526-98-7

Basic information

• Product Name: L-xylo-hex-2-ulosonic acid
• Synonyms: L-Xylohexulosonic acid;2-Keto-L-gulonsure;2-Oxo-2-deoxy-L-gulonic acid;2-Oxo-L-gulonic acid;L-xylo-2-Hexulosonic acid;3-Keto-L-gulonic acid;Einecs 208-403-5;Idonic acid, 2-keto-, L-
• CAS NO: 526-98-7
• Molecular Formula: C₆H₁₀O₇
• Molecular Weight: 194.1394
• EINECS: 208-403-5
• Mol File: 526-98-7.mol
• Article Data: 12

Chemical Properties

• Melting Point: 171 °C
• Boiling Point: 550.6 °C at 760 mmHg
• Flash Point: 300.9 °C
• Appearance: /
• Density: 1.757g/cm³
• Vapor Pressure: 2.04E-14mmHg at 25°C
• Refractive Index: 1.593
• PKA: 2.10±0.54(Predicted)
• Water Solubility: 335.3g/L at 20℃
• CAS DataBase Reference: L-xylo-hex-2-ulosonic acid(CAS DataBase Reference)
• NIST Chemistry Reference: L-xylo-hex-2-ulosonic acid(526-98-7)
• EPA Substance Registry System: L-xylo-hex-2-ulosonic acid(526-98-7)

Safety Data

• Hazardous Substances Data: 526-98-7(Hazardous Substances Data)

Usage

Purification Methods

Crystallise 2-keto-L-gulonic acid from half its weight of water, wash it with Me2CO and dry it in vacuo. [Reichstein et al. Helv Chim Acta 17 311 1934, NMR: Crawford et al. J Am Chem Soc 102 2220 1980. Beilstein 3 IV 1985.]

InChI:InChI=1/C6H10O7/c7-1-2(8)3(9)4(10)5(11)6(12)13/h2-4,7-10H,1H2,(H,12,13)/t2-,3+,4-/m0/s1

Synthetic route

methanol (67-56-1) + L-sorbose (87-79-6) + copper diacetate (142-71-2) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Behandeln einer wss.Loesung des von Kupfer-Ionen befreiten Reaktionsprodukts mit Brom;

L-sorbose (87-79-6) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With oxygen; Pt/Al2O3 at 50℃; under 750.06 Torr; for 2.86667h; other catalysts; var. reaction time;	39 % Chromat.
With hexamethylenetetramine; oxygen; platinum on activated charcoal In water at 50℃; under 750.06 Torr; Product distribution; Kinetics; var. of pH, base, catalyst;
With pyridine; oxygen; Pt/Al2O3 In water at 50℃; under 750.06 Torr; Rate constant; var. tertiary amines or tetraalkylammonium hydroxide, var. supports of Pt catalyst;

L-sorbosone (49865-02-3) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With water; bromine im diffusen Licht;

O2,O3;O4,O6-dicyclohexylidene-α-L-xylo-[2]hexulofuranosonic acid (52507-87-6) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With water
With water

sodium gluconate (6027-87-8) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With sodium chlorate; vanadia

D-sorbitol (50-70-4) → L-idonic acid (1114-17-6) + 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Gluconobacter melanogenus IFO 3293 mutant; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

D-sorbitol (50-70-4) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Gluconobacter melanogenus IFO 3293 mutant; Yield given;
Multi-step reaction with 3 steps 1: 31 percent 2: 46 percent / NaI, Ca(OH)2 / H2O / 1 h / 20 °C / anode - platinum, cathode - stainless steel 3: 0.1N aq. HCl / 1 h / 90 °C View Scheme

L-sorbose (87-79-6) → L-idonic acid (1114-17-6) + 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Gluconobacter melanogenus IFO 3293 mutant; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

3,5,4,6-diethylidene-L-xylo-2-hexulosonic acid (136090-58-9) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With hydrogenchloride at 90℃; for 1h;

2,5-diketo-D-gluconic acid (2595-33-7) → fructonic acid (669-90-9) + 2-keto-L-gulonic acid (526-98-7) + D-lyxo-hex-5-ulosonic acid (13425-76-8) + 5-keto-D-gluconic acid (5287-64-9)

Conditions	Yield
With Ru-TPPTS; sulfuric acid; hydrogen; sodium iodide In water at 27℃; under 7500.6 Torr; for 8h; Product distribution; other pH, temperature, reaction time, hydrogen pressure, catalyst amount;

L-sorbose (87-79-6) + nitric acid (7697-37-2) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield

