CS260398B1 - A method of preparing aldoses - Google Patents

Abstract

The purpose of the method for preparing aldoses is to improve the methods for preparing aldoses, i.e. to simplify and economize these methods of preparation. The stated purpose is achieved by adding oxalic acid to N-phenylglycosylamine, water and/or ethanol and a molybdate compound in a molar ratio of molybdenum with oxidation state VI to oxalic acid of 1: at least 4 and the reaction mixture is hydrolyzed by steam stripping. The method for preparing aldoses has applications in organic chemistry and biochemistry.

Description

The invention relates to a process for the preparation of aldoses.

In some methods of isolating one aldose from a mixture of aldoses, the reaction of aldoses with anilines has been utilized which exploits the different crystallization capacity of the resulting N-phenylglycosylamines. N-phenylribozylamine is isolated from arabinose-ribose mixture, and N-phenyllyxozylamine from V. a mixture of xylose and lyxose [V. Bilili, J. Caplovic: Chem. Rumors 27, 547 (1973)], fructose, glucose, and mannose N-phenylmanozylamine [V. Bílik, K. Tihlárik: Chem. Rumors 28, 106 (1984)], from D-glycero-L-glucoheptose and D-glycero-L-manoheptose N-phenyl-D-glycero-L-manoheptozylamine [V. Bilik, L. Petrus: Chem. Rumors 30, 359 (1976)] and from a mixture of L-arabinose and D-xylose N- (4-nitrophenyl) -L-arabinozylamine [V. Bílik, A. Kramář:

Chem. Rumors 33, 641 (1979)].

Aldoses can be released from formaldehyde from N-phenylglycosylamines [T. Fujita, T. Sato: Bull. Chem. Soc. Japan 33, 353 (1960) J, benzaldehyde [R. I ,. Whistler, J. N. BeMiller: Methods Carbohydr. Chem. 1, 81 (1962)], by hydrolysis by the water vapor bleeding technique [V. Bílik, J. ČápltíviČ: Chětti. Rev. 27, 547 (1973); V. Bílek, L. Petruš: Chem. Rumors 30, 359 (1976)], by strong acid ion exchange hydrolysis (CS AO No. 196 996).

In all these reactions, molybdate ions need not be present in the release procedures. Therefore, aldose solutions had to be deionized prior to appropriate derivatization to the corresponding N-phenylglycosylamines, which increases laboriousness and increases the cost of the prepared aldoses. The aldoses are epimerized in weakly acidic aqueous solutions in the presence of molybdenum ions to form an equilibrium mixture of C-2-epimeric aldoses [V. Bilik: Chem. 77, 496 (1983)].

The above-mentioned disadvantages are substantially eliminated by the process for the preparation of aldoses according to the invention, which comprises adding oxalic acid in a molar ratio of molybdenum having an oxidation degree of VI to oxalic acid of 1: at least 4 to N-phenylglycosylamine, water and / or ethanol and a molybdenum compound. and the reaction mixture is hydrolyzed by a steam-jet technique.

Example 1

To a solution containing 25 ml of water, 2 ml of 99 wt. acetic acid, 3 g of hexaammonium heptamolybdate tetrahydrate are added 250 g of D-glucose monohydrate. The mixture is heated after reaching 90 ° C for 50 min. The reaction mixture was diluted with 120 mL of methanol, then 120 mL of 96 wt. ethanol and the solution was allowed to crystallize at 23 ° C for 2 days. The crystalline D-glucose is filtered off (105 g, i.e. 42% yield based on the starting D-glucose). The filtrate is treated with 1: 1 methanol / ethanol to 500 mL total volume, 100 mL of aniline is added and allowed to stand at 23 ° C for 20 h.

Crystalline N-phenyl-D-manozylamine is filtered off (80 g, i.e. 25% yield of D-mannose based on the starting D-glucose and 43% yield, respectively, based on recovered D-glucose) and washed with a mixture of methanol and ethanol. in the ratio of 1: 1 by weight. The obtained N-phenyl-D-manozylamine contains 4 mg of molybdenum in oxidation stage VI. To 500 ml of water is added 80 g of N-phenyl-D-manozylamine, 21 mg of oxalic acid dihydrate (molar ratio of oxalic acid to molybdenum in oxidation stage VI is 4: 1) and the mixture is hydrolyzed by water vapor bleeding until a charge is obtained. Distilled 800 ml of a mixture of water and aniline. The solution containing D-mannose is treated with charcoal, the filtrate is concentrated and the distillation residue is crystallized from 150 ml of methanol to give 46 g (i.e. 80% yield, starting from N-phenyl-D-mannoslamine) of D-mannose. The mother liquor was concentrated, and the residue was dissolved in 30 ml of methanol to give a second crystalline fraction of D-mannose (7 g, i.e. 12.5% yield).

Example 2

A mixture of 100 g of L-arabinose, 1 g of molybdic acid and 500 ml of water is heated at 95 ° C for 3 h. The solution is concentrated, the syrup residue is dissolved in 200 ml of methanol and left to crystallize at 23 ° C for 24 h. The crystalline L-arabinose (60 g) is filtered off, the mother liquor is concentrated, and the residue is dissolved in 40 ml of a 96% w / w mixture. ethanol: water (7: 1, w / w) added 15 ml of aniline. The mixture was allowed to stand at 23 ° C for 24 h. Crystalline N-phenyl-L-ribozylamine (32 g, i.e. 21.5% yield of L-ribose in the N-phenyl-L-ribozylamine form relative to the starting L-arabinose and L-ribozylamine, respectively).

53.5% yield by recovery of recovered L-arabinose) was filtered off.

The obtained N-phenyl-L-ribozylamine contains

1.5 mg of molybdenum in oxidation stage VI. To 250 ml of water, 32 g of N-phenyl-L-ribozylamine, 8 mg of oxalic acid dihydrate (molar ratio of oxalic acid to molybdenum in oxidation stage VI is 4: 1) are added, and the mixture is hydrolyzed by steam-jetting until 350 ml of a mixture of water and aniline is distilled into the receiver. The solution containing D-ribose is treated with charcoal and the filtrate is concentrated to dryness to give 20 g of chromatographic pure L-ribose. Crystalline L-ribose is obtained by crystallization from 100 wt. ethanol.

The epimerization is also inhaled at substantially lower temperatures than in the above-mentioned method of hydrolysis by the steam-jet technique, for example when the aldose solutions are concentrated. Oxalic acid forms a stable complex with molybdate ions, which inhibits the epimerization of aldoses even for a substantial period of time, as exemplified in the examples. It is not more efficient to store aldose solutions for extended periods of time at lower temperatures, since aldose solutions are good

B nutrient bases for some microorganisms that can destroy them.

The method for the preparation of aldoses can be widely used in organic chemistry in the preparation of aldoses of both the D- and L-series.

Claims (1)

SUBJECT Process for the preparation of aldoses from the corresponding N-phenylglycosylamines, characterized in that oxalic acid is added to the N-phenylglycosylamine, water and / or ethanol and molybdenum compound in a molar ratio INVENTION molybdenum having an oxidation degree of VI to oxalic acid of 1: at least 4 and the reaction mixture is hydrolyzed by a water vapor flash technique.