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  • 1
    Electronic Resource
    Electronic Resource
    Zur Synthese von Sialylglykosiden (Darstellung von Methyl-6-O-benzyl-(4,7,8,9-tetra-O-acetyl-5-acetylamino-3,5-didesoxy-D-glycero-α bzw. β-D-galacto-2-nonulopyranosäure-methylester)-α bzw. β-D-glucopyranosid) (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 1247-1251 
    Details
    ISSN: 1434-4475
    Keywords: 6-O-(N-Acetyl-D-neuraminyl)-D-glucopyranosides, derivatives ; Koenigs-Knorr reaction with silver triflate ; Sialylglucosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Silver triflate promoted condensations of 5-acetamido-4,7,8,9-tetra-O-acetyl-2-chloro-2,3,5-trideoxy-β-D-glycero-D-galacto-2-nonulopyranosidonic acid methylester with methyl-2,3,4-tri-O-benzyl-α or β-D-glucopyranoside to the title products are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00799939
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  • 2
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen an N-Acetylneuraminsäuren, 8 Synthese von 7-, 8-, 9-Desoxy- und 4,7-Didesoxyneuraminsäure (1988)
    Springer
    Monatshefte für Chemie 119 (1988), S. 127-141 
    Details
    ISSN: 1434-4475
    Keywords: Deoxygenation of sialic acids ; Xanthogenates of sialic acids ; Reaction of side chain deoxy-iodo sialic acids with tributyltinhydride ; Reaction of xanthogenates of sialic acids derivatives with tributyltinhydride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The 7- and 8-Iodnonulosonic acid derivatives1 and2 react with tributyltinhydride-AIBN to the 7- and 8-deoxy-N-acetylneuraminic acid derivatives3 a and4 a which after hydrolysis give the 7-deoxy-N-acetylneuraminic acid3 b (5-N-acetamido-3,5,7-trideoxy-β-D-galacto-2-nonulopyranosidonic acid=7-Deoxy-Neu5Ac) and 8-deoxy-N-acetylneuraminic acid4 b (5-N-acetamido-3,5,8-trideoxy-β-D-galacto-2-nonulopyranosidonic acid=8-Deoxy-Neu5Ac). The 4,8,9-tris-(t-butyldimethylsilyl)-N-acetylneuraminic acid derivative5 a yields after transformation to the 7-O-acetyl compound5 b and partial removing of the protecting groups the derivative5 c. Further reaction with theMitsunobu-reagent and methyliodide affords the 9-Iodocompound6 a which turned to the 8-O-acetylderivative6 b. Subsequent reduction by means of tributyltinhydride yields first the 9-deoxyderivative7 a and after hydrolysis the 9-deoxy-N-acetylneuraminic acid7 b (5-N-acetyl amido-3,5,9-trideoxy-D-glycero-β-d-galacto-2-nonulopy-ranosidonic acid=9-Deoxy-Neu5Ac). Another synthesis of7 b follows the route8 f →8 g →7 c. The Deoxy-N-acetylneuraminic acid3 b could be prepared also by an alternative procedure using the methyl-β-8,9-methylethylen-4-O-t-butyldimethylsilyl-N-acetylneuraminic acid methylester8 a via the intermediate compounds8 d and8 e. Application of the 8,9-O-methylethyliden-N-acetylneuraminic acid derivative8 opens an approach to the xanthogenates8 a and8 b which could be reduced to the deoxy-N-acetylneuraminic acid derivatives9 a and10 a. Hydrolysis of10 a yields the 4,7-dideoxy-N-acetylneuraminic acid10 b (5-N-acetamido-3,4,5,7-tetradeoxy-β-D-lyxo-2-nonulopyranosidonic acid=4,7-Dideoxy-Neu5Ac).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810094
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  • 3
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen an partiell silylierten Kohlenhydraten mittels Triphenylphosphan/Azodicarbonsäurediethylester, 4. Mitt.: Transformationen an Mannose und Galaktose (1980)
    Springer
    Monatshefte für Chemie 111 (1980), S. 289-307 
    Details
    ISSN: 1434-4475
