Cyclitol analogs

Figure 4.2.17 Special natural monosaccharide derivative and cyclitol analogs.

Simple analogs of an aminoglycoside antibiotic, 2,6-dideoxy-4-0- (671) and -5-0-(2,3-dideoxy-2-fluoro-o -D-r/Z>o-hexopyranosyl)streptamine (672) were prepared by coupling of tri-O-acetyl-2-fluoro-D-glucal (666) with cyclitol derivatives 668 or 667 (through 669 and 670) as shown. 

The naked sugars of the first generation (319, 320, 321, (+)-322, (—)-322) are useful chirons for preparing all kinds of rare sugars derivatives [180] and analogs such as C-linked disaccharides [181]. They have been converted into conduritols, cyclitols and carbahexose derivatives [174,182]. The bicyclic ketones can also be converted into their enoxysilanes and then cleaved by ozonolysis. Depending on the workup conditions, 2,5-anhydrohexaldaric acid or 2,5-anhydrohexonic acid derivatives can be readily prepared in both enantiomerically pure forms [183]. 

Cyclitol, carbasugar and modified D-galactose analogs of KRN7000 ... 

The diolization of the double bond in this series of reactions appears to be analogous to the diolization of the double bond of conduritol, a cyclohexene-tetrol (see Cyclitol section). When the hexenetetrol above was oxidized directly, the hydroxyls entered cis to the hydroxyls already present and allitol was the chief product similarly, aHo-inositol was obtained on oxidation of o-isopropylideneconduritol diacetate with potassium permanganate. On the other hand, for the two fully acetylated tetrols (acyclic and cyclic), the hydroxyls entered trans to those already present, giving galactitol and mwco-inositol tetraacetate, respectively (p. 284). 

The NHase/amidase system in R. erythropolis A4 was also used to transform cyano cyclitols into their carboxyhc acid analogs [21, 22]. As these transformations were coupled to lipase-catalyzed hydrolytic reactions, they are described in detail in the section focused on artificial cascades (see the following paragraphs). 

Tashiro, T, Nakagawa, R., Hirokawa, T, Inoue, S., Watarai, H., Taniguchi, M., and Mori, K. (2009) RCAI-37, 56, 59, 60, 92, 101, and 102, cyclitols and carbasugar analogs of KRN7000 Their synthesis and bioactivity for mouse lymphocytes to produce Thl-biased cytokines. Bioorg. Med. Chem., 17, 6360-6373. 

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