CS233220B1 - Process for preparing D-mannose - Google Patents

Abstract

The invention relates to a method for the preparation of D-mannose. The essence of the invention is that a mixture of D-glucose and D-mannose is selectively separated using a strong acid cation exchanger in calcium form, a 50 to 60% aqueous solution of ethyl alcohol is used as an eluent. The pure fraction, which contains D-raanose, is concentrated and crystallized from ethyl alcohol after concentration and decolorization with activated charcoal. The invention has extensive use in the stage of biochemical processes, in medicine and in the food industry.

Description

The present invention relates to a process for preparing D-mannose from a mixture of sugars D-mannose, D-glucose.

D-mannose is one of the very rare aldohexose carbohydrates, which is most commonly found in nature in the form of mannan and glucomanene polysaccharides. These sources can be prepared by acid or enzymatic hydrolysis; like the seeds of Phytelephas macrocarpa [ti. Riess: Ber. 22, 609 (1889) J from Porthyra umbilicalis algae C. S. Hudson,

E.L. Jackson: J. Am. Chem. Soc. 56, 958 (1944) 7, or from yeast cell walls

Saccacharomyces cerevisiae fj. Sandula, A. Vojtkova: Folia Microbiol. 19, 94 (1974).

*

It can also be prepared by oxidation of mannitol [e. Fischer, J. Hirschberger, Ber. 21,

1805 (1889) 7. Bilik describes the preparation of D-mannose by epimerizing D-glucose with molybdenum ions as a catalyst, wherein D-mannose isolates phenylhydrazone as a derivative [A. O. 149051J · J. Kubala et al. Have prepared crystalline D-mannose through the N-phenyl-D-manozylamine derivative [(A.O. 214431) J.

The above methods for the preparation of D-mannose from glucomannens, oxidation of D-mannitol, or isolation from a mixture of D-glucose and D-mannose by derivatives are difficult because of the low content of D-mannose and the yields are low in both natural materials and cell walls. . The multi-stage synthesis of mannitol oxidation is of theoretical importance. Isolation of D-mannose by means of an insoluble derivative with phenylhydrazine and resp. Aniline is complicated by the fact that these substances are poisons.

The above-mentioned disadvantages are substantially eliminated by the process for the preparation of D-mannose according to the invention, which is characterized in that the mixture of D-glucose, D-mannose is selectively separated by means of a strong acid cation exchanger in calcium form. The eluent was an aqueous ethanol solution. The D-mannose fraction is concentrated under reduced pressure to a syrup and crystallized from ethyl alcohol.

The advantage of the proposed method of preparing D-mannose over the prior art methods is that the method of preparation is more vigorous and healthy, allowing it to operate in simple, non-energy intensive and commercially available equipment. It allows to work without environmental pollutants such as phenylhydrazine, which is a carcinogenic antibody and aniline as a particularly dangerous poison, and their scale-down requires special equipment and is expensive. The resulting D-glucose by-product can be unchanged in the unchanged state into the original reaction or after commercial crystallization.

Example 1

The salivary acid cation exchanger (Dowex 50 WX 8 0.07 to 0.13 mm) is packed into a column of 100 cm length and 2.5 cm in diameter, successively passed through (1000 ml) with 10% hydrochloric acid and left to act for 24 hours. The ion exchanger is then washed with distilled water (5,000 ml) until neutral pH 7 · Activation is carried out (2,000 ml) with 20% calcium chloride solution and the excess ions are washed out with distilled water to a negative reaction to the chloride. Dissolve 2 g of a mixture containing 50% D-mannose in 4 ml (50% ethyl alcohol) and apply to a column packed with a saliva acid cation exchanger (Dowex 50 WX 8 0,07 to 0,13 mm in calcium form) with a length of 100 cm and a diameter of 100 cm 2.5 cm.

50% ethyl alcohol was used as eluent using a fraction collector at a flow rate of 10 ml / h. The individual fractions were monitored by paper chromatography (Whatman No 1), followed by 8: 2: 1 ethyl acetate-pyridine-water gradient chromatography and detected with alkaline silver nitrate or with 3.5 dinitrosalicylic acid spectrophotometrically. Fractions 1 to 25 were negative for sugars, fractions 26 to 33 contained D-glucose, fractions 34 to 36 were negative for sugars, and fractions 37 to 45 contained D-mannose.

The fraction containing D-mannose was concentrated in vacuo to a syrup, purified by the addition of activated carbon (0.1 g), filtered and lyophilized. Addition of 96% ethyl alcohol (5 mL) crystallized (0.80 g) of D-mannose. By repeated crystallization of the mother liquors, another (0.10 g) of D-mannose was obtained to obtain a yield of 90%. Specific rotation ()) ² ® + 14 ° (C = 5 water), Melting point 130-132 ° C.

Example 2 g of a mixture containing 75% D-glucose and 25% D-mannose are dissolved in (4 ml) 60% ethyl alcohol and applied to a column packed with a strongly acidic cation exchanger (Dowex 50 WX 8 0.07 to 13.13 mm in calcium). form) with a length of 100 cm and a diameter of 2.5 cm. 60% ethyl alcohol was used as eluent using a fraction collector at a flow rate of 10 ml / h. The individual fractions were monitored by papeir chromatography (Whatman No 1), followed by 8: 2: 1 ethyl acetate-pyridine-water, and detected with silver alkaline nitric acid or 3.5 dinitrosalicylic acid spectrophotometry. Fractions 1 to 22 were negative for sugars, fractions 23 to 40 contained D-glucose, fractions 41 to 43 were negative for sugars, and fractions 44 to 50 contained D-mannose. The fraction containing D-mannose was concentrated in vacuo to a syrup, purified by addition of activated carbon (01 g), filtered and lyophilized (0.245 g). Addition of 96% ethyl alcohol (5 ml) crystallizes (0.23 g) D-mannose. By repeated crystallization of the mother liquors, an additional (0.01 g) of D-mannose is obtained, yielding up to 96% recovery. Specific rotation () * ° +, 4 ° (C = 5 water), Melting point 130-132 ° C.

The invention has extensive application in the study of biochemical accidents, in medicine and in the food industry.

Claims (1)

OBJECT OF THE INVENTION Process for the preparation of D-mannose from a mixture of D-glucose and D-mannose, characterized in that D-mannose is isolated by means of a strong acidic cation exchanger in calcium form with 50 to 60% ethyl alcohol as an eluting agent, which after purification with activated charcoal and concentration crystallizes from ethyl alcohol.