JP2000178294A - Method for producing pentaacetyl-β-D-glucose - Google Patents

Abstract

(57) [Problem] To provide an industrially safe and inexpensive method for producing pentaacetyl-β-D-glucose. SOLUTION: A novel pentaacetyl-β- reacting glucose with acetic anhydride in the presence of an aprotic solvent.
Provided is a method for producing D-glucose.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fragrance glycoside as a fragrance precursor, a gelling agent as an amphipathic solvent, a tocopherol glycoside, etc., which are incorporated in cosmetics, foods and drinks, and the like. Pentaacetyl-β useful as a synthetic intermediate for glycosides used in pharmaceutical and health products
-A method for producing D-glucose.

[0002]

2. Description of the Related Art An acetyl derivative of a saccharide is an important compound as an intermediate for synthesizing various saccharide derivatives such as alkyl glucosides. Among them, pentaacetyl-β-, which is a β-form among acetyl derivatives of glucose,
D-glucose can be used, for example, as an intermediate of the perfume glycoside as described above to obtain a β-D-glucoside of a perfume compound, and the β-form is α-form D-glucoside.
Since it is superior in hydrolyzability and microbial degradability to glucoside, it can easily release fragrance substances due to, for example, resident bacteria, and is industrially more practical and important. Therefore, in order to obtain a β-glycoside, it is more advantageous to use β-acetylated glucose as a raw material, and a method for producing the same has been proposed. For example, it is a production method by vigorous reaction at high temperature, in which glucose is added under reflux of acetic anhydride in the presence of an acidic catalyst and reacted [Methods, Carbohy].
dr. Chem. 2 , 211-215, (196
3)]. However, exhaustion of acetic acid vapor is unavoidable in this production method, and environmental measures such as deterioration of the working environment and installation of exhaust cleaning equipment are required, and if the reaction temperature is lowered, α-
The formation of the isomer increases, and the yield of the desired β-isomer decreases. On the other hand, a method for obtaining an acetyl derivative of a saccharide at a mild reaction temperature of 100 ° C. or lower using acetic acid as a reaction solvent (JP-A-10-237084), or using a lower alkyl ester of acetic acid such as ethyl acetate or butyl acetate as a solvent A method for producing a fully acetylated monosaccharide or oligosaccharide in which the reaction is carried out at a temperature of 80 to 120 ° C. (JP-A-62-42996) has been proposed. There is no description about α-form and β-form, and it is hard to say that it is a production method of β-form. In the latter, a large amount of acetic acid wastewater is generated, which is industrially problematic.

[0003]

As described above, there is a growing demand for pentaacetyl-β-D-glucose (hereinafter sometimes abbreviated as PAG) as an intermediate material for synthesizing various glycosides. From industrially safe and cheap P
There has been a demand for a production method capable of obtaining AG with high yield and high purity.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have considered safety and economic efficiency,
As a result of intensive research on a method capable of producing PAG with high purity and high yield, β-form acetylated glucose produced under severe conditions having problems in terms of hygiene and safety in the conventional production method is The present invention has been completed by finding a method for producing it industrially advantageously. That is, the present invention is a method for producing PAG with high purity and high yield by a mild reaction by reacting glucose with acetic anhydride in the presence of an aprotic solvent.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

The present invention is a method for obtaining pentaacetyl-β-D-glucose by adding glucose and acetic anhydride to an aprotic solvent and heating at 130 ° C. or lower.

[0007] The glucose used in the present invention may be of any purity, but is preferably anhydrous glucose. Also, the purity of acetic anhydride is not particularly limited as long as it is used for industrial purposes.

The aprotic solvent used in the present invention includes hydrocarbons, preferably aromatic hydrocarbons, more preferably toluene, xylene and trimethylbenzene. These aprotic solvents are not only excellent as reaction solvents capable of controlling the reaction temperature, but also can be used as an extraction solvent for the produced PAG and as a recrystallization solvent, which is why the present invention is industrially advantageous. It is.

In the reaction of the present invention, glucose is added to an aprotic solvent having a weight of 1 to 5 times, preferably 2 to 3 times the weight of glucose and, for example, sodium acetate as a reaction catalyst is added thereto, and the mixture is heated. The reaction is carried out while dropping 5 to 10 equivalents, preferably 6 to 8 equivalents of acetic anhydride in 1 to 5 hours. The reaction temperature is 80 to 130 ° C,
Preferably, the reaction is performed at a temperature of 100 to 115 ° C., and the reaction is continued for 5 to 10 hours after the completion of the dropwise addition.

The reaction catalyst used in the present invention includes:
For example, sodium acetate, pyridine, sulfuric acid, phosphoric acid and the like can be mentioned. Preferably, sodium acetate is used in an amount of 0.01 to 5 equivalents, preferably 0.05 to 2 equivalents, based on glucose. Good.

After completion of the reaction, the produced PAG is purified by crystallization and recrystallization to obtain a high-purity PAG.

[0012]

The embodiments of the present invention will be specifically described below with reference to examples.

EXAMPLE 1 20.6 kg of p-xylene, 10.3 kg (57.1 mol) of anhydrous glucose, and 0.3 kg of sodium acetate were added to a 100-liter reactor, and the mixture was stirred and heated.
When the temperature reaches ℃, 35 kg (343 mol) of acetic anhydride is gradually added dropwise over 2 hours. Reaction temperature of 105-110 ° C
The reaction is continued for about 6 hours after the completion of the dropwise addition while adjusting the pH.
After completion of the reaction, p-xylene and acetic acid are recovered by distillation under reduced pressure. Next, toluene is added to the collected residue and dissolved by heating. The toluene solution is washed with water at a temperature of 45 to 50 ° C., cooled, and recrystallized. After the toluene was separated by filtration, it was dried to obtain 19.2 kg of colorless crystals. From the analysis results of the obtained crystals, it was confirmed that the PAG was a single component of the β-form. Purity 99.7%, yield 86%.

Example 2 In the same manner as in Example 1 except that toluene was used instead of p-xylene used as the reaction solvent in Example 1,
18.5 kg of PAG were obtained. Purity 99.6%, yield 83
%.

[0015]

According to the present invention, pentaacetyl-β-D is industrially safe and inexpensive, and has high purity and high yield.
-Glucose can be produced.

Claims (2)

[Claims] 1. A process for producing pentaacetyl-β-D-glucose, which comprises reacting glucose with acetic anhydride in the presence of an aprotic solvent. 2. The method for producing pentaacetyl-β-D-glucose according to claim 1, wherein the aprotic solvent is an aromatic hydrocarbon.