2-Keto-D-gluconate

Ameyama M. 1982. Enzymatic microdetemtination of D-glucose, D-fructose, D-gluconate, 2-keto-D-gluconate, aldehyde, and alcohol with memhrane-hound dehydrogenases. Meth Enzymol 89 20-29. 

Oxidation of Isopropylidene Derivatives of Ketose Sugars. Whenever isopropylidene derivatives can be obtained in which all groups except the primary alcoholic grouping at Cl are blocked this method is undoubtedly the best. It may be illustrated by reference to the preparation of 2-keto-D-gluconic acid from D-fructose.14... 

The process of lactonization and enolization of 2-keto esters under the influence of alkaline reagents has also been applied to the production of analogs of L-ascorbic acid containing a six-membered ring structure.22 For example, methyl 3,4,6-trimethyl-2-keto-D-gluconate (XLI) is treated... 

There is good evidence for the presence of a five-membered ring in D-araboascorbic acid (XXXIX). This analog of L-ascorbic acid, prepared by method 2 (page 87) from methyl 2-keto-D-gluconate shows the same chemical properties and the same absorption characteristics as L-ascorbic acid. Titration of XXXIX with diazomethane affords, as in the case of L-ascorbic acid, a 3-methyl derivative LXXXII which upon further action with diazomethane gives rise to the 2,3-dimethyl-D-arabo-ascorbic acid (LXXXIII)3 ... 

Moreover, the compound (LV) obtained from the reaction of 2-keto-D-gluconic acid with o-phenylenediamine28 has been dehydrated to give a compound which Maurer erroneously described as LYI. In this case, also, the process of dehydration has been shown to be equivalent to that just described for compound L. The product obtained by interaction of 2-furyl-... 

D-arabino-Hexuionic acid ( 2-Keto-D-gluconic acid ) O H H HO hoh2 c—c—c—c—c—c ooh HO HO H red seaweed, Chondrus crispus ( )... 

CgHgOr Ca-SHjO Calcium /3-D-arafoino-hexulosonate trihydrate (calcium 2-keto-D-gluconate trihydrate)10 P2i2i2i Z = 4 Dx = 1.743 R = 0.094 for 2,235 intensities (film measurements). There are two symmetry-independent, pyranoid molecules having very similar, distorted 5 conformations. The ring tor-... 

El- glucose dehydrogenase E2- gluconic acid dehydrogenase E3- 2-keto-D-gluconic acid dehydrogenase E4- 2,5-diketo-D-gluconic acid reductase... 

J. Geigert, S. L. Neidleman, D. S. Hirano, B. Wolf, and B. Panchar, Enzymic oxidation of D-araWrco-hexos-2-ulose (D-glucosone) to D-arabino-2-hexulosonic acid ( 2-keto-D-gluconic acid ), Carbohydr. Res., 113 (1983) 163-165. 

Trimethyl-D-arabonolactone (XXVIII) has also been prepared from tetramethyl-D-fructofuranose (XXVI) by oxidation with nitric acid to give 3,4,6-trimethyl-2-keto-D-gluconic acid (XXVII), followed... 

Fig. 8.30 Microbial routes to 2-keto-L-gulonate (a) via L-sorbose (b) via 2,5-diketo-L-gulonate unwanted side reaction non-microbial steps are indicated by hatched arrows. Compounds 2,5DKG, 2,5-diketo-D-gluconate d-GcI, D-glucitol IDA, L-idonate 2KDG, 2-keto-D-gluconate L-Srb, L-sorbose L-Srn, L-sorbosone. Enzymatic activities ...

Another method of preparing keto aldonic acids, those of the 2-keto type, is by oxidation of the corresponding osone. Neuberg and Kitasato obtained 18 g. of calcium 2-keto-D-gluconate from 20 g. of the osone by the action of bromine at 20 . Similarly, 2-keto-n-galactonic and 2-keto-maltobionic acids were prepared by Kitasato. The substances were characterized generally as the brucine salts because of the amorphous nature of the calcium salts. 

The preparation of 2-keto-D-gluconic acid from D-glucosone was reported by Myrback. The osone was oxidized in alkaline solution... 

Erythorbic acid is synthesized by the reaction between methyl 2-keto-D-gluconate and sodium methoxide. It can also be synthesized from sucrose, and produced from Penicillium spp. 

The principal organic acids in grape are L(+)-tartaric, L(—)-malic, shikimic and citric acid. Gluconic, 2-keto-D-gluconic and mucic acids are present in rot grapes as metabolites of Botrytis Cinerea. The structures of these compounds are reported in Figure 1.2. 

By careful regulation of conditions, the ketose sugars D-fructose and L-sorbose can be transformed by the agency of nitric acid into the corresponding 2-keto-D-gluconic acid (XXII) and 2-keto-L-gulonic acid (XXVI), respectively. 

---