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    Regio- and stereospecific synthesis of rac-carbasugar-based cyclohexane pentols; Investigations of their α- and β-glucosidase inhibitions
    (Pergamon-Elsevier Science Ltd, 2018) Karakilic, Emel; Durmus, Sumeyye; Sevmezler, Sedat; Sahin, Onur; Baran, Arif
    In the present study, (3aR,7aS)-1,3,3a,4,7,7a-hexahydroisobenzofuran was submitted to photooxygenation and two isomeric hydroperoxides were successfully obtained. Without any further purification, reduction of the hydroperoxides with titanium tetraisopropoxide catalyzed by dimethyl sulfide gave two alcohol isomers in high yields. After acetylation of alcohol with Ac2O in pyridine, epoxidation reaction of formed monoacetates with mCPBA, then chromatographed and followed by hydrolysis of the acetate groups with NH3 in CH3OH resulted in the formation of epoxy alcohol isomers respectively. These epoxy alcohol isomers were subjected to trans-dihydroxylation reaction with acid (H2SO4) in the presence of water to afford triols. Acetylation of the free hydroxyl groups produced benzofuran triacetates in high yields. Ring-opening reaction of furan triacetates with sulfamic acid catalyzed in the presence of acetic acid/acetic anhydrate and subsequently hydrolysis of the acetate groups with ammonia gave the targeted cyclohexane carbasugar-based pentols. All products were separated and purified by chromatographic and crystallographic methods. Structural analyses of all compounds were conducted by spectral techniques including NMR and X-ray analyses. The biological inhibition activity of the target compounds was tested against glycosidase enzymes, alpha- and beta-glucosidase.
  • [ X ]
    Öğe
    Synthesis of bicyclo[2.2.2]octane-2,3,5,6,7,8 hexols (Bishomoinositols) as glycosidase inhibitors
    (Amer Chemical Soc, 2008) Baran, Arif; Guenel, Aslihan; Balci, Metin
    For the construction of the bicyclo[2.2.2] octane skeleton, 2,2-dimethyl-3a,7a-dihydro-1,3-benzodioxole was reacted with vinylene carbonate to give two isomeric cycloadditon products having the bicyclo[2.2.2]octane skeleton. Hydrolysis of the ketal ring and the opening of the carbonate functionality, followed by hydroxylation of the remaining double bond resulted in the formation of a symmetrical hexol. Epoxidation of the double bond in the cycloaddition products and the subsequent ring-opening reactions produce two additional hexol derivatives. One of the synthesized molecules exhibited enzyme-specific inhibition against alpha-glycosidase.