2782-04-9

Quantitative correlative 1H-13C NMR has long been discussed as a potential method for quantifying the components of complex reaction mixtures. Here, we show that quantitative HMBC NMR can be applied to understand the complexity of the catalytic oxidation of glucose to glucaric acid, which is a promising bio-derived precursor to adipic acid, under aqueous aerobic conditions. It is shown through 2D NMR analysis that the product streams of this increasingly studied reaction contain lactone and dilactone derivatives of acid products, including glucaric acid, which are not observable/quantifiable using traditional chromatographic techniques. At 98% glucose conversion, total C6 lactone yield reaches 44%. Furthermore, a study of catalyst stability shows that all Pt catalysts undergo product-mediated chemical leaching. Through catalyst development studies, it is shown that sequestration of leached Pt can be achieved through use of carbon supports.

The presently claimed invention is directed to a process for preparing D-glucaro-6,3-lactone from a salt of D-glucaric acid.

Uronate dehydrogenase from Agrobacterium tumefaciens (AtUdh) belongs to the short-chain dehydrogenase/reductase superfamily and catalyzes the oxidation of D-galacturonic acid and D-glucuronic acid with NAD+ as a cofactor. We have determined the crystal structures of an apo-form of AtUdh, a ternary form in complex with NADH and product (substrate-soaked structure), and an inactive Y136A mutant in complex with NAD+. The crystal structures suggest AtUdh to be a homohexamer, which has also been observed to be the major form in solution. The monomer contains a Rossmann fold, essential for nucleotide binding and a common feature of the short-chain dehydrogenase/reductase family enzymes. The ternary complex structure reveals a product, D-galactaro-1,5-lactone, which is bound above the nicotinamide ring. This product rearranges in solution to D-galactaro-1,4-lactone as verified by mass spectrometry analysis, which agrees with our previous NMR study. The crystal structure of the mutant with the catalytic residue Tyr-136 substituted with alanine shows changes in the position of Ile-74 and Ser-75. This probably altered the binding of the nicotinamide end of NAD+, which was not visible in the electron density map. The structures presented provide novel insights into cofactor and substrate binding and the reaction mechanism of AtUdh. This information can be applied to the design of efficient microbial conversion of D-galacturonic acid-based waste materials.

(Chemical Equation Presented) Calcium D-glucarate was converted into D-glucaro-1,4:6,3-dilactone on 32-g, 1-kg, and 22-kg scale, using azeotropic distillation with methyl isobutyl ketone to drive the dehydration. The crystalline product was g99.5% pure by

A simple procedure for the preparation of stereoregular polyhydroxypolyamides, i.e., head,tail hydroxylated nylons, derived from D-glucaric acid and alkylenediamines is described. Sodium D-glucarate 6,3-lactone was made in two steps from monopotassium D-glucarate by way of D-glucaro-6,3-lactone. Methanol insoluble salt of sodium 6-[N-(aminoalkyl)]-D-glucaramide monomer precursors were conveniently prepared by refluxing methanol solutions of even-numbered C2 to C12 aliphatic diamines with insoluble sodium D-glucarate-6,3-lactone. Each of the resulting salts was esterified/lactonized at the C-1 carboxylate terminus with HCl/methanol, and the products were made basic to give the corresponding free base amino acid ester/lactone mixture. The latter spontaneously underwent self-polymerization to give the target polyamides. An important feature of this general procedure for stereoregular polyamides from chiral D-glucaric acid is that it does not require any carbohydrate hydroxyl group protection/deprotection steps.