Automated solution-phase synthesis of oligosaccharides via iterative electrochemical assembly of thioglycosides.

A new iterative one-pot sequential method for the solution-phase synthesis of oligosaccharides has been devised on the basis of the electrochemical oxidation of a propagating thioglycoside terminus to generate the corresponding triflate, followed by the reaction with a thioglycoside building block having a free hydroxyl group. A practical automated synthesizer was developed for the method and was effectively used for assembling up to six thioglycoside building blocks to synthesize partial structures of poly-ß-D-(1-6)-N-acetylglucosamine.

Electrochemical generation of 2,3-oxazolidinone glycosyl triflates as an intermediate for stereoselective glycosylation.

Glycosyl triflates with a 2,3-oxazolidinone protecting group were generated from thioglycosides by low-temperature electrochemical oxidation. The glycosyl triflates reacted with alcohols to give the corresponding glycosides ß-selectively at low temperatures. However, α-selectivity was observed in the absence of base at elevated reaction temperatures. In situ generated triflic acid promotes the isomerization of ß-products to α-products.

Glycosyl sulfonium ions as storable intermediates for glycosylations.

Glycosyl sulfonium ions, which serve as persistent glycosyl cation equivalents, were prepared by the addition of diorganosulfides to an electrochemically generated glycosyl triflate. Low-temperature and variable-temperature NMR studies were performed to reveal the structure, stability, and reactivity of glycosyl sulfonium ions. The glycosyl sulfonium ions could be used as storable intermediates for reactions with various glycosyl acceptors including thioglycosides to give the corresponding disaccharides.

[A case of histiocytic necrotizing lymphadenitis showing focal lymph nodes swelling in the abdomen].

A case was 23 years old woman. She came to our hospital with complain of continuing fever after common cold and mass like an egg was touched in right lower abdomen. No other surface lymph node was swelling. Abdominal US, CT and MRI showed that the mass was existed in the front of the psoas muscle and the maximum diameter of it was 6 cm in which necrotizing lesion was recognized. The size of the lymph node became smaller slowly but we could not perfectly exclude malignant disease, we examined needle biopsy for the diagnosis. The histopathological findings showed the histiocytic necrotizing lymphadenitis (HNL). HNL usually appears in the neck area, but in this case it was detected only in the abdomen. This case was very rare and we reported.