Sugar derivatives

Sugar derivatives. Sugar economics. Special sugars. 

Wort. Wort is the Hquid drained off the mash tun containing maltose, a grain sugar derived from the conversion of starch during the mashing process by the action of the organic enzyme, maltase, found in badey malt. 

Various substituted N-hiomo- and A/-chloroureas have also been prepared (97). These compounds are useful for synthesis of oxazoUdinones, and also hydrazine, hydrazo, and azo compounds. A/-Bromourea [51918-81 -1] is useful for selective oxidation of sugar derivatives (98). 

BAER FISCHER Amino sugar synthesis Synthesis of 3-nrtro and 3-amlno sugars by aldol condensation of sugar-derived dlaktehydes with nilroalkanes. 

IV-Acetylglucosamine and IV-Acetylmuraniic acid Sugar derivatives in the peptidoglycan layer of bacterial cell walls. 

Note The reagent can be employed on sihca gel, kieselguhr. Si 50 000 and cellulose layers. At room temperature sugars and sugar derivatives react at different rates depending on the functional groups present [1], e.g. ketoses react more rapidly than aldoses. It is possible to differentiate substance types on this basis [1, 3]. 

The condensation reactions of aromatic o-diamines and sugars and sugar derivatives have been studied in detail and quinoxaline derivatives have been prepared recently from osones, osonehydrazones, and dehydro-L-ascorbic acidd ... 

Another deviation from the normal displacement reaction of primary tosylates occurs in nucleoside derivatives (39, 81) where cyclonucleosides and anhydronucleosides are formed by participation of a nitrogen atom (as in purine nucleosides) and oxygen atom (as in pyrimidine nucleosides ), respectively. Iodonucleosides can result from these reactions only if these cyclic compounds are prone to attack by iodide ion. Several new examples of unexpected reactions during the solvolysis of sulfonate esters in sugar derivatives have been recorded in the past few years (2, 4,5,7,15,44,62,63,94). 

Perhaps the earliest report of the replacement of a sulfonate ester attached to a secondary carbon atom in a sugar derivative was that of Helferich (53). Under quite drastic conditions (sodium iodide in acetone, 105°C., 72 hours, sealed system) the 4-mesylate derivative 9 was converted into a crystalline 4-deoxy-4-iodo sugar derivative 10 in 46% yield. Although the position of the iodine atom was established, the configuration at C-4 was not known. 

An attractive feature in this reaction is the possibility of direct substitution and formation of unblocked sugar derivatives containing one or more chlorodeoxy function in essentially two steps. Another facet is the formation of methyl 4,6-dichloro-4,6-dideoxy-hexosides from certain methyl glycosides in one step. Such compounds could be valuable intermediates in the synthesis of dideoxy and diamino sugars of biological importance. 

The presence of hydroxyl groups in the benzylidene sugars does not interfere with the reaction and by-products are usually minor. Suitable solvents other than carbon tetrachloride, include benzene and tetra-chloroethane. Epoxide, amide, and other commonly encountered functionalities in sugar derivatives are unaffected under the reaction conditions. The corresponding 6-bromo-4-benzoates are valuable intermediates... 

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