Desulfation of Sulfated Carbohydrates Mediated by Silylating Reagents

Selective sulfation of carrageenans and the influence of sulfate regiochemistry on anticoagulant properties

“…While several approaches have been reported for the desulfation of carbohydrates (Kolender & Matulewicz, 2004;Miller & Blunt, 1998;Takano, Kanda, Hayashi, Yoshida, & Hara, 1995), in this work, we selected the Nagasawa, Inoue, and Kamata (1977) method. Sample 6 showed a decrease in DS (1.1-0.1) together with a reduction in the molecular weight (Table 3).…”

Desulfation of sulfated galactans with chlorotrimethylsilane. Characterization of β-carrageenan by 1H NMR spectroscopy

“…9 In addition, a selective desulfation method for primary alcohols using the silylating reagents N,O-bis(trimethylsilyl)acetamide (BTSA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BTSTFA), was reported in 1992 by Takano et al 10 A comparison between desulfation rate constants for methyl a-D Dgalactoside 3-sulfate and methyl a-D D -galactoside 6-sulfate, relative to the solvolytic reaction in pyridine, led to the classification of various silylating reagents in three groups: (a) inefficient for desulfation, (b) selective towards desulfation of the 6-position and (c) nonselective but still active desulfating agents. 11 Even though the efficiency of the compounds included in group (c) was lower than that one exhibited by the selective agents, they could be considered as potentially useful for desulfation of primary and secondary hydroxyl groups. Among these reagents, chlorotrimethylsilane (CTMS) was one of the most promising compounds.…”

Molecular Characteristics and Gelling Properties of the Carrageenan Family, 1. Preparation of Novel Carrageenans and their Dilute Solution Properties

“…[4 -6] Although band h-carrageenans are less available in nature, they can be prepared by desulfonation from j and k-carrageenan, [7][8][9] respectively. However, its gelation behavior differs characteristically depending on the type of carrageenans.…”