Hexaric acids

In a very thorough investigation of the reactions of hexaric acid lactones, and particularly dilactones, with sodium methoxide, F. Smith138,139 invariably obtained unsaturated products, at that time thought to be formed by isomerization and enolization. Hence, for alkyl D-glucofuranosidurono-6,3-lactones, also of bicyclic structure, similar reactions were believed24,25 to account for their unusual behavior in alkaline solutions. 

Some other water-soluble fully sugar-based polyamides have also been obtained from activated hexaric acids 28 and 29 and the 1,5-diamino-2,3,4-tri-O-methyl-pentitols (37 and 38) and a series of hydrophilic polyamides (PA-nSu) derived from these hexaric acids and noncarbohydrate alkylenediamines with even numbers of methylenes n = 4, 6, 8, 10, 12) has also been prepared [80]. 

There are four pentaric acids and ten hexaric acids ... 

Hexaric acids allaric (meso), formerly a//o-mucic galactaric (meso), formerly mucic D- and L-glucaric (l- and D-gularic), formerly D- and L-g/Mco-saccharic D- and L-mannaric, formerly D- and L-manno-saccharic D- and L-idaric, formerly D- and L-ido-saccharic and D- and L-altraric (d- and L-talaric), formerly D- and L-ta/o-mucic acid. 

Hexaric acids, III, 49, 50, 63 Hexasaocharides, from potato starch, III, 275... 

Recourse was then had to the direct oxidation of meso-inositol with alkaline potassium permanganate, and a hexaric acid was obtained which proved to be identical with allomucic acid prepared previously by Emil Fischer. Since the configuration assigned to this acid placed the four hydroxyl groups in a cis-cis-cis relationship, all the remaining configurations for meso-inositol save II are seen to be inapplicable. From the mother liquors of the oxidation mixture D,L-glucosaccharic acid was also isolated. This result, however, only showed that form IV was untenable. 

In 1941 Posternak studied scyllo-meso-inosose (see p. 65), a penta-hydroxycyclohexanone which had been obtained by Kluyver and Bo-ezaardt from the biochemical oxidation of meso-inositol. Cautious oxidation of scyllo-meso-inoaose with permanganate led Posternak to the isolation of a hexaric acid which he identified as n,L-glucosaccharic acid. Since, of the two forms II and V, only II can give an optically inactive inosose oxidizable to D,L-glucosaccharic acid, this evidence appeared to settle the configuration of meso-inositol. 

In 1942, however, Mrs. Gerda Dangschat announced the isolation of D,L-idosaccharic acid from the oxidation of a derivative of meso-inositol. Several months later Posternak published proof that his hexaric acid from the oxidation of inosose was actually n,L-idosaccharic acid and not n,L-glucosaccharic acid. Thus, by two separate paths meso-... 

Hexaric acids, 2,5-anhydro-, 54 Hexonic acid, 2-deoxy-D-arabino-, derivatives, 22... 

Overend and coworkers. The same conditions were required for the oxidation of 2-deoxy-D-ara mo-hexose to 2-deoxy-D-arabfno-hexaric acid this was isolated as the dilactone, in 27% yield. Attempts to oxidize methyl 2-deoxy-a, 3-D-eri/i/iro-pentofuranoside to the corresponding uronic acid were unsuccessful, owing to decomposition of the reaction product. ... 

The absolute configuration l(124/35) for natural w6o-quercitol was established by chemical correlation with 3-deoxy-D-a j/Jo-hexaric acid ( 3-deoxy-n-galactaric acid ) and with scyHo-quercitol (29). ... 

Our current major interest in aldaric acids is as monomers for polycondensation reactions with diamines to yield a broad class of polymers called polyhydroxypolyamides (PHPAs) or Hydroxylated Nylons (10). The original reports of examples of this class of polyamides were from the laboratory of N. Ogata and coworkers in Japan, beginning in the 1970s (11). More recent reports on these polymers have come from the laboratories of Hashimoto and coworkers (12) and those of author (13). Our general preparation of these polyamides, exemplified with a generic hexaric acid, is outlined in Figure 2. 

Some other fully sugar-based polyamides have been obtained from these activated hexaric acids and the 1,5-diamino-2,3,4-tri-(9-methyl-pentitols having the L-arabino andxyto configuration [101]. 

In addition to the aldonolactones, Szafranek etal (1974) have also studied lactones formed from deoxyaldonic, hexuronic and hexaric acids. These studies were carried out on glass capillary columns of SE-30, determining the concentrations of linear acid, 1,4-lactone and 1,5-lactone stmctures under equilibrium conditions and demonstrating the suitability of such columns in their separation. 

The diastereoisomers of each group (e.g. there are six isomers of hexaric acid) give closly similar spectra, but they can be differentiated by small differences in ion intensities. The diastereoisomers 5- and 6-carbon atom deoxy acids can be identified in the same way, although less readily than the aldaric acids (Petersson, 1972b). 

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