CS260394B1 - A method of preparing aldoses - Google Patents

Abstract

The purpose of the aldose preparation method is to improve the aldose preparation method, i.e. to simplify and economize these preparation methods. The stated purpose is achieved by adding citric acid to N-phenylglycosylamine, formaldehyde, ethanol, water and a molybdate compound in a molar ratio of molybdenum in oxidation state VI to citric acid of 1: at least 2 and allowing it to react at a temperature of up to 100°C. The method of preparing aldoses is used in organic chemistry.

Description

260394

The invention relates to a process for the preparation of aldoses. In some methods of isolating one of the aldose precipitates, the reaction of aldoses with anilines has been used, employing a different crystallization ability of the resulting N-phenylglycosylamines. N-Phenylribozylamine isolates N-phenyllyxozylamine from the precipitation of arabinose and ribose and from N-phenyllyxozylamine [x]. Bílik, J. Capiovic: Chem. Rev. 27, 547 (1973)], from a mixture of fructose, glucose and mannose, N-phenylmanozylamine [V. Bílik, K. Tihlárik: Chem. L. Petrus: Chem. Annals 30, 359 (1976)] and from a mixture of Larabinose and D-xylose N- (4-nitro-phenyl) -L-arbinozylamine [V. Bílik, A. Kramář: Chem. Rumors 33, 641 (1979)]. From N-phenylglycosylamines, aldose can be released by formaldehyde [T. Fujita, T. Sato: Bull.Chem. Soc. Japn 33, 353 (1960)], benzaldehyde [R. L. Whistler, J.N. BeMiller: Me-thods Carbohydr. Chem. 1, 81 (1962)], by hydrolysis by the hydrofoam technique [V. Bílik, J. Čaplovič: Chem. Rumors 27: 547 (1973); V. Bílik, L. Petruš: Chem.Zvěsti 30, 359 (1976)] by hydrolysis with a strong acid ion exchanger (CS AO No. 196 996).

In all of these reactions, the polybenzene ions in the release procedures are not required. Therefore, the aldose solutions had to be deionized prior to the corresponding derivatization of the corresponding N-phenylglycosylamines, thereby increasing the labor and cost of the prepared aldoses. Aldoses are epimerized in weakly acidic aqueous solutions in the presence of molybdenum ions to form a uniform mixture of C-2-epimeric aldoses [U.S. Pat. sheets 77, 496 (1983)].

The above drawbacks are substantially obviated by the method of preparation of aldoses according to the invention, wherein citric acid is added to the N-phenylglycoslamine, formaldehyde, ethanol, water and molybdenum compound in the molybdenum molar ratio in the oxidation stage VI. to citric acid 1: at least 2 and reacting to a temperature of up to 100 ° C. The advantage of the proposed method of preparation is that it is not necessary to remove molybdenum ions, most often by anion exchangers, with subsequent concentration of the solutions, thereby saving wages, materials, energy and substantially saving the use of some equipment (evaporators, columns). Example 1

A mixture of 25.5 g (0.1 mol) of N-phenyl-D-mannosylamine, 0.25 g (2.10-4 mol) of hexaammonium heptamolybdate tetrahydrate, 0.59 g (2.8, 10 ~ 3 mol) citric acid monohydrate (molar ratio of citric acid to molybdenum in the V1 oxidation step is 2: 1), 15.8 ml (0.2 mol) of 35% w / w aqueous formaldehyde solution, 35 ml of 96% ethanol and 190 ml of water heating for 3 h at 90 DEG C. The inhibition of D-mannose epimerization is determined by paper chromatography (Whatman No 1) using the elution system A: acetone, 1-butanol and 5: 1: 4 by volume. with an elution system flow rate of 18 to 20 h, followed by detection with aniline hydrophthalate The chromatographic pattern shows the presence of D-mannose and the presence of D-glucose in the trace amount. 1.31 and in elution system B: 1.30 Example 2

The procedure is as in Example 1, except that the mixture is heated at 100 ° C for 2 h. Chromatographic recording shows the presence of D-mannose and the presence of D-glucose in the stopmomass. Example 3

Proceeding as in Example 1, except that a mixture of 22.5 g (0.1 mol) of N-phenyl-D-ribozylamine, 25 mg (2.10 -5 mol) of hexammonium heptamolybdate tetrahydrate is used, 59 mg (2.8.times.10@-4 mol) of citric acid monohydrate (molar ratio of citric acid to molybdenum in oxidation stage VI is 2: 1), 15.8 ml (0.2 mol) of 35 wt. % aqueous formaldehyde solution, 35 ml 96 wt. ethanol and 190 ml of water. Chromatography shows the presence of D-ribose and the presence of D-arabinose in trace amounts. Mobility related to D-glucose 1.00 is for D-ribose a system of A: 2.13 and in elution system B: 1.90 and for D-arabinose in elution system A: 1.41 and in elution system B: 1.30. Attaches

The procedure is as in Example 3, except that N-phenyl-L-lyxozylamine is used. Chromatographic recording shows the presence of L-lyxose and the presence of L-xylose in trace amounts. The mobility of sana D-glucose for L-lyxosis in the elution system A: 1.82 and in the elution system B: 1.66a for L-xylose in elution system A: 1.72 and elution system B: 1.54 . In the Examples, epimerization inhibition temperatures of 90 and 100 ° C are reported, but epimerization is inhibited at even lower temperatures, for example, when concentrating aldose solutions. Citric acid forms a stable complex with molybdenum ions, which inhibits both epimerization and substantial longer periods of time as described in the Examples. However, it is not effective to store aldose solutions for longer periods at lower temperatures, as aldose spills are

Claims (1)

260394 good breeding ground for some microorganisms that can spoil them. The process for preparing aldoses can find widespread use in organic chemistry for both D- and L-series. SUBJECT A process for the preparation of aldoses from the corresponding N-phenylglycosylamines by the action of formaldehyde, characterized in that N-phenylglycosylamine, formaldehyde, ethanol, water amolybdene compound is added to the citric acid in the molar ratio of molybdenum liv. at least 2 and reacted at a temperature of up to 100 ° C.