    Keywords: Epoxisugars, preparation with triphenylphosphane/diethylazodicarboxylate ; Silylation, partially, of carbohydrates ; Substitution by means of triphenylphosphane/diethylazodicarboxylate/HN 3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of methyl β-D-galactopyranoside (1) with two equivalents oft-butyldimethylchlorosilane yields methyl 2,6-bis-O-(tBDMSi)-β-D-galactopyranoside (1 b), methyl 3,6-bis-O-(tBDMSi)-β-D-galactopyranoside (1 c) and methyl 4,6-bis-O-(tBDMSi)-β-D-galactopyranoside (1 d). Likewise methyl α-D-mannopyranoside (6) affords methyl 2,6-bis-O-(tBDMSi)-α-D-mannopyranoside (6 d) and methyl 3,6-bis-O-(tBDMSi)-α-D-mannopyranoside (6 b), which can be isomerised withTPP/DEAD to methyl 4,6-bis-O-(tBDMSi)-α-D-mannopyranoside (6 f). Methyl 6-O-(tBDMSi)-β-D-galactopyranoside (1 a) and methyl 6-O-(tBDMSi)-α-D-mannopyranoside (6 a) can be prepared from1 or6 with one equivalent oft-butyldimethylchlorosilane. Without an external nucleophile the sugar derivatives1 a and1 b react withTPP/DEAD to form the 3,4-carbonato-β-D-galactopyranosides1 h and1 i and the 3,4-carbonato-2-O-ethoxycarbonyl-β-D-galactoside (1 j). In contrast to the formation of the compound1 i by means ofTPP/DEAD the reaction of1 a withTPP and Di-t-butyl-azodicarboxylate (DTBAD) yields the 2,3-anhydro-β-D-taloside (4 b) and only a small amount of1 i. The epoxide4 b can be cleaved withp-nitrobenzoylchloride/pyridine to the 3-chloro-3-deoxy-2,6-di-O-p-nitrobenzoyl-β-D-idoside (5). Reaction of1 c and1 d withTPP/DEAD yields the 2,3-anhydro-β-D-gulopyranoside (2), which can be transformed with NaN3/NH4Cl to the 2-azido-2-deoxy-β-D-idopyranoside (3). Likewise6 a and6 d can be converted to the 3,4-anhydro-α-D-talosides (7 a and7 b). Reaction of7 b or6 d withTPP/DEAD/NH3 leads to 3,4-anhydro-2-azido-2-deoxy-α-D-galactopyranoside (8) and 3-azido-3-deoxy-α-D-altropyranoside (10), resp. The epoxide7 b is opened with NaN3/NH4Cl to the 4-azido-4-deoxymannosides (11 a and11 c) and the 3-azido-3-deoxy-α-D-idopyranoside (12), while the epoxide8 affords the 2,4-di-azido-2,4-dideoxy-α-D-glucopyranoside (9). Structures were elucidated by1H-NMR-analysis of the corresponding acetates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00938735
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  • 4
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen anN-Acetylneuraminsäure, 3 (1985)
    Springer
    Monatshefte für Chemie 116 (1985), S. 87-98 
    Details
    ISSN: 1434-4475
    Keywords: Acetolysis of methyl-9-O-acetyl-5-acetylamino-7,8-anhydro-4-O-(tBDMSi)-3,5-dideoxy-β-D-(andL)-glycero-D-galacto-2-nonulosidonic acid methylester, methyl-9-O-acetyl-5-acetylamino-7,8-anhydro-4-O-(tBDMSi)-3,5-dideoxy-β-D-glycero-L-altro-2-nonulosidonic acid methylester ; Configurational changes of sialic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract From methyl-5-acetylamino-7,8-anhydro-4,9-O-bis-(t-butyldimethylsilyl)-3,5-dideoxy-β-D-glycero-D-galacto-2-nonulopyranosidonic acid methylester (1) the derivatives1 a and1 b were obtained by removing the 9-O-(t-butyldimethylsilyl)group withBu 4NF, followed by acetylation. Treatment of1 b with 80% acetic acid and acetanhydride/pyridine yields the 8-epi-N-acetylneuraminic acid derivative2 a and the 7-epi-N-acetylneuraminic acid derivative3 a in a ratio of 3:1 (Scheme 1). The structure elucidation of2 b was achieved by converting2 b via the 4,9-bis-O-(tBDMSi)-8-O-tosyl-derivative2 d into the epoxide1 (Scheme 2). Using the same sequence the epoxides4 and5 were transformed into theN-acetylneuraminic acid derivative6 a and the 7,8-bis-epi-N-acetylneuraminic acid derivative7 a (Scheme 3). After treatment with sodium hydroxide and 0.025m HCl and Dowex 50 H+ the 8-epi-, 7-epi- and 7,8-bis-epi-N-acetylneuraminic acids2,3, and7 were obtained. These three compounds were tested withCMP-N-acetylneuraminic acid synthetase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798282
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  • 5
    Electronic Resource
    Electronic Resource
    Röntgenstrukturanalyse des Methyl-5-acetylamino-7,8-anhydro-4,9-bis-O-(t-butyldimethylsilyl)-3,5-didesoxy-L-glycero-β-D-galakto-2-nonulopyranosidon-säuremethylesters (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 1105-1111 