L-sorbose (87-79-6) + sulfuric acid (7664-93-9) + dihydrogen peroxide (7722-84-1) + iron(II) sulfate → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield

calcium salt of/the/ L-gulonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With chromium(VI) oxide; iron(III) sulfate; water

calcium salt of/the/ L-idonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With chromium(VI) oxide; iron(III) sulfate; water
durch aerobe Oxidation mit Hilfe von Enzym-Praeparaten aus Pseudomonas fluorescens;

calcium salt of/the/ D-gluconic acid + calcium salt of/the/ L-idonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
durch aerobe Oxidation mit Hilfe eines Enzym-Praeparats aus Pseudomonas fluorescens;
durch aerobe Oxidation mit Hilfe von Enzym-Praeparaten aus Pseudomonas chromo-spirans;

tetrachloromethane (56-23-5) + L-sorbose (87-79-6) + dinitrogen tetraoxide (10544-72-6) + calcium sulfate → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Behandeln der Calcium-Salze der erhaltenen Saeuren mit Oxalsaeure in Wasser;

O2,O3;O4,O6-diisopropylidene-α-L-xylo-<2>hexulofuranosonic acid-hydrate → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With water

L-sorbose (87-79-6) + aqueous sodium hydrogencarbonate + air + platinum/charcoal → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
at 25℃; Schuetteln (16-72 h);

L-sorbose (87-79-6) + water (7732-18-5) + oxygen + platinum/charcoal → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
at 4 - 80℃; pH (3.6-8.4);

L-sorbose (87-79-6) + nitric acid (7697-37-2) + sodium nitrite → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield

sodium-salt of/the/ L-gulonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With water; sodium acetate; acetic acid und Vanadium(V)-oxid und Natriumchlorat;

sodium-salt of/the/ L-idonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With water; acetic acid; sodium bromide und Chrom(VI)-oxid bei der anodischen Oxidation;
With sodium chlorate; phosphoric acid; water anschl. mit Methanol und Vandium(V)-oxid;

L-sorbose (87-79-6) + aqueous NaOH-solution + oxygen + platinum/charcoal → L-threonic acid (7306-96-9) + 2-keto-L-gulonic acid (526-98-7) + oxalic acid (144-62-7)

Conditions	Yield

L-sorbopyranose (7270-77-1) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
With oxygen; sodium carbonate; hyper-cross-linked polystyrene-Pt-THF at 70℃; for 3.66667h; pH=5.9; Product distribution; Further Variations:; Temperatures; pH-values;

calcium-salt of/the/ L-idonic acid → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
durch aerobe Oxidation mit Hilfe von Enzym-Praeparaten aus Pseudomonas-Arten sowie aus Acetobacter aerogenes;

1,3:2,4-di-O-ethylidene-D-sorbitol (50895-31-3) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Multi-step reaction with 2 steps 1: 46 percent / NaI, Ca(OH)2 / H2O / 1 h / 20 °C / anode - platinum, cathode - stainless steel 2: 0.1N aq. HCl / 1 h / 90 °C View Scheme

L-xylo-[2]hexosulose bis-phenylhydrazone (5934-57-6) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Multi-step reaction with 2 steps 1: benzaldehyde; water; ethanol / Reagens: Essigsaeure 2: water; bromine / im diffusen Licht View Scheme

O2,O3;O4,O6-dicyclohexylidene-α-L-sorbofuranose (20880-90-4) → 2-keto-L-gulonic acid (526-98-7)

Conditions	Yield
Multi-step reaction with 2 steps 1: pyridine; potassium hydroxide; potassium permanganate 2: water View Scheme

Reaxys ID: 11364755 → 2-keto-L-gulonic acid (526-98-7) + ascorbic acid (50-81-7)

Conditions	Yield
In Tri-n-octylamine; 8-methyl-1-nonanol; tri(n-decyl)amine; water at 30℃; Purification / work up;

diazomethane (186581-53-3, 908094-01-9) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid methyl ester (3031-98-9)

Conditions	Yield
With methanol; diethyl ether at -10℃;

Diazoethan (1117-96-0) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid ethyl ester (5965-56-0)

Conditions	Yield
With ethanol

methanol (67-56-1) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid methyl ester (3031-98-9)

Conditions	Yield
With hydrogenchloride; trimethyl orthoformate
With hydrogenchloride; dimethylsulfite
With acidic cationen-exchanger
sulfuric acid at 65 - 66℃; under 760.051 Torr; for 2 - 2.5h;	90 - 97 %Chromat.

propan-1-ol (71-23-8) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid propyl ester (109848-63-7)

Conditions	Yield
With acidic cationen-exchanger

ethanol (64-17-5) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid ethyl ester (5965-56-0)

