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  • cleavage reactions  (1)
  • kinetics  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of the 2-Deoxyisomaltose Analogue of Acarbose by an Improved Route to Chiral Valieneamines (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 453-462 
    Details
    ISSN: 0947-6539
    Keywords: cleavage reactions ; enzyme inhibitors ; glycosides ; rearrangements ; transition states ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A 2-deoxyisomaltose analogue of acarbose was stereoselectively synthesised in 11 steps with a total yield of 7% starting from 2,6-dibromo-2, 6-dideoxy-D-mannono-1,4-lactone (6). The latter was reduced to the lactol, converted to the methyl glycoside (7) and hydrogenated to the methyl 6-bromo-2,6-dideoxyglycoside (8). Benzylation of the hydroxy groups, elimination of bromine to a 5-ene and Ferrier carbocyclisation gave (2S, 3R)-2,3-bisbenzyloxycyclohex-5-enone (12). 1, 2-addition of benzyloxymethyl lithium at -110°C gave a 6:1 mixture of tertiary alcohols 13; the (1S) isomer was the major one. Reaction with trichloroacetyl isocyanate gave a carbamate 19, which, when dehydrated to the cyanate, spontaneously underwent [1,3] sigmatropic rearrangement to an isocyanate, which on addition of methanol gave the methylcarbamate 20. Basic hydrolysis of this compound gave (2R, 3R,5R)-5-amino-1-benzyloxymethyl-2,3
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030318
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  • 2
    Electronic Resource
    Electronic Resource
    1-Azafagomine: A Hydroxyhexahydropyridazine That Potently Inhibits Enzymatic Glycoside Cleavage (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 940-947 
    Details
    ISSN: 0947-6539
    Keywords: chemoselectivity ; enzyme inhibitors ; glycosidases ; kinetics ; pyridazines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (3,4-trans-4,5-trans)-4,5-dihydroxy-3-hydroxymethylhexahydropyrida-zine (16) was synthesized in four steps from 2,4-pentadienol (22) and 4-phenyl-triazolin-3,5-dione (18) in an overall yield of 32%. In the first step a Diels-Alder reaction between 18 and 22 gave (π)-2-hydroxymethyl-8-phenyl-1,6,8-triazabicyclo[4.3.0]non-3-ene-7,9-dione (23c) in 88% yield. Epoxidation of 23c with trifluoromethyl(methyl)dioxirane, generated in situ, gave the trans epoxide 24c in 62% yield. Hydrolysis of the epoxide with perchloric acid gave stereoselectively (2,3-trans-3,4-trans)-3,4-dihydroxy-2-hydroxy-methyl-8-phenyl-1,6,8-triazabicyclo[4.3.0]-nonane-7,9-dione (26) in 73% yield. In the fourth and final step, hydrazinolysis of 26 gave 16 in 84% yield. Pyridazine 16 was found to be a potent inhibitor of α-and β-glucosidase, isomaltase and glyco-gen phosphorylase, while galactosidases and α-mannosidase were not inhibited. The inhibition of β-glucosidase is independent of pH, and was found to be due to unprotonated 16.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030616
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