SYNTHESIS OF 3-DEOXY-2-OCTULOSONIC ACID-DERIVATIVES AND CHARACTERIZATION OF THEIR 3-DEOXYOCTITOLS

The diethyl dithioacetals of D-altrose, D-idose, and D-talose were used to synthesise the respective O-benzyl aldehydo-sugars as intermediates for the synthesis of 3-deoxy-D-glycero-D-gluco/manno-, 3-deoxy-D-glycero-L-gulo/ido-, and 3-deoxy-D-glycero-L-allo/altro-octonate derivatives, respectively. After reduction and deprotection, the respective 3-deoxyoctitols were obtained. For the synthesis of 3-deoxy-D-glycero-L-galacto/talo-octitol, 2,3:5,6-di-O-isopropylidene-D-gulono-1,4-lactone was transformed by reduction and selective oxidation at C-1 to the aldehydo-D-gulose, from which the 3-deoxy-D-glycero-L-galacto/talo-octonate was synthesised. Carboxyl- and carbonyl-reduction and deprotection gave the 3-deoxyoctitol. The 3-deoxyoctitols were characterised by GLC and GLC-MS in the acetylated and methylated form. The data presented here and the data published earlier [T. Krulle, O. Hoist, H. Brade, and R.R. Schmidt, Carbohydr Res., 247 (1993) 145-158] showed that methylated 3-deoxy-D-glycero-n-galacto/talo-octitol can be distinguished by GLC from the other 3-deoxy-D-octitols and thus allows the identification of the manno configuration of 3-deoxy-D-manno-octulosonic acid (Kdo) in natural products such as the lipopolysaccharides of different Gram-negative bacteria, where Kdo is a generally occurring constituent.