    Details
    ISSN: 1434-4475
    Keywords: Crystal structure ; Oxiranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An X-ray crystal structure analysis of the title compound was carried out at −168°C in order to assign the stereochemistry around the oxirane: C25H49NO8Si2, trigonal, R3,a=25.18(1),c=13.55(1) Å (hexagonal axes),Z=9,d x =1.105. The structure was solved with direct methods and refined to anR-factor of 0.086.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905464
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  • 6
    Electronic Resource
    Electronic Resource
    Interaction ofN-acetyl-4-, 7-, 8- or 9-deoxyneuraminic acids andN-acetyl-4-, 7- or 8-mono-epi- and-7,8-di-epineuraminic acids withN-acetylneuraminate lyase (1987)
    Springer
    Glycoconjugate journal 4 (1987), S. 361-369 
    Details
    ISSN: 1573-4986
    Keywords: N-acetylneuraminate lyase ; N-acetyl-deoxyneuraminic acids ; N-acetyl-epineuraminic acids ; sialic acids ; competitive inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Various deoxy- and epi-derivatives ofN-acetylneuraminic acid were synthesized and tested for their substrate properties withN-acetylneuraminate lyase fromClostridium perfringens.N-Acetyl-9-deoxyneuraminic acid is a good substrate,N-acetylneuraminic acid derivatives with epimeric configuration at C-7, C-8 or both are cleaved slowly, whileN-acetyl-4-epi-,N-acetyl-4-deoxy-,N-acetyl-7-deoxy-andN-acetyl-8-deoxyneuraminic acid are resistant to enzyme action.N-Acetyl-4-deoxyneuraminic acid andN-acetyl-4-epineuraminic acid competitively inhibit the enzyme. These studies give further insight into a mechanism proposed for the reversible cleavage of sialic acids byN-acetylneuraminate lyase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01048369
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  • 7
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen an N-Acetylneuraminsäure, 2 (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 2055-2065 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transformations with N-Acetylneuraminic Acid, 2From methyl 5-acetylamino-3,5-dideoxy-β-D-glycero-D-galacto-2-nonulopyranosidonic acid methyl ester (1) the 8,9-O-isopropylidene derivative 2 was obtained, which was transformed with pyridinium chlorochromate (PCC) or pyridinium fluorochromate (PFC) into the 4-keto derivative 3 (Scheme 1). Treatment of 2 with triphenylphosphane/diethyl azodicarboxylate and hydrazoic acid yields the oxazoline derivative 4. Compound 4 can be converted with hydrochloric acid in methanol to give the methyl 4-O-acetyl-5-acetylamino-3,5-dideoxy-β-D-glycero-D-talo-2-nonulopyranosidonic acid methyl ester (5a) and the derivatives 5b - d. methyl 5-acetylamino-7,8-anhydro-4,9-bis-O-(tert-butyldimethylsilyl)-3,5-dideoxy-α-L-glycero-2-nonulopyranosidonic acid methyl ester (6) and the analogous 7,8-anhydro-β-D-glycero-L-altro derivative 8 were transformed with chlorotrimethylsilane and sodium iodide into the corresponding 8-iodo-8-deoxy-β-D-glycero-d-galacto- or the 8-iodo-8-deoxy-α-L-glycero-L-altro-2-nonulopyranosidonic acid methyl ester derivatives 7b-d or 9b, respectively (Scheme 2). Treatment of 10 with N,N-dimethylformamide dimethyl acetal yields - via the intermediates 11 and 12 - either with acetic anhydride the epoxides 6 and 8 or with methyl iodide the methyl 5-acetylamino-4,9-bis-O-(tert-butyldimethylsilyl)-3,5,8-trideoxy-7-O-formyl-8-iodo-α-L-glycero-D-galacto-2-nonulopyranosidonic acid methyl ester (13) and the 7-deoxy-7-iodo-β-D-glycero-L-altro derivatives 14 and 14a. Reaction of 13, 14, or 14a with sodium methoxide yields the 7,8-anhydro-β-D_glycero-D-galacto-2-Nonulopyranosidonic acid methyl ester derivative 15, the 9-O_(tert-butyldimethylsilyl) group can be selectively removed with tetrabutylammonium fluoride to give 15a (Scheme 3). Structure elucidation was achieved by 1H NMR spectra of the corresponding acetates.
