3.6- Dideoxy sugars paratose

The biologically important sugars paratose (3,6-dideoxy-D-nho-hexose) and tyvelose (3,6-dideoxy-D-arafctno-hexose) have also been conveniently prepared203 by routes involving reductive dechlorination by hydrogenation over Raney nickel catalyst these 3,6-dideoxy-... 

Bacterial surface polysaccharides contain a variety of dideoxy sugars. The four 3,6-dideoxy sugars D-paratose (3,6-dideoxy-o-glucose), u-abequose (3,6-dideoxy-D-galactose), D-t5rvelose (3,6-dideoxy-o-mannose), and i-ascarylose (3,6-dideoxy-L-mannose), whose sfrucfures are shown in Fig. 4-15, arise from CDP-glucose. This subsfrafe is first converted, in reactions parallel to the first three steps of Eq. 20-10, to... 

Some of the rare sugars that have been prepared by way of chloro-deoxy derivatives are 4,6-dideoxy-3-0-methyl-D-xyZo-hexose (D-chal-cose), 3,6-dideoxy-D-n foo-hexose (paratose), 3,6-dideoxy-D-arafcmo-hexose (tyvelose), methyl 2,3-dideoxy-/3-D-glr/cero-hex-2-enopyrano-sid-4-ulose, and certain aminodeoxy sugars. 

A fifth sugar of this series, paratose, was found in the specific polysaccharide of Salmonella paratyphi A. This sugar was identified as 3,6-dideoxy-D-rtbo-hexose by comparison with a sample synthesized from 3-deoxy-D- glucose as described above. A member of the fourth configuration, 3,6-dideoxy-L-lj/xo-hexose, has now also been synthesized, but neither the D nor the l form of this configuration has yet been found in natural products. 

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