CS232647B1 - Preparation method of d-arabinose by means of oxidative degradation of d-calcium gluconate - Google Patents

Abstract

The present invention relates to a process for preparing D-arabinose from calcium D-glucomate. Essence of the invention is that calcium D-gluconate is degraded to D-arabinose by two equivalents of hydrogen peroxide in water calcium acetate solution 0 to 0.3 mol. 11 in the presence of catalytic amounts of copper ions at temperature 20 to 30 ° C for 5 to 7 hours. The invention has utility in the chemical industry and biochemistry.

Description

The invention relates to the preparation of D-arabinose by oxidative degradation of calcium D-gluconate.

Methods for the preparation of D-arabinose are mainly based on shortening the carbon chain of D-gluconic acid, respectively D-glucose, respectively. suitable derivatives of these compounds. The most commonly used for this purpose are Ruff's degradation and D-glucose dithioacetal degradation, less frequently Wohn's degradation, Werman's degradation and Hunsdicker reaction [J. Stanek, M. Cerny, J. Kocourek, J. Pacak: Monosaccharides, Nakl. ČSAV, Praha 1960, p. 88]. Alkaline decomposition of the peroxy compounds prepared by Koenigs-Knorr reaction of tert-butyl peroxide with chromoacetyl D-glucose, respectively, is also utilized. acetyl chloride per-O-acetyl-D-gluconic acid [M. Schulz, P. Berlin: Angew ,. Chem. 79, 940 (1967)] and for the preparation of D-5 (U- ¹⁴ C jarabinose by oxidative degradation of 4-nitrophenylhydrazone D- (U- ¹⁴ C) -glucose [V. Bilik, P. Biely, M. Matulova: Chem. 33, 782 (1979)] The practical application of the preparation of D-arabinose in larger amounts is based on the oxidative degradation of the sodium salt of D-gluconic acid with hypochlorous acid [RL Whistler, JN BeMiller: Methods in Carbohydrate Chemistry, Academic Press, New York - London 1962 71] and oxidative degradation of the calcium salt of D-gluconic acid with an equivalent amount of hydrogen peroxide under the catalytic action of ferric ions [HC Fletcher, HW Diehl, CS Hudson: J. Amer. Chem. Soc., 72, 4546 (1950)].

SUMMARY OF THE INVENTION Calcium D-gluconate is degraded to D-arabinose by two equivalents of hydrogen peroxide in an aqueous solution of calcium acetate having a concentration of 0 to 0.3 mol. 1 ^_1 in the presence of catalytic amounts of copper ions at a temperature of 20-30 ° C for 5-7 hours.

An advantage of the proposed process for the preparation of D-arabinose is that the conversion of calcium D-gluconate to D-arabinose over ferric ion catalyzed oxidative degradation is up to 0 1/3. The elaborated procedure is very simple, it does not require any technological equipment and all necessary chemicals are commercially available.

Example 1

Calcium D-gluconate (220 g), calcium acetate (60 g), copper sulphate (3 g) are dissolved in water (2000 ml) and then gradually added to the solution at 20 to 30 ° C (over 1 to 2 hours). hours) 30% hydrogen peroxide 647 ka (220 mL). The reaction mixture was allowed to stand at room temperature for 5 hours and finally 1 mol of sulfuric acid (800 mL) was added. I ^-1 and allow to stand for at least 2 hours. The precipitated calcium sulfate is filtered off, the filtrate is concentrated and the distillation residue is boiled with methanol (1000 ml). The methanol solution is filtered, appropriately concentrated (to 1/3 volume) and allowed to crystallize at room temperature for 24 to 48 hours to give a first crystalline fraction of D-arabinose (48 g, ie 32%). The mother liquor is deionized by addition of a cation exchange ion exchanger (400 ml strong acid cation exchanger - Ostion KS 0210) and after removal by addition of an anion exchanger (400 ml strong basic anion exchanger - Ostion AT 0209). The washings were concentrated and the distillation residue was crystallized from methanol (200 mL) to give a second crystalline portion of D-arabinose (28 g, ie 18%). The mother liquor is concentrated and chromatographed on a 2.5 x 120 cm Dowex 50 W, X-8 ion exchange column, 75-150 μτη in a Ca-cycle, eluting with water at a flow rate of 30 ml / h to give a third crop of D-arabinose (33 g, ie 22% in an elution volume of 500 to 900 ml).

Example 2

The procedure is as described in Example 1 except that copper acetate is used instead of copper sulfate. For further processing after removal of the calcium sulfate, the filtrate is deionized by the addition of an ion exchange resin and then an anion exchange resin. The washings were concentrated and the distillation residue was crystallized from methanol (300 mL) to give a first crop of crystalline D-arabinose (86 g, i.e. 57 percent). The mother liquor was concentrated and chromatographed on a Dowex 50 W ion exchange column as described in Example 1 to give a second crop of D-arabinose (21 g, i.e. 14%).

Chromatographically pure (SD-arabinose (obtained by dissolving A g of D-arabinose in A ml of water and A ml of methanol) has a melting point of 159-160 ° C and [ _.alpha. ] _D @ ²³ -153 ± 2 [deg.] ° ± 1 ° (c 2, water) Literature [J.

Stanek et al. Monosaccharides, Nakl. ČSAV, Praha 1960, p. 79] for β, D-arabinose gives tt 158-159 ° C and [α] _D -175 ° -> -105 ° (water).

The invention has utility for the preparation of D-arabinose, which is used in large quantities for the preparation of D-ribose, and further for the preparation of riboflavin. At the same time, D-arabinose is used as a starting compound for a number of other syntheses and also for the study of carbohydrate biochemical transformations.

Claims (1)

Process for the preparation of D-arabinose by oxidative degradation of calcium D-gluconate, characterized in that the calcium D-gluconate is degraded by two equivalents of hydrogen peroxide in an aqueous solution of calcium acetate having an inventive concentration of 0 to 0.3 mol. ¹¹ in the presence of catalytic amounts of copper ions at 20-30 ° C for 5-7 hours.