• Title/Summary/Keyword: L-gulose

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The Acid Sensitivity of Gulose and Mannose in Chemically-Reduced Alginates Obtained from Pseudomonas syringae

  • Ashby, Richard D.;Day, Donal F.;Kim, Du-Woon
    • Food Science and Biotechnology
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    • v.15 no.4
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    • pp.555-558
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    • 2006
  • The chemical reduction of Pseudomonas syringae subsp. phaseolicola alginates produces neutral polymers of D-mannose and L-gulose in source specific ratios. L-Gulose was highly sensitive to degradation by 1N HCl at $100^{\circ}C$. As hydrolysis time increased, gulose recovery decreased to 22% after 4 hr, whereas 98% of the D-mannose was recovered under the same conditions. Thin layer chromatography showed the formation of a second product upon L-gulose acid hydrolysis. This new product had a rate of flow (Rf) value of 0.58, identical to that of 1,6 anhydro-${\beta}$-D-mannopyranose and very close to that of 1,6 anhydro-${\beta}$-D-glucopyranose (Rf=0.60). Because of the difference in acid sensitivity between L-gulose and D-mannose, normal acid hydrolytic techniques applied to reduced alginates produces erroneous mannuronic acid (M): guluronic acid (G) ratio's unless one accounts for the differential rates of destruction of each sugar.

Synthesis of L-1,3-Dioxolane and L-1,3-Oxathiolane Pyrimidine Nucleosides (L-1,3-Dioxolane 및 L-1,3-Oxathiolane 피리미딘 뉴크레오사이드의 합성)

  • Hong, Joon-Hee;Park, Jeong-Ha;Song, Ji-Yeon;Choi, Bo-Gil;Chung, Byung-Ho;Kim, Joong-Hyup;Lee, Chong-Kyo;Chung, Won-Keun;Chun, Moon-Woo
    • YAKHAK HOEJI
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    • v.38 no.6
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    • pp.775-781
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    • 1994
  • $({\pm})-Dioxolane-T$ and$({\pm})-BCH-189$ are know to possess anti-HIV activities, and less to xicities compared to other dideoxynucleoside AIDS drugs. We have synthesized 34 different enantiomerically pure nucleosides by glycosylation of L-1,3-dioxolanyl acetate and L-1,3-oxathiolanyl acetate sugar moieties with uracil or 6-azauracil with alkyl chains$(C_1-C_3)$ on 5 or 6 position.

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