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  • Synthesis, structural studies, and cytostatic evaluation of 5,6-di-O-modified L-ascorbic acid derivatives
    Gazivoda, Tatjana ...
    The 5,6-di-O-tosylated derivative of l-ascorbic acid was synthesized by selective protection and deprotection of 2,3- and 5,6-dihydroxy functional groups involving 5,6-ditosylation in the final step, ... while the novel 6-acetoxy, 6-hydroxy, and 6-chloro derivatives of 4,5-didehydro-l-ascorbic acid were obtained by reaction of ditosylated compound with nucleophilic reagents. The analysis of 3JH-4-H-5 homonuclear coupling constants shows that all l-ascorbic acid derivatives except for epoxy and 4,5-didehydro compounds exist in high population as gauche conformers across C-4-C-5 bonds, while 3JC-3-H-5 heteronuclear coupling constants in 4,5-didehydro derivatives indicate cis geometry along C-4-C-5 double bond. The X-ray crystal structure analysis of 2,3-di-O-benzyl-5,6-epoxy- and 5,6-isopropylidene-l-ascorbic acid shows that the oxygen atoms attached at positions 2 and 3 of the lactone ring are disposed in a synperiplanar fashion. Besides that, the dioxolane ring adopts half-chair conformation. The molecules of epoxy derivative are joined into infinite chains by one weak hydrogen bond of C-HO type. Two O-HO, and C-HO hydrogen bonds link the molecules of 5,6-di-O-isopropylidene compound into two-dimensional network. 6-Chloro derivative of 2,3-di-O-benzyl-l-ascorbic acid showed the best cytostatic effects against alltested malignant tumor cells (IC50Č 18 M).
    Vir: Carbohydrate research. - ISSN 0008-6215 (Vol. 341, no. 4, 2006, str. 433-442)
    Vrsta gradiva - članek, sestavni del
    Leto - 2006
    Jezik - angleški
    COBISS.SI-ID - 3438874

vir: Carbohydrate research. - ISSN 0008-6215 (Vol. 341, no. 4, 2006, str. 433-442)
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