Carbohydrates nitro group

If d carbohydrate already contains a nitro group, the nitro-bearing carbon atom can become the nucleophilic center for the conphng of two monosaccharide units fsee Section 3 2 2 Snami and coworkers have used this method for the synthesis of andbiodcs bearing sugars " A typical example is presented in Eq 3 63 "... 

In the last twenty years, nitro sugars became powerful chemical tools on account of their usefulness for the construction of carbon-carbon bonds prior to the transformation of the nitro group into a variety of other chemical functionalities. As a result, a diverse range of funcionalized carbohydrates and other derivatives as carbasugars, cyclitols and heterocycles have been prepared. 

Nitroolefins are good Michael acceptors and have been used as such in the carbohydrate series. One advantage of this approach would be the subsequent transformation into branched-chain amino sugars after reduction of the nitro group. Baer has reported the... 

Another method of seemingly general applicability to carbohydrates was used by Coat et al. to conjugate uridine to proteins. The isopropyli-dine derivative was allowed to react withp-nitrobenzoyl chloride to yield the 5 ester. Removal of the isopropylidine protecting group and hydrogenation of the nitro group made it possible to link the uridine derivative to the protein by a diazotization reaction. 

Finally, Table III presents the data for the p-nitrophenylgalactose and the p-nitrophenylglucose pairs. The addition of a nitro group to the phenyl ring did not only enlarge it, but also enhanced the overall dipole moment exerted by the aglycone on the carbohydrate residue. This results in a much more extensive overall fragmentation. 

Cleavage of nitro groups from carbohydrate nitrates... 

Nitro groups in the furan ring are reduced easily by various biochemical processes . Nitrofurazone can function as an electron acceptor in a number of bacterial dehydrogenase systems involved in carbohydrate metabolism. 

The nitrocellulose polymer substrate was a fully nitrated derivative of cellulose, in which the free hydroxyl groups are substituted by nitro groups, and is thus hydrophobic in nature. Researchers have shown that the immobilization of proteins on nitrocellulose surfaces rehes on hydrophobic interactions. However, polysaccharides, being rich in hydroxyl groups, are hydrophilic in nature (42,61). The molecular forces for the carbohydrate-nitrocellulose interaction remain to be characterized, but it has been suggested that the three-dimensional (3D) microporous configuration of the nitrocellulose on the slides and the macropolymer characteristics of polysaccharides play important roles for the stable immobilization of many polysaccharides on the nitrocellulose surface. The polysaccharide molecules immobilized onto the nitrocellulose film are in a nonsite-specific format (Fig. 3). 

Nitrogen dioxide has been recommended, in place of the customary nitric acid, as a convenient and inexpensive oxidising agent for the production of oxalic acid from carbohydrates. D-Glucose and D-fructose have been employed for the reduction of the nitro groups of some nitroanilines, such as compounds (54), to amino groups. ... 

Back-scattered Raman optical activity spectra were measured in the 7(X)-15(X) cm region for a range of carbohydrates in aqueous solution. Features of the spectra were identified that appear to be characteristic of the stereochemistry of the sugars. The i.r. spectra of methyl 2,3-di-, 2,3,6-tri- and 2,3,4,6-tetra-O-nitro-p-D-glucosides were examined in the 30-7(X) cm range, and interpretation of the bands observed was given in terms of the conformation and location of the nitro-groups and of crystal lattice vibrations. ... 

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