    Notes: Methyl-5-acetylamino-3,5-didesoxy-β-D-glycero-D-galacto-2-nonulopyranosidonsäure-methylester (1) wurde über das 8,9-O-Isopropylidenderivat 2 mit Pyridiniumchlorochromat (PCC) oder Pyridiniumfluorochromat (PFC) in das 4-Ketoderivat 3 übergeführt (Schema 1). Mit Triphenyl-phosphan/Azodicarbonsäure-diethylester und Stickstoffwassersäure ergibt 2 das Oxazolinderivat 4, das mit Salzsäure in Methanol in den Methyl-4-O-acetyl-5-acetylamino-3,5-didesoxy-β-D-glycero-D-talo-2-nonulopyranosidonsäure-methylester (5a) und die Derivate 5b-d umgewandelt wird. Der Methyl-5-acetylamino-7,8-anhydro-4,9-bis-O-(tert-butyldimethylsilyl)-3,5-didesoxy-α-L-glycero-D-galacto-2-nonulopyranosidonsäure-methylester (6) und das analoge 7,8-Anhydro-β-D-glycero-L-altro-Derivat 8 wurden mit Chlortrimethylsilan und Natriumiodid zu den entsprechenden 8-Iod-8-desoxy-β-D-glycero-D-galacto- bzw. 8-Iod-8-desoxy-α-L-glycero-L-altro-2-nonulopyranosidonsäure-methylester-Derivaten 7b-d bzw. 9b geöffnet (Schema 2). 10 liefert mit N,N-Dimethylformamid-dimethylacetal über die Zwischenstufen 11 und 12 mit Acetanhydrid die Epoxide 6 und 8 oder mit Methyliodid den Methyl-5-acetylamino-4,9-bis-O-(tert-butyldimethylsilyl)-3,5,8-tridesoxy-7-O-form yl-8-iod-α-L-glycero-D-galacto-2-nonulopyranosidonsäure-methylester (13) und die 7-Desoxy-7-iod-β-D-glycero-L-altro-Derivate 14 und 14a. 13, 14 und 14a können mit Natriummethanolat in das 7,8-Anhydro-β-D-glycero-D-galacto-2-nonulopyranosidonsäure-methylester-Derivat 15 übergeführt werden, dessen 9-O-(tert-Butyldimethylsilyl)-Gruppe selektiv mit Tetrabutylammoniumfluorid unter Bildung von 15a entfernt werden kann (Schema 3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319831202
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  • 8
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen an partiell silylierten Kohlenhydraten, 61) Transformationen an N-Acetylneuraminsäure (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1-13 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structural Modifications of Partially Silylated Carbohydrates by Means of Triphenylphosphane and Azodicarboxylate, 61). - Transformations with N-Acetylneuraminic AcidFrom methyl 5-acetylamino-3,5-dideoxy-D-glycero-β-D-galacto-2-nonulopyranosidonic acid methyl esters 1 the 9-O-, 4,9-bis-O-, or 4,8,9-tris-O-(tert-butyldimethylsilyl)nonulopyranosidonic acid methyl ester derivatives 1a,1b,and were obtained 1e (Scheme 1). Treatment of 1c with acetanhydride/pyridine yields 1d which is converted into 1i with migration of one acyl group by means of tetrabutylammonium fluoride. Transformation of 1i with triphenylphosphane/diethylazodicarboxylate/hydrazoic acid (TPP/DEAD/HN,) yields a mixture of 9-azido-9-deoxy-o-glycero-p-D-galacto- and 8-azido-8-deoxy-1.-glycero-β-D-galacto-2-nonulopyranosidonic acid methyl ester derivatives 2 and 3 (Scheme 2). 1c can be transformed with triphenylphosphane(TPP) and diethyl azodicarboxylate (DEAD) to the 7,8-anhydrononulopyranosidonic acid methylester derivatives 4 and 5. Compound 5 can be converted with NaN,/NH,CI to the 5-acetylamino-8-azido-8-deoxyneuraminic acid derivative 6a (Scheme 3). Reaction of 1e with TPP/DEAD/HN, affords under 1.3-neighbouring group participation methyl 4,8,9-tris-O-(tert-butyldimethylsilyl)-3,5-d∼deoxy-5-(5-methyl-l-tetrazolyl)-D-glycero-β-D-altro-2-nonulopyranosidonic acid methyl ester (7a) (Scheme 4).
