CS234864B1 - Process for the preparation of L-glyceraldehyde and L-erythritis - Google Patents

Abstract

The invention relates to a method of preparing L-glyceraldehyde and L-erythrose. The essence of the invention consists in the fact that L-arabinose is oxidized with bromide acetate in an environment of 80 to 90 percent acetic acid at temperatures of 15 to 20 QC and for a period of 15 to 20 minutes. The reaction mixture after concentration at a pressure of 2 to 5 kPa on a rotary evaporator is dissolved in ethyl acetate and extracted with water. The resulting formyl esters of sugars are released using 5 to 10 percent acetic acid and the free sugars are selectively separated using a strong acid cation exchanger in a calcium buffer with a 40 to 60% aqueous solution of ethyl alcohol as an eluent. L-glyceraldehyde and L-erythrose are isolated, which are purified by adding activated carbon and dried. The invention has applications in the chemical, biochemical and medical industries.

Description

The invention relates to a process for the preparation of L-glyceraldehyde and L-erythrose.

L-glyceraldehyde and L-erythrose are not found naturally in nature. The best known method of preparation is so-called. Wohl Carbohydrate Degradation [A. Wohi, F. Momber: Ber. 47,3346 (1914); A. Wohl, F. Momber: Ber. 50, 476 (1917)]. By multi-step synthesis from L-arabinose via the L-manonic acid lactone intermediates, L. mannitol, prepared

1,2-5,6-diisopropylidene of L-mannitol, which oxidized with lead acetate and liberated L-glyceraldehyde [E. Baer: Helv. Chim. Acta: 17, 622 (1934). Perlin, A. S., Brice prepared from L-sorbose by oxidation with lead acetate 3-O-formyl-2-O-glycolyl-L-glyceraldehyde, which, after hydrolysis, yielded L-glyceraldehyde, A.S. Perlin, C. Brice: Can. J. Chem. 34.85 (1956)]. L-erythrose was first produced by degradation of L-arabinose [A. Wohl: Ber. 32, 3666 (1899)]. I.N. Baxter, A.S. Perlin prepared L-erythrose from 2,3-O-isopropylidene-L-mannose, which was reduced with sodium borohydride to 2,3-O-isopropylidene- / 3-L-ramnitol, oxidized with sodium periodate and the resulting

2,3-O-isopropylidene-L-erythrose, provided hydrolysis to yield L-erythrose [J. N. Baxter, A.S. Perlin: Can. J. Chem. 38, 2217 (1960)]. It was also prepared from 6-deoxy-2,3-O-isopropylidene-L-mannose, which, after reducing periodate oxidation and liberating the isopropylidene groups, gave L-erythrose [A. S. Perlin, Methods in Carb. Chem. Vol. 67). Said methods for the preparation of L-glyceraldehyde and L-erythrose by degradation processes are not demanding but the end products did not achieve the desired purity. Synthetic preparation of Lglyceraldehyde as well as L-erythrosis gives the products of the desired purity, but the synthesis consists of several difficult stages and the basic raw material is scarce, difficult to access, making the preparation expensive.

The disadvantage ipodstatnej scale removing process for the preparation of L-glyceraldehyde and L-erythrose according to the invention, which is characterized in that the aqueous solution of L-arabinose is oxidized by Neta lead tetraacetate in a 80 to 90% of acetic acid] at a temperature of 15 to 20 ^Q C for 15 to 20 minutes. The reaction mixture is concentrated to a syrup, dissolved in ethyl acetate and extracted with water. Sugar ester forms are released using 10-20% acetic acid. The mixture of L-glyceraldehyde and L-erythrose sugars is selectively resolved using a strong acid cation exchanger in calcium form. A 40-60% aqueous ethanol solution was used as eluent. The pure fractions of L-glyceraldehyde and L-erythrose are concentrated to a syrup on a rotary evaporator at a pressure of 2 to 5 kPa and dried.

The advantage of the proposed method of preparing L-glyceraldehyde and L-erythrose compared to previous method of preparation is that the present method of preparation is ^one simpler and more effective, as allows to work in a simpler devices that are commercially available and both sugars L-glyceraldehyde and L-erythrose are produced in one stage of high purity.

