Sugars sulfonates

The displacement is effected preferentially by a nucleophilic group already in the molecule. Thus, in the above reaction there is no evidence that OTs- is displaced by the external ion, OMe-, under the conditions used, nor is there ahy displacement of OTs- of a sugar sulfonate by OAc-, Buch as was found to occur when the sulfonate of a monohydric aliphatic alcohol was treated with potassium acetate.11... 

Bimolecular, nucleophilic-displacement reactions of sugar sulfonates have been reviewed in this Series.58,59 The value of these reactions in the preparation of deoxyhalo sugars has been emphasized by Hanessian.92... 

The sugar sulfonic acid is l-0-(6-deoxy-6-sulfo-a-D-glucopyranosyl)-glycerol isolated from a plant sulfolipid.46 The plant sulfolipid... 

The importance of sugar sulfonates as synthetic intermediates has been widely recognized.77,78 Selective methanesulfonylation and p-toluenesulfonylation of maltose and its derivatives has been studied. Umezawa and coworkers used sequential p-toluenesulfonylation and acetylation to obtain crystalline l,2,3,2, 3, 4 -hexa-0-acetyl-6,6 -di-0-p-tolylsulfonyl-/3-maltose in 45% yield.79 Dimolar methanesulfonylation of methyl /3-maltoside followed by acetylation afforded crystalline methyl 2,3,2, 3, 4 -penta-0-acetyl-6,6 -di-0-(methylsulfonyl)-/3-maltoside. The mother liquor also yielded a small proportion of a... 

The foregoing method of preparation of sugar thiocyanates109,110 by Sn2 displacement of a sulfonyloxy group has been reported by many workers.111 143 Displacement of sugar sulfonate groups by various nucleo-... 

In addition to the aldonic acid formation a minor fraction of the monosaccharides is converted to sugar sulfonic acids. 

Application of mass spectrometry to carbohydrate derivatives has been reviewed in this Series. Although no example of its application to sugar sulfonates was cited, such experiments have undoubtedly been performed samples having very low volatility may be examined after direct introduction into the ion-source chamber. Sulfonates of 6-chloro-6-deoxy sugars were first identified in this way, and interpretation of the mass spectra was aided by the presence of fragments containing C1 and C1. 

Many examples were earlier reported of acid hydrolysis of acetals and glycosides of sugar sulfonates in which no loss of a sulfonate group occurred in addition, by suitable choice of acidic conditions, deacetalation may be performed without concurrent hydrolysis of a... 

The differences in reactivity of acetals of sugar sulfonates demonstrate the need for care in the choice of acetal protecting groups in preparative work. 

Reduction of sugar sulfonates by lithium aluminum hydride, 269 Refractive index, mutarotation measurement by, 50 R-Enzyme, 363 Rhamnose... 

Silver methanesulfonate, sulfonylation of carbohydrates by, 239 Sodium methoxide, reaction with sugar sulfonates, 279 Solubility... 

In this Section, the reactions of sugar nitrates are compared with those of sugar sulfonate esters. 

Depending on their location on a sugar, sulfonates have very different reactivities. This is apparent, for example, in the behaviour of tosylates. The tosylate of the primary alcohol function can be substituted without difficulty, even in solvents which are not polar or aprotic. Substitution at positions 3 and 4 are only possible in DMF solution. Substitution at position 2 is absolutely impossible. On the other hand, it is often observed without problems at position 2 starting from a triflate or an imidazylate. These reactivity differences clearly appear in the triple substitution reaction of the tris-triflate P-D-galacto 7 J by benzoate (Alais and David 1990). The latter is prepared from the triol in 5 h at 0 C. It reacts quantitatively with tetrabutylammonium benzoate in toluene in 45 min at room temperature to give the D-gluco substitution product at C-4 and C-6. Heating for 1 h at 100 C then leads to the D-manno tribenzoate 74. 

Most of the publications in the field, however, have dealt with reactions in solution or with partially purified sulfonates. Only very recently have pure sulfonates been prepared and their properties investigated. The characteristics of two typical compounds, the acetaldehyde sulfonic acid and the glucose sulfonic acid, are discussed briefly below. The literature on the sugar sulfonates is reviewed in more detail by Gehman and Osman (1954). 

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