Sugars unique structures

The general chemistry of branched-chain sugars has not been the subject of systematic investigation, mainly because of the scarcity of these compounds. Nevertheless, the totality of reactions employed for elucidating the unique structures of these compounds constitutes a body of valuable information which is basic for future developments. Lucid articles on the chemistry of streptose, by Lemieux and Wolfrom,1 and of apiose, by Hudson, have appeared in earlier volumes of this Series the present article will therefore not include information on these two sugars, except as regards comparison with other sugars and in reference to new developments. 

The carbohydrate part of various cardiac glycosides can be mono-, di-, tri-, and tetrasaccharide, and the aglycon (genin) is a steroid with certain unique structural characteristics. The main purpose of sugar residues is evidently to facilitate solubility of... 

Chemically, novobiocin has a unique structure among antibiotics. though, like. several others, it possesses a glyeosidie sugar moiety. The sugar in novobiiK in. devoid of its eurba-... 

CWM was then extracted sequentially with water at 80 and with ammonium oxalate at 80, delignified with acidified sodium chlorite at 70 , and then further extracted with M and 4M sodium hydroxide. The crude polysaccharide extracts were likewise analyzed for constituent sugars and uronic acid (Table II). In order to obtain defined polysaccharide fractions the following separations were attempted. Polysaccharide fraction A was separated by ion-exchange chromatography on diethylaminoethyl(DEAE)-Sephadex A-50 and the neutral fraction afforded a virtually pure arablnan ( in Scheme 2) after selective precipitation with cetyltrimethylammonium hydroxide (7 ). Linkage analysis by methylation confirmed that this arablnan was of the highly branched type associated with pectins for which the representative, but not unique, structure (J ) may be advanced. 

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