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  • 1
    Electronic Resource
    Electronic Resource
    A General Method for the Synthesis of C-Glycosides of Nojirimycin (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1315-1321 
    Details
    ISSN: 0947-3440
    Keywords: C-Glycosides ; Azasugars ; Piperidinosyl fluoride ; O-Piperidinosyl trichloroacetimidate ; Nojirimycin ; Deoxynojirimycin ; Glycosylations ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl 2,3,4,6-tetra-O-acetyl-N-(benzyloxycarbonyl)nojirimycin (3) can be readily transformed into the corresponding azaglycal 6 or fluoride 7, which are versatile glycosyl/piperidinosyl donors. Reaction of 7 with allyltrimethylsilane, propinyltrimethylsilane, trimethylsilyl cyanide, and trimethylsilyl enol ether as carbon nucleophiles, afforded, in the presence of BF3 · OEt2 as catalyst, the corresponding C-glycosides 8-10 and 12-14 in good yields. The anomeric configurations of the C-glycosides are ascertained with the help of ROESY-NMR data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970706
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of carbon-bridged N-acetyl-c-lactosamine and derivatives (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 2113-2121 
    Details
    ISSN: 0947-3440
    Keywords: C-Saccharides ; C-Glycosides ; C-Lactosamine ; 1-Lithiogalactal ; Vinyllithium ; Branched sugars ; Glucosamine, C-formyl ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-C-Formyl-2-azidoglucopyranoside 12a, required for N-acetyl-C-lactosamine synthesis as electrophile, was obtained from thexyldimethylsilyl 2-azido-2-deoxy-glucopyranoside 3 via readily available 4-O-unprotected 6a and then 4-C-methylene derivative 8a in overall seven steps. Alternatively, regioselective silylation of 3 with tert-butyldimethylsilyl chloride gave 4-O-unprotected 6b which was transformed by a similar reaction sequence into 12a. In order to circumvent a Wittig reaction, 6a was transformed into triflate 13 the reaction of which with 4-C-cyano derivative 14 followed by reduction with DIBAH and base-catalyzed isomerization also afforded 12a. Reaction of 12a with 1-C-lithiated 2-phenylsul-finyl-D-galactal 15 as nucleophile furnished C-disaccharide intermediates 16a and 16b as diastereoisomers. Ensuing removal of the phenylsulfinyl group with Raney nickel and diastereospecific 2b-hydrogen and 3b-hydroxy transfer afforded β(1→4)-connected N-acetyl-C-lactosamines 19a and 19b; their structures were deduced from derivatives 20a, b and 21a, b on the basis of 1H-NMR data. Hydrogenolytic O-debenzylation of 19b afforded hydroxymethylene-bridged N-acetyl-C-lactosamine 2b′.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199512297
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  • 3
    Electronic Resource
    Electronic Resource
    Glycal-1-ylmethylphosphonates - precursors of glycosyltransferase inhibitors (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 297-303 
    Details
    ISSN: 0170-2041
    Keywords: Carbohydrates ; Glycals ; C-Glycosides ; Hept-2-enoses, lyxo- ; D-Galactal-1-ylmethylphosphonates ; L-Fucal-1-ylmethylphosphonates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct lithiation of 2-phenylsulfinyl- and 2-phenylsulfonylsubstituted galactal derivatives 3a-c and subsequent reaction with DMF gave 1-C-formyl derivatives 4a-c. Reduction afforded hydroxymethyl derivatives 5a-c which were transformed into mesylates 7 and 9, respectively. Treatment with trimethyl phosphite furnished phosphonates 8 and 10; by treatment with sodium in liquid ammonia and subsequent reaction with acetic anhydride in pyridine both compounds were converted into monomethyl galactal-1-ylmethylphosphonate (11) which could not be completely demethylated without structural change. O-Acetyl-protected mesylate 18, obtained from galactosyl cyanide in a few steps, was transformed into bromide 19 which on treatment with P(OSiMe3)3 gave bis(trimethylsilyl) phosphonate 20. Reaction with NaOMe/MeOH afforded the unprotected disodium salt of D-galactal-1-ylmethylphosphonate 1. Similarly, from L-fucopyranosyl cyanide 22 the corresponding target molecule 2 was obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940312
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of Carbon-Bridged C-Lactose and Derivatives (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 975-981 
    Details
    ISSN: 0170-2041
    Keywords: C-Saccharides ; C-Glycosides ; 1-Lithiogalactal ; Vinyllithium ; Glucose, C-formyl- ; Carbohydrates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-C-Formylglucopyranoside 9 was readily obtained from 4-O-unprotected glucose derivative 4 in four steps, each step giving a high product yield. Reaction with 1-C-lithiated 2-phenylsulfinyl-D-galactal 10 as nucleophile furnished C-disaccharide intermediates 11a and 11b as diastereoisomers. Ensuing removal of the phenylsulfinyl group with Raney nickel and regio- and diastereospecific 2b-hydrogen and 3b-hydroxy transfer afforded β(1-4)-connected C-lactosides 13a and 13b, respectively; their structures were deduced from derivatives 14a, b and 16a, b on the basis of 1H-NMR data. Hydrogenolytic O-debenzylation of 13a and 13b afforded hydroxymethylene-bridged C-lactose 2a and 2b, respectively. Regioselective O-benzylation of 13a gave preferentially 1b-O-unprotected derivative 17aa which furnished upon oxidation carbonyl-bridged C-lactose derivative 19. Deoxygenation at C-1b of 17aa and subsequent hydrogenolytic O-debenzylation furnished methylene-bridged C-lactose 1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419941004
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