Hexonic 3-deoxy

Deoxy-n7 c -hexonic 3-Deoxy-flrfl /no-hexonic 3-Deoxy- cy/c -hexonic 3-Deoxy-/yjco-hexonic Allonic... 

Methyl 3,4,5,6-tetra-0-acetyl-2-deoxy-2-diazo-D-arabino-hexonate (84) has been irradiated in methanol and in 2-propanol.177 In methanol, the only photoproduct is the enol acetate 85 however, irradiation in 2-propanol results in formation of minor proportions (6%) of 85 and the alkene 86 (7%), but the major product is the deoxy sugar 87 (61%). The difference in reactivity of 84 in these two solvents is probably a reflection of the difference in the ability of methanol and 2-propanol to function as hydrogen donors when reacting with a carbene (see Scheme 31). In methanol, a 1,2-hydrogen atom shift to the divalent... 

Scheme 31.—Proposed Mechanism for Photochemical Reaction of Methyl 3,4,5,6-Tetra-0-acetyl-2-deoxy-2-diazo-D-arabino-hexonate (84).

Horton, D. and Philips, K.D., Diazo derivatives of sugars. Synthesis of methyl 2-deoxy-2-diazo-D-arahino-hexonate, its behaviour on photolysis and thermolysis, and conversion into a pyrazole derivative. Carbohydr. Res., 1972, 22, 151. 

In the presence of molecular oxygen, D-arabinose (82) is the major deamination product. D-tfrafeino-Hexos-2-ulose (79) is also formed, but the formation of 2-deoxy-D-hexonic acid (80) and 2-deoxy-D-ert/fhro-hexos-3-ulose (81) is suppressed. It has been suggested34 that the peroxyl radical derived from the W-centered radicals (78) may be, in part, the precursor of D-arabinose. A mechanism similar to the... 

The 3-deoxyaldonic acids (metasaccharinic acids) arise by alkaline treatment of monosaccharides, especially those substituted at C-3.288 They have also been obtained from (1 - 3)-linked oligo- and polysaccharides. The most common ones are 3-deoxy-D-n Z>o-hexonic acid (a-D-glucometasaccharinic acid, 109) and 3-deoxy-o-arabino-hexonic acid (jS-D-glucometasaccharinic acid, 110), which can most conveniently be... 

Deoxy-D-xy/o-hexonic acid (a-D-galactometasaccharinic acid, 111) can be prepared from D-galactose 289 the / -(d-lyxo) isomer can be isolated in smaller amounts from the mother liquors. 

Starting from D-galactono-1,4-lactone, 2-keto-3-deoxy-D-hexonic acids with either the D-erythro (119) or D-threo configuration (120) were obtained in only three steps.318 Epimerization at C-4 occurred during the base-catalyzed /1-elimination reaction on the galactonolactone derivative 136. 

W. M. Corbett, 2-Deoxy-D-nrai/no-hexonic acid from tri-O-acetyl-D-glucal, Methods Carbohydr. Chem., 2 (1963) 18-20. 

M. L. Wolfrom and N. E. Franks, 2-Deoxy-D-araWno-hexonic acid 6-phosphate and methyl 2-dcoxy-/i-D-tfraAwio-hexopyranosidc-4,6-monophcnylphosphatc, J. Org. Chem., 29 (1964) 3645-3647. 

H. B. Wood, Jr. and H. G. Fletcher, Jr., 2-Deoxy-D-ribose. VI. The preparation of derivatives of 3-deoxy-D-riAo-hexonic acid and 3-deoxy-D-araWno-hexonic acid therefrom. Some observations on the Kiliani synthesis, J. Org. Chem., 26 (1961) 1969-1973. 

The addition of PhSeCl to enone (—)-322 (obtained by saponification of 320) exclusively gives adduct 354. After oxidative elimination of the phenylseleno group and subsequent reduction, endo alcohol 355 is obtained in high yield. Applying the reaction sequence described in Scheme 13.92, 355 is converted into derivatives of 2,5-anhydro-3-deoxy-L-vy/6>-hexuronate 356 and 2,5-anhydro-4-deoxy-D-xy/o-hexonic acid 357 (Scheme 13.93). Inversion of configuration of alcohol 355 via... 

Gasparini, F, Vogel, P, Highly stereoselective total syntheses of 2,5-anhydro-3-deoxy- and 4-deoxy-D-hexonic acids and of the related deoxyadenosines-C, J. Org. Chem., 55, 2451-2457, 1990. 

Three structurally isomeric forms have been established for the six-carbon saccharinic acids. In the order of their discovery, these are the sac-charinic or 2-C -methylpentonic acids, the isosaccharinic or 3-deoxy-2-C -(hydroxymethyl)-pentonic acids, and the metasaccharinic or 3-deoxy-hexonic acids. Although none of these six-carbon, deoxyaldonic acids has been crystallized, six are known in the form of crystalline lactones (saccharins). All the possible metasaccharinic acids of less than six-carbon content have been obtained, in the form of crystalline derivatives, by the sugar-alkali reaction. Only one example of a branched-chain deoxyaldonic acid (the racemic, five-carbon isosaccharinic acid) of other than six-carbon content has been so obtained. The formation of saccharinic acids containing more than six carbon atoms remains to be explored. 

Deoxy-D-xyio-hexonic acid ( a -D -galactometasaccharinio acid)... 

Deoxy-D-a 2/io-hexonic acid ( a -D-galactometasaccharinic acid) was first detected as a product of the prolonged action of lime-water on lactose... 

Deoxy-D-l2/a o-hexonic acid ( /3 -D-galactometasaccharinic acid) was discovered by Kiliani and Sanda as a minor product of the n-galactose-al-kali reaction. Kiliani believed that this product was a new type of branched-chain saccharinic acid, and referred to it throughout subsequent publications as parasaccharinic acid. The evidence, provided both by his own work and that of Nef, that Kiliani s parasaccharinic acid contained, in fact, the epimer of a -D-galactometasaccharinic acid, is outlined on page 56. 

---