Method for efficiently synthesizing carboxymethyl monosaccharide compound in one step and application of carboxymethyl monosaccharide compound

Abstract

The invention discloses a method for efficiently synthesizing a carboxymethyl monosaccharide compound in one step and application of the carboxymethyl monosaccharide compound, and the synthesis method comprises the following steps: (1) in a round-bottom flask, dissolving a basic catalyst in water, after the solution is cooled to room temperature, adding monosaccharide, fully stirring to dissolve the monosaccharide, and continuously stirring in a constant-temperature water bath; (2) dissolving a chloroacetic acid solid in water, slowly dropwise adding a chