D-Mannaric acid

Aldaric acids or their derivatives undergo ready epimerization in pyridine. Alkaline treatment of 4-O-methyl-D-glucuronic acid in the presence of air affords 4-O-methyl-D-glucaric and -D-mannaric acids as well as lower O-methylaldaric acids.262 The two diastereo-isomeric 3-deoxy-2-C-(hydroxymethyl)pentaric acids obtained from... 

Proof of the structure of the uronic acid was obtained by Hirst, Jones and Jones,46 who isolated the methyl glycoside methyl ester by methyla-tion of the products from the graded methanolysis of alginic acid. The tri-O-methyl-D-mannuronic acid was converted to the diamide of 2,3,4-tri-O-methyl-D-mannaric acid, which had previously been prepared from... 

The acetylation of 2-(D-ara6o-tetrahydroxybutyl)benzimidazole is reported to yield a tetraacetate 7 2-(D-paiacto-pentahydroxypentyl)-benzimidazole, on the other hand, apparently forms a hexaacetyl derivative,30 and the dibenzimidazole from D-mannaric acid, which contains four hydroxyl and two imino groups, forms a hexaacetyl derivative.22,28 It is not clear from these isolated cases whether N-acetylation as well as O-acetylation is to be expected or not. 

The coordination behavior of molybdenum(VI) with D-mannaric acid 64 is similar to that with galactaric acid two molybdenum atoms are bonded either by the two a-alkoxidocarboxylato moieties of fourfoldly deprotonated D-mannaric acid or by the aikoxido functions of the C1-C3 subset and the C4—C6 subset, respectively, of entirely deprotonated D-mannaric acid. Due to the f/ireo-conflguration of the central diol residue, a threo complex is established in neutral solutions with a molar ratio of Mo ligand of 4 1 instead of an erythro complex which was observed with galactaric acid (compare structure 20 and 14 (O Fig. 2), respectively) [75]. The latter threo complex as well as a complex with the a-alkoxidocarboxylato moieties as chelation sites is also formed by tungsten(VI) [76]. 

The deamination reaction of 2-amino-2-deoxy aldonolactones is also of interest. 2,5-Anhydro-D-mannaric acid has been obtained from the treatment of 2-amino-2-deoxy-D-mannonolactone, epichitosaminic lactone, with nitrous acid and subsequent oxidation of the product with nitric acid. This indicates that the reaction proceeds with a net retention of configuration, as for the corresponding free acid discussed later (p. 56). Similar treatment of 2-amino-2-deoxy-D-idonolactone, d-dextro-xylo-hexosaminic lactone, provides 2,5-anhydro-D-gularic acid, which is the epimer of the product derived from the free acid. " ... 

Similarly, D-mannaric acid 1,4 6,3-dilactone (12) gave, under the same conditions, the corresponding O-methylated, unsaturated esters 13 and 14. 

Typically, condensations to polyamide (II), are carried out between an activated, i.e., esterified (diester, ester/lactone, dilactone) form of the aldaric acid (I), and a primary diamine in a polar protic solvent such as methanol at room temperature. Under those conditions any starting single ester form of a five or six carbon aldaric acid is rapidly converted to an equilibrium mixture of acyclic diester and ester/lactone forms. Dilactone, if formed at all, is present in only small amounts. The starting monomer esterified form(s) of the aldaric acid differ from one acid to an other. For example, the monomers of choice for L-tartaric acid (1) and weso-galactaric acid (4) are simple diesters, while for D-glucaric acid suitable monomers are ester/lactones, dilactone, or even the entire alcohol esterified mixture (10). Xylaric acid is also conveniently polymerized as its esterification mixture while the D-mannaric acid monomer is the 1,4 6,3-dilactone (13a). 

Kiely D.E., Chen. L., Lin T.-H., Synthetic poly hydroxy polyamides from galactaric, Xylaric, o-glucaric, and D-mannaric acids and aLkylenediamine monomers-Some comparisons, J. Polym. Sci. Part A Polym. Chem., 38, 2000, 594-603. 

Tetra-O-methyl-D-mannaric acid, M-23 L-Threaric acid, T-12... 

Step 4—Since both D-glucaric and D-mannaric acids (E and F) are optically active, the configuration of neither of them can possess end-to-end symmetry hence the OH on C-4 must be on the right... 

Oxidation of D-mannaric acid l,4 6,3-dilactone with potassium permanganate furnished the dienone (287), which was transformed into a series of pyrrole and other derivatives. The hydroxy-groups at C-2 and C-5 of D-mannaric acid l,4 6,3-dilactone could also be oxidized in turn to give (288) and (289) treatment of these products with hydrogen bromide in acetic acid-acetic anhydride introduced geminal bromo and acetyl groups at C-2 and at C-5, respectively." ... 

The problem now resolved into determining the configuration of C-4 for structures H and J (reaction 2.5). Fischer reasoned that because both D-glucaric acid and D-mannaric acid were optically active, the configuration of the OH group at C-4 had to be to the right (structure K below) because, if it were to the left, the aric acid of structure H would be optically inactive due to intramolecular symmetry (structure L, below). 

---