Galactonic acid 3.6- anhydro

DL-galactonic acid (39). 1,4-Anhydro-DL-talitol (3,6-anhydro-DL-altritol) (40) gave 2-0-(carboxymethyl)-DL-threaric acid (41) and 1,4-anhydro-D-mannitol (42) gave 2-0-(carboxymethyl)erythraric acid (43). 

Jones and Peat23 separated methylated agar into an acidic and a neutral fraction by precipitation methods. From the hydrolyzate of the acidic fraction they isolated 2,4,6-trimethyl-D-galacto e, 2,3,4,6-tetra-methyl-D-galactose, and 3,6-anhydro-2,5-dimethyl-L-galactonic acid (XII, as the crystalline amide of m. p. 173°). The structure assignment of XII was made on the following basis. The rotation of its amide, [a]D —75.7°... 

Percival and Thomson44 obtained a mixture of disaocharide esters from which, on hydrolysis and derivatization, they isolated 2,3,4,6-tetramethyl-D-galactose anilide and a mixture of methylated acids. From these acids they obtained 3,6-anhydro-2,5-dimethyl-L-galactonic acid, the structure of which was determined by almost the same means as those employed by Jones and Peat.23 On methanolysis of hexamethylagarobiose, Araki28 isolated 3,6-anhydro-2,5-dimethyl-L-galactose dimethyl acetal (XIII),... 

L-Galactonic acid, I, 69 and calcium salt, I, 70 —, 3,6-anhydro-2,4-dimethyI-, methyl ester, II, 77... 

Heating 6-bromo-6-deoxy-D-galactono-1,4-lactone or -D-galactitol in water yields 3,6-anhydro-D-galactonic acid and 1,4-anhydro-L-galactitol (3,6-anhydro-D-galactitol) respectivdy. ... 

Some pseudo-C-nucleosides such as (97) have been prepared from diisopropylidene glucose. 156 rti-0-acetyl-2,6-anhydro-L-galactonic acid (98) is available from D-galactuionic acid in three steps, and has been used to prepare some p-L-lyxopyranosyl C-nucleosides such as (99). 157... 

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