SU792876A1 - Method of preparing tetronic acid - Google Patents

Description

sodium salt of a-carboxytartic acid when heated in the presence of an equimolar amount of mineral acid, the sodium salt of tetronic acid is isolated by the addition of dimethylformamide to the reaction mass, followed by fractional distillation of the solution, which is then in a mixture of anhydrous methanol and diethyl ether is treated with a solution of dry hydrogen chloride in diethyl ether at a temperature of minus 40 - minus 50 ° C, followed by separation, the resulting tetronic acid.

In this method, it is necessary to strictly observe the indicated molar ratios of the disodium salt and acid. The presence of even a slight excess of inorganic acid leads to contamination of the target product with the salt of anhydrous acid.

If necessary, the preparation of tetroic acid can be purified by non-recrystallization from dioxane.

The yield of crude and recrystallized tetronic acid is 90 and 72%, respectively.

Example 1. a-Carbethoxetronate acid. To the suspension of sodium malonic ether, obtained from 51.8 g (2.25 g-at) sodium and 460 ml (2.85 mol) of malonic ether, in 1.5 liters of dry diethyl ether, solid carbon dioxide is added with stirring until a uniform mixture. The introduction of solid carbon dioxide maintains the temperature of the mixture in the range of -30 to -40 ° C and, with stirring, a solution of 85.3 ml (1.125 mol) of chloroacetyl chloride in 85 ml of dry diethyl ether is added to -40 ° C. Then, excluding the access of moisture, they are moved for 4 hours, allowing the contents of the flask to warm to room temperature, and left overnight. The precipitate was filtered, not dried, dissolved in 800 ml of 3N hydrochloric acid, and the solution was immediately shaken with three 100 ml portions of diethyl. the ether. From the aqueous solution when standing in the refrigerator, the following are isolated. Metallic a- | KarbetOXY-tetronic acid, which is filtered off and washed on the filter with cold water. Yield 100 g (52%). T. pl. 125-127 ° C (lit. 124-125 ° C).

Found,%: C 49.05; H 4.68 CrHgOg.

Calculated,%: C 48.04; H 4.68.

D.Innat, R: Ieva So.l a- {ka1r: boioitet | rO) H10 acid. 138 g (0.8-1 mol) a-Ik; alpibetoxyetronate acid is dissolved in 500 ml of ethanol when heated. Separately, 80 g (2.0 mol) of sodium hydroxide are dissolved in 500 ml of water. The solutions are poured together and boiled for 2 hours in a water bath. It is cooled, filtered, the crystals on the filter are washed with ethyl alcohol and dried at 80 C. The yield is 148 g (98%).

In order to obtain an analytical sample, it is crystallized from a mixture of water - debris (1: 1).

Found,%: C 31.42; H 1.09. CgHaOaNas. Calculated,%: C, 31.94; H 1.07.

Sodium salt of tetronic acid. 132 g (0.7 mol) of the disodium salt of cc-carboxytronic acid is dissolved by heating in 500 ml of water and cooled to

10 ° C. To the solution with stirring, pour a mixture of conc. hydrochloric acid (containing 0.7 mol of HC1) and 100 g of ice. Then this mixture is carefully poured into a flask heated in a boiling water bath,

and move 10 min. The resulting solution was evaporated in a water jet pump vacuum (20 mm Hg) in boiling Noybahn water to a volume of 250 ml, then 400 ml of dimethylformamide was added and evaporated through a reflux condenser under the same conditions to a volume of 300 ml. The precipitate is filtered off and 100 ml of dimethylformamide is filtered onto the filter. The combined filtrate was evaporated to dryness in vacuo. The resulting product is 100 ° C. The colorless or slightly yellowish sodium salt of tetronic acid is obtained. Yield 79 g (94%).

To obtain an analytical sample, it is recrystallized from a mixture of ethanol and diethyl ether (1: 1). The chemically pure sodium salt of tetronic acid is isolated. Yield 5.1 g (70%).

Found,%: C 39.50; H 2.39. C4H3O3Na, Calculated,%: C 39.36; H 2.47.

Tetronic acid. A mixture of 90 ml of methanol and 60 ml of a saturated ethereal solution of dry hydrogen chloride, cooled to -50 ° C, is added to 36.6 g (0.3 mol) of the tetronic acid sodium salt, which has been thoroughly ground in a mortar. The mixture is vigorously moved for 1.5 hours, excluding the access of moisture and cooling with a bath of acetone and solid carbon dioxide, the temperature of which is maintained in the range from -40 to

-50 ° C. Then 150 ml of dry ether are added. Quickly, immersing in warm water, heat the contents of the flask to + 20 ° C and move for 5 minutes. Filtered, the filter cake washed with a mixture of 10 ml

methanol and 10 ml of dry ether. The filtrate is evaporated in a water jet vacuum pump to dryness and the residue is kept in a vacuum desiccator over KOH.

The yield of tetronic acid 27 g (90%).

-. The analytical sample is obtained by repeated recrystallization from dioxane, i.e. 140 ° C (decomp. (L; it. 141 ° C with decomp.) Found:%: C 47.94; H 4.15.

C4H40z.

Calculated,%: C, 47.94; H 4.03.

Claims (4)

1.L. Wolf, Lieb. Ann., 1896, 291, p. 231. 2.E. Vepagu Veg 1907, 40, p. 1080 3. USSR author's certificate NO 104298, C 07 D 307/32. 4.Т.Р.С. Mullholland, R. Foster, D.V. Haydock J.Chem. Soc. (Perkin Trans I), 1972 c. 1225 (prototype).