Example 1

L-arabinose (13 g) was dissolved with stirring in 80% acetic acid (1000 ml) and lead (75 g) was added portionwise over 15 min. The oxidation was carried out at 20 ° C. The reaction mixture was concentrated at a pressure of 2 kPa to rotačneij evaporator at 30 ^D C to a syrup, treated with ethyl acetate (414 ml) and extracted with prídavkoím 10 ° C water twice ('27, 5 ml). The extract in ethyl acetate was dried over anhydrous sodium sulfate (100 g), filtered and concentrated to a syrup (5 g) on a rotary evaporator. The resulting formyl esters were hydrolyzed with 10% acetic acid (215 µL) at 80 ° C for 3 hours. The acetic acid was removed by rotary evaporation at 30 ° C and the resulting syrup was dried in a desiccator over phosphorus pentoxide (3.9 g). The reaction mixture of sugars (1.5 gj) is dissolved in a 40% aqueous solution of ethyl alcohol (2 ml) and applied to a column packed with a strongly acid cation exchanger (Dowex 50 WX 8, 0.07-0.13 mm grain size) in calcium form with a length 100 centimeters and 2.5 cm in diameter using a 40% aqueous ethanol solution as eluent, and using a fraction collector at a flow rate of 25 ml / h ^-1 , the individual fractions are monitored by ascending paper chromatography (Whatman Nol chromatography paper) in an acetate system. ethyl acetate, acetic acid, 4% boric acid in water in a 9: 1: 1 by volume ratio and detected spectrophotometrically with silver alkaline nitrate or with 3.5 dinitrosylicylic acid.

Fraction 1 to 25 negative for sugars, fraction 26 to 34 formyl esters (0.26 g), fraction 35 to 36 negative for sugars, fraction 37 to 50 L-glyceraldehyde (1.65 g), fraction 51 to 65 negative for sugars fractions 66-73 L-arabinose (0.24 g), fractions 74-76 sugar-negative and fractions 77-126 L-erythrose (0.39 g). The fractions containing L-glyceraldehyde and L-erythrosis were concentrated at 2 kPa on a rotary evaporator to syrup at 30 ° C, purified by addition of active carbon (0.2 g), filtered and dried. L-glyceraldehyde was obtained in a yield of 64.0%, optical rotation (a) -16 ° ^z0 _D, L-erythrose was obtained in a yield of 15.7%, optical rotation ( ') ²⁰ _D + 35 °.

Example 2

Dissolve L-arabinose in water (18 mL) and 90% acetic acid (850 mL) at 15 ° C. The solution was vigorously stirred and lead acetate (44.3 g) was added portionwise over 20 minutes while cooling to 15 ° C. After standing for 20 minutes at ^Q C e, oxalic acid (8.1 g oxalic acid solution) was added to the reaction mixture. in 100 ml acetic acid) and the resulting precipitate is filtered, the oxidation of the formaldehyde mixture is extracted with ethyl acetate (2 x 200 µl), ethyl acetate-insoluble L-arabinose (12 g) can be used as starting material without further purification Ethyl acetate is extracted with 90% water (2 x 25 ml) where the L-arabinose residues are dissolved in water and dried over anhydrous sodium sulfate, distilling off ethyl acetate at 35 ° C gives a colorless syrup which is hydrolyzed with 20% acetic acid at temperature 80 ° C for 3 hours (225 ml of a 20% acetic acid in water solution) After hydrolysis, acetic acid is removed by distillation at 5 kPa on a rotary evaporator at a temperature of 35 ° C to syrup (4.1 gj.

The separation was carried out according to Example 1. A 60% aqueous ethanol solution was used as eluent.

L-glyceraldehyde was obtained in 61% yield, optical rotation (also _D ²⁰ -15.5 °, L-erythrose was obtained in 17.1% yield, optical rotation (qid ²⁰ + 34 ^{° C)} .

The invention has extensive application in the chemical, biochemical and medical industries.

Claims (1)

Process for preparing L-glyceraldehyde and L-erythrose, characterized in that L-arabinose is oxidized with lead acetate in a medium of 80 to 90% acetic acid at 15 to 20 ° C for 15 to 20 minutes, the reaction mixture is concentrated to a syrup, Dissolve in ethyl acetate and extract with water, formyl ester The sugars are liberated with 5-10% acetic acid and the free sugars are selectively separated using a strong acid cation exchanger, isolated in calcium form with 40-60% aqueous ethanol as eluent and dried.