Paratose synthesis

An important step in the synthesis of paratose (3,6-dideoxy-n-rtfoo-hexose) involved the conversion of methyl 3-chloro-3-deoxy-/8-D-allopyranoside into methyl 3,6-dichloro-3,6-dideoxy-/8-D-allo-pyranoside in 33% yield.359... 

E. H. Williams, W. A. Szarek, and J. K. N. Jones, Synthesis of paratose (3,6-dideoxy-D-rifw-hexose) and tyvelose (3,6-dideoxy-D-orahmo-hexose), Can. J. Chem. 49 796 (1971). 

C. Fouquey, J. Polonsky, and E. Lederer, Synthesis of three 3,6-dideoxyhexoses. Determination of the structure of the natural sugars tyvelose, ascarylose, and paratose, Bull. Soc. Chim. Fr. p. 803 (1959). 

Starting from 1,5-anhydro-2,3,4-tri-0-benzoyl-6-deoxy-D-ura >/ o-hex-1 -enitol (48), an unusual approach to the synthesis of disaccharides of serogroup A and D has applied the allylic rearrangement glycosylation procedure of Ferrier [127] to obtain an a-D-< rj//zTO-hex-2-enopyranosyl residue in the disaccharide 49a. Reduction of the 2-enopyranose double bond gave both the paratose (ribo) 49b and tyvelose (arabino) 49c products [28]. 

Synthesis of D-epiallomuscarine, a 2,S-anhydro-3,6-dideoxyaldonic acid derivative, is detailed in Chapter 23. Paratose (3,6-dideoxy-D-r/i o-hexose) has been prepared from the 3-deoxy compound (13) by selective hydrolysis, tosylation at the primary position, and reduction using lithium aluminium... 

Whitesides and coworkers have carried out a comparison of enzymic and chemical routes to CTP, GTP and UTP on a 10-gram scale. They concluded that CTP and GTP were best made enzymically, and UTP by reaction of CTP with nitrous acid. The triphosphates were then employed for the enzymic synthesis of UDP-Glucose, UDP-Glucuronic acid, and GDP-Mannose.i94 Cytidine diphosphate sugars have been prepared from the 3,6-dideoxyhexoses paratose and abequose,193 and all four nucleoside diphosphate sugars of 6-sulpho-a-D-quinovose have been synthesized for studies of sulpholipid biosynthesis in chloroplasts.196 The stable analogue (138) of CMP-KDO has been prepared by a triester approach, but was only a weak inhibitor of KDO incorporation into lipopolysaccharides.197 A reference to acetylated forms of UDPGlc is mentioned in Chapter 7. 

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