    Notes: Aus den Methyl-5-acetylamino-3,5-didesoxy-D-glycero-β-D-galakto-nonulopyranosidonsäure-methylestern 1 wurden die 9-O-, 4,9-Bis-O- und 4,8,9-Tris-O-(tert-butyldimethylsilyl)etherderivate 1a, 1c und 1e hergestellt (Schema 1). Das aus 1c gewonnene 7,8-Diacetylderivat 1d geht mit Tetrabutylammoniumfluorid unter Verlust einer Silylgruppe und Acetylwanderung in 1i über. Letzteres liefert mit Triphenylphosphan/Azodicarbonsäure-diethylester/Stickstoffwasserstoffsäure (TPP/DEAD/HN3) ein Gemisch aus den 9-Azido-9-desoxy-D-glycero-β-D-galakto- und 8-Azido-8-desoxy-L-glycero-β-D-galakto-2-nonulosonsäurederivaten 2 und 3 (Schema 2). Aus 1c erhält man mit Triphenylphosphan/Azodicarbonsäure-diethylester (TPP/DEAD) die 7,8-Anhydrononulosonsäurederivate 4 und 5; letzteres wurde mit NaN3 und NH4Cl in das 5-Acetylamino-8-azido-8-desoxyneuraminsäurederivat 6a übergeführt (Schema 3). Setzt man 1e mit TPP/DEAD/HN3 um, so erhält man als Folge einer 1,3-Nachbargruppenreaktion der 5-Acetylaminogruppe den Methyl-4,8,9-tris-O-(/er/-butyldimethylsilyl)-3,5-didesoxy-5-(5-methyl-1-tetrazolyl)-D-glycero-β-L-altro-2-nonulopyranosidonsäure-methylester (7a) (Schema 4).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820102
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  • 9
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    Electronic Resource
    Zur Aktivierung partiell silylierter Kohlenhydrate mittels Triphenylphosphan/AzodicarbonsäureesterGilt als 2. Mitt. in der Reihe: Reaktionen an Kohlenhydraten mit Hilfe von Triphenylphosphan/Azodicarbonsäureester;. 1. Mitt. vgl. [1]. (1978)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 61 (1978), S. 1832-1841 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Activation of Partially Silylated Carbohydrates Using Triphenylphosphane/DiethylazodicarboxylateReaction of methyl α-D-glucopyranoside (1) with two equivalents of t-butyldimethylchlorosilane yields methyl 2,6-bis[O-(t-butyldimethylsilyl)]-α-D-glucopyranoside (1a) and methyl 3,6-bis[O(t-butyldimethylsilyl)]-α-D-glucopyranoside (1b) in a ratio of 4:1. The anomeric β-pyranoside 2 affords methyl 2,6-bis[O(t-butyldimethylsilyl)]-β-D-glucopyranoside (2a) and methyl 3,6-bis[O(t-butyldimethylsilyl)]-β-D-glucopyranoside (2b) in nearly equal amounts. 2b is isomerized to methyl 4,6-bis[O(t-butyldimethylsilyl)]-β;-D-glucopyranoside (2c) (83%) and 2a (10%) with triphenylphosphane/diethylazodicarboxylate. Structures were assigned by NMR.-analysis and CD.-analysis of the corresponding benzoates 1c, 1d and 2d and of the acetates 2e and 2f.1a is transformed into methyl 4-azido-2, 6-bis[O(t-butyldimethylsilyl)]-4-deoxy-α-D-galactopyranoside (3) with triphenylphosphane/diethylazodicarboxylate/HN3. 2a and 2c yield the 3-azido-allosides 5 and 7 respectively under similar conditions. The activation by triphenylphosphane/diethylazodicarboxylate is high enough to introduce also p-nitrobenzoate groups with inversion of configuration at the reaction center. By this way 1a and 2a give methyl 2, 6-bis[O(t-butyldimethylsilyl)]-4-O-p-nitrobenzoyl-α-D-galactopyranoside (4) and methyl 2, 6-bis[O-(t-butyldimethylsilyl)]-3-O-ptrobenzoyl-β-D-allopyranoside (6) respectively. For elucidation of structures the acetate derivatives 3a-7a were prepared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19780610528