Conditions	Yield
With acidic cationen-exchanger

i-Amyl alcohol (123-51-3) + 2-keto-L-gulonic acid (526-98-7) → L-xylo-[2]hexulosonic acid isopentyl ester (110462-68-5)

Conditions	Yield
With acidic cationen-exchanger

2-keto-L-gulonic acid (526-98-7) + 2-methyl-propan-1-ol (78-83-1) → L-xylo-[2]hexulosonic acid isobutyl ester (113535-34-5)

Conditions	Yield
With acidic cationen-exchanger

2-keto-L-gulonic acid (526-98-7) → ascorbic acid (50-81-7)

Conditions	Yield
With hydrogenchloride; water; butan-1-ol
With water at 100℃;
With hydrogenchloride; water

2-keto-L-gulonic acid (526-98-7) + isopropyl alcohol (67-63-0) → L-xylo-[2]hexulosonic acid isopropyl ester (88669-03-8)

Conditions	Yield
With acidic cationen-exchanger

2-keto-L-gulonic acid (526-98-7) + benzyl alcohol (100-51-6) → L-xylo-[2]hexulosonic acid benzyl ester (98056-03-2)

Conditions	Yield
With cationen-exchanger at 130℃;

2-keto-L-gulonic acid (526-98-7) + butan-1-ol (71-36-3) → L-xylo-[2]hexulosonic acid butyl ester (98055-99-3)

Conditions	Yield
With acidic cationen-exchanger

Upstream product

• 52507-87-6 O²,O³;O⁴,O⁶-dicyclohexylidene-α-L-xylo-[2]hexulofuranosonic acid 
• 87-79-6 L-sorbose 
• 2595-33-7 2,5-diketo-D-gluconic acid 
• 20880-90-4 O²,O³;O⁴,O⁶-dicyclohexylidene-α-L-sorbofuranose 
• 5934-57-6 L-xylo-[2]hexosulose bis-phenylhydrazone 
• 50895-31-3 1,3:2,4-di-O-ethylidene-D-sorbitol 
• 7270-77-1 L-sorbopyranose 
• 7697-37-2 nitric acid 
• 7732-18-5 water 
• 56-23-5 tetrachloromethane 
• 10544-72-6 dinitrogen tetraoxide 
• 7664-93-9 sulfuric acid 
• 7722-84-1 dihydrogen peroxide 
• 136090-58-9 3,5,4,6-diethylidene-L-xylo-2-hexulosonic acid 

Downstream Products

• 50-81-7 ascorbic acid 
• 98056-03-2 L-xylo-[2]hexulosonic acid benzyl ester 

Relevant articles and documents

AuPt Alloy on TiO2: A Selective and Durable Catalyst for l-Sorbose Oxidation to 2-Keto-Gulonic Acid

Pt nanoparticles were prepared by a sol immobilization route, deposited on supports with different acid/base properties (MgO, activated carbon, TiO2, Al2O3, H-Mordenite), and tested in the selective oxidation of sorbose to 2-keto-gulonic acid (2-KGUA), an important precursor for vitamin C. In general, as the basicity of the support increased, a higher catalytic activity occurred. However, in most cases, a strong deactivation was observed. The best selectivity to 2-KGUA was observed with acidic supports (TiO2 and H-Mordenite) that were able to minimize the formation of C1/C2 products. We also demonstrated that, by alloying Pt to Au, it is possible to enhance significantly the selectivity of Pt-based catalysts. Moreover, the AuPt catalyst, unlike monometallic Pt, showed good stability in recycling because of the prevention of metal leaching during the reaction.

METHOD FOR EXTRACTING 2-KETONE-L-GULONIC ACID FROM A POLAR, PREFERABLY AQUEOUS SOLVENT

The invention relates to a method for extracting 2-ketone-L-gulonic acids from a polar, preferably aqueous solvent, preferably from a solvent which contains a mixture of ascorbic acid and 2-ketone-L-gulonic acid, by means of liquid-liquid extraction with the aid of an extraction agent which contains a tertiary amine and a polar organic diluent. Preferably, the inventive method also comprises steps for retro-extracting the 2-ketone-L-gulonic acid and for returning the extraction agent. The invention also relates to a method for producing ascorbic acid from 2-ketone-L-gulonic acid and for isolating the thus produced ascorbic acid.

Platinum-containing hyper-cross-linked polystyrene as a modifier-free selective catalyst for L-sorbose oxidation

Impregnation of hyper-cross-linked polystyrene (HPS) with tetrahydrofuran (THF) or methanol (ML) solutions containing platinic acid results in the formation of Pt(II) complexes within the nanocavities of HPS. Subsequent reduction of the complexes by Hsub