SU408943A1 - METHOD OF OBTAINING L-WINE ACID - Google Patents

Description

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This invention relates to a method for obtaining optically active L-tartaric acid, which can be used in pharmaceutical chemistry, preparative organic chemistry for separating racemates into optical antipodes in theoretical studies.

There is a known method of obtaining b-tartaric acid by splitting grape acid into optical antipodes using an optically active base. Grape acid is treated in water with 2- (0-gluco-13-huloheptohexahydroxyl) -benzimidazole, followed by precipitation of the salt by the addition of alcohol. The precipitated salt is separated, washed with alcohol, decomposed with ammonium hydroxide, the base is filtered off and the lead salt of L-tartaric acid is precipitated from the filtrate by the action of lead acetate. The removed salt is filtered off, washed, decomposed with hydrogen sulfide and the solution obtained is evaporated until the crystals of L-vinyl acid precipitate.

Characteristic features of the lime method are the necessity of working with spiatic salts and hydrogen sulfide, a large number of stages for the isolation of L-vinpoic acid, and the need to pre-synthesize the optically active base used.

In order to simplify the process, L (- | -) - Tpeo-l (/ g-nitrofeiyl) -2-amino-1,3-iropanediol is used as an optically active base, the resulting mixture of diastereomers is boiled with methyl alcohol, the remaining 5 L-tartaric acid salts are filtered, dried, dissolved in water, the aqueous solution is passed through a cation exchange resin, for example KU-1, to obtain an aqueous solution of L- and DL-tartaric acids and subsequent separation of these acids by fractional crystallization. The optically active base used in the proposed method is a waste from the production of chloramphenicol and, therefore, is quite accessible.

5 P r im. 30g L {-f -) - tpeo-l- {l-nitrophenyl) 2-amino-1, 3-propanediol is dissolved in 270 ml of boiling methyl alcohol and 26.5 g of grape acid is added to the solution. The reaction mass of the cues is t for 1 hour,

0 is cooled to 20 ° C and stirred at this temperature for another I hour. The precipitate is filtered off and washed twice with 25 ml of methyl alcohol. The dried crystals are boiled with 500 ml of methyl alcohol at 5 hours PID, 1.5 hours, the solution is cooled to 20 ° C and mixed at this temperature for another 1.5 hours. The crystals are filtered, washed with methanol, dried, dissolved in water and the aqueous solution is passed through a column with KU-1.

0 The obtained filtrate is evaporated in a water bath until the crystals of DL-tartaric acid precipitate, the mixture is kept at room temperature for 12 hours, the precipitated crystals are filtered off, the filtrate is evaporated in a desiccator over concentrated sulfuric acid to precipitate L-tartaric crystals. After recrystallization from water, the yield of L-tartaric acid is 25%, so pl. 167-169 ° C, 1068 (20%; H2O). The subject of the invention. A method for producing L-tartaric acid by splitting of grapeic acid into optical antipodes using an optically active base, characterized in that, in order to influence the process, b () - threo-1 - ("- nitrophenyl) -2-amino-1,3propanediol, the resulting mixture of diastereomers is boiled with methyl alcohol, the remaining precipitate of L-tartaric acid salt is filtered, dried, dissolved in water, the aqueous solution is passed through a cation-exchange resin the floor HAND aqueous solution of L- and DL-tartaric acid and subsequent separation of L- and DL-tartaric acid by fractional crystallization.