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  • 10
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    Electronic Resource
    Strukturelle Abwandlungen an partiell silylierten Kohlenhydraten mittels Triphenylphosphin/Azodicarbonsäure-diäthylester. 3. Mitteilung [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 327-343 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structural Modification on Partially Silylated Carbohydrates by Means of Triphenylphosphine/Diethyl AzodicarboxylateReaction of methyl 2, 6-bis-O-(t-butyldimethylsilyl)-β-D-glucopyranoside (1a) with triphenylphosphine (TPP)/diethyl azodicarboxylate (DEAD) and Ph3P · HBr or methyl iodide yields methyl 3-bromo-2, 6-bis-O-(t-butyldimethylsilyl)-3-deoxy-β-D-allopyranoside (3a) and the corresponding 3-deoxy-3-iodo-alloside 3c (Scheme 1). By a similar way methyl 2, 6-bis-O-(t-butyldimethylsilyl)-α-D-glucopyranoside (2a) can be converted to the 4-bromo-4-deoxy-galactoside 4a and the 4-deoxy-4-iodo-galactoside 4b. In the absence of an external nucleophile the sugar derivatives 1a and 2a react with TPP/DEAD to form the 3,4-anhydro-α- or -β-D-galactosides 5 and 6a, respectively, while methyl 4, 6-bis-O-(t-butyldimethylsilyl)-β-D-glucopyranoside (1b) yields methyl 2,3-anhydro-4, 6-bis-O-(t-butyldimethylsilyl)-β-D-allopyranoside (7a, s. Scheme 2). Even the monosilylated sugar methyl 6-O-(t-butyldimethylsilyl)-α-D-glucopyranoside (2b) can be transformed to methyl 2,3-anhydro-6-O-(t-butyldimethylsilyl)-β-D-allopyranoside (8; 56%) and 3,4-anhydro-α-D-alloside 9 (23%, s. Scheme 3). Reaction of 1c with TPP/DEAD/HN3 leads to methyl 3-azido-6-O-(t-butyldimethylsilyl)-3-deoxy-β-D-allopyranoside (10). The epoxides 7 and 8 were converted with NaN3/NH4Cl to the 2-azido-2-deoxy-altrosides 11 and 13, respectively, and the 3-azido-3-deoxy-glucosides 12 and 14, respectively (Scheme 4 and 5). Reaction of 7 and 8 with TPP/DEAD/HN3 or p-nitrobenzoic acid afforded methyl 2,3-anhydro-4-azido-6-O-(t-butyldimethylsilyl)-4-deoxy-α- and -β-D-gulopyranoside (15 and 17), respectively, or methyl 2,3-anhydro-6-O-(t-butyldimethylsilyl)-4-O-(p-nitrobenzoyl)-α- and -β-D-gulopyranoside (16 and 18), respectively, without any opening of the oxirane ring (s. Scheme 6). - The 2-acetamido-2-deoxy-glucosides 19a and 20a react with TPP/DEAD alone to form the corresponding methyl 2-acetamido-3,4-anhydro-6-O-(t-butyldimethylsilyl)-2-deoxy-galactopyranosides (21 and 22) in a yield of 80 and 85%, respectively (Scheme 7). With TPP/DEAD/HN3 20a is transformed to methyl 2-acetamido-3-azido-6-O-(t-butyldimethylsilyl)-2,3-didesoxy-β-D-allopyranoside (25, Scheme 8). By this way methyl 2-acetamido-3,6-bis-O-(t-butyldimethylsilyl)-α-D-glucopyranoside (19b) yields methyl 2-acetamido-4-azido-3,6-bis-O-(t-butyldimethylsilyl)-2,4-dideoxy-α-D-galactopyranoside (23; 16%) and the isomerized product methyl 2-acetamido-4,6-bis-O-(t-butyldimethylsilyl)-2-deoxy-α-D-glucopyranoside (19d; 45%). Under the same conditions the disilylated methyl 2-acetamido-2-deoxy-glucoside 20b leads to methyl 2-acetamido-4-azido-3,6-bis-O-(t-butyldimethylsilyl)-2,4-dideoxy-β-D-galactopyranoside (24). - All Structures were assigned by 1H-NMR. analysis of the corresponding acetates.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630203
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