide 18 und 19 sind durch Umsetzung der 1,3,4,6-Tetra-O-acetyl-2-O-methylpyranosen 16 und 17 mit Trimethylsilylazid unter Lewis-Säure-Katalyse zugänglich. Aus α-L-Arabinopyranosylazid (12) kann sowohl das 3,4-Di-O-acetyl-2-O-methyl-α-L-arabinopyranosylazid (11) als auch das 3,4-O-Isopropyliden-2-O-methyl-α-L-ribopyranosylazid (27) gewonnen werden.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319830213
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