IV-Acetylneuraminic acid

Table 4. IV-Acetylneuraminic Acid Aldolase Catalyzed Preparative Aldol Additions with Pyruvate...

Ryan DM, Ticehurst J, Dempsey MH (1995) GG167 (4-guanidino-2,4-dideoxy-2,3-dehydro-iV-acetylneuraminic acid) is a potent inhibitor of influenza virus in ferrets, Antimicrob Agents Chemother 39 2583-2584... 

E. Schreiner, R. Christian, and E. Zribal, Synthesis of 9-deoxy-, 7,9-dideoxy-, and 4,7,9-trideoxy-iV-acetylneuraminic acid and their behaviour towards CMP-sialate synthase, Liebigs Ann. Chem. p. 93 (1990). 

A. Marra and P. Sinay, Stereoselective synthesis of 2-thiogIycosides of IV-acetylneuraminic acid, Carbohydr. Res. 187 35 (1989). 

The most representative example of this family is iV-acetylneuraminic acid (Neu5Ac 1 Scheme 2), a nine-carbon sugar, ubiquitous in the animal kingdom and especially... 

Cytidine triphosphate is necessary to the activation of iV-acetylneuraminic acid (see Section V,3). Its preparation39-69 is given in Scheme 17. The not... 

Condensation [270] of the chloride (370) with the allyl lactoside (397) as described above for the preparation of (392) gave a 6 % yield of the P-linked iV-acetylneuraminic acid derivative (on the 3 -hydroxyl group) and none. of the a-linked material. The product was acetylated and deallylated to give (398) and this was converted into the trichloroacetimidate (399) which was condensed with the 3-O-benzoylceramide to give the P-iV-acetyl-neuraminyl derivative of hematoside ( epi-hematoside ). 

In order to try to overcome some of the problems associated with chemical synthesis of oligosaccharides containing N-acetylneuraminic acid, Sabesan and Paulson [277] have used a combination of chemical and enzymatic methods using purified sialyl-transferases in the presence of CMP-iV-acetylneuraminic acid and synthetic acceptor molecules to give sialyl derivatives of oligosaccharides which were characterised by NMR. Thus, methyl P-D-galactopyranoside, methyl P-D-lactoside and iV-acetyl-... 

Thiem and Treder [278] have used immobilised enzymes [216] for the separate syntheses of Af-acetyllactosamine and CMP-iV-acetylneuraminic acid. These were allowed to react in solution in the presence of the sialyltransferase to give the 6 -N-acetylneuraminyl glycoside on the 50 pmol scale. 

The process yields an interesting synthon for the synthesis of higher sugars with complete stereocontrol. Higher sugars play important roles in many biological processes. Prominent examples are KDO (3-deoxy-D-manno-octulosonic acid), a component of bacterial liposaccharides [37], and iV-acetylneuraminic acid, which is a crucial component of human and animal glycoconjugates [38,39]. In addition, derivatives of iV-acetylneuraminic acid show remarkable antiviral properties [40]. 

The second pathway for the formation of 3-deoxyulosonic acids is, at present, represented only by the condensation of pyruvate with iV -acetyl-n-mannosamine to form a nonulosaminic acid (iV-acetylneuraminic acid). - This reaction is readily reversible, but the point of equilibrium is 90 per cent toward degradation and 10 per cent toward synthesis of the iV-acetyl-neuraminic acid. ... 

Piperidinecarboxylic acids, analogs of IV-acetylneuraminic acid, were synthesized by the re-gioselective intramolecular cycloadditions of the suitably substituted optically active azidoalke-nes 133,134. The best results were obtained when the substrate contained protected hydroxy functions. In the cyclization of tert-butyl 2-azido-6-heptenoates 17133, the diastereoselectivity is rationalized by analyzing the steric interactions in the transition states leading to the cycloadducts from different conformations of the azidoalkene. The cycloaddition took place on the / e-face of the alkenyl group in the chair transition state containing all axial substituents. 

Dufner G, Schworer R, Muller B, Schmidt RR. Base- and sugar-modified cytidine monophosphate iV-acetylneuraminic acid (CMP-Neu5Ac) analogues - synthesis and smdies with (2-6)-sialyltransferase from rat Uver. Eur. J. Org. Chem. 2000 1467—... 

Studies of hetero Diels-Alder condensation that used enantiopure substituted aldehydes found that the catalyzed additions had a high and predictable stereoselectivity [231]. The synthesis of iV-acetylneuraminic acid 130 [232] from diene 127 and (S)-selenoaldehyde 128, which is shown below, illustrates this point (O Scheme 44). 

This method has also been applied to a high-yielding stereoselective synthesis of C-linked IV-acetylneuraminic acid (Neu5Ac)-containing disaccharides [92] starting from either the 2-p)ridyl (phenyl) sulfones 189 and 190 or the anomeric chloride 191 (O Scheme 40). 

The use of monosaccharide-based arrays to detect bacterial toxins, viruses and bacteria has been reported [219]. Arrays of IV-acetyl galactosamine and IV-acetylneuraminic acid derivatives were immobilized and were probed with fluorescently labeled bacterial cells and protein... 

In addition to glucose and galactose and their amino derivatives, glycoproteins contain mannose, L-fucose, and IV-acetylneuraminic acid (NANA). 

Fig. 29. Optimum pH of hydrolysis of human placental alkaline phosphatase by neuraminidase. The liberated sialic acid was measured by the Warren-thiobarbiturate procedure, using iV-acetylneuraminic acid as the standard (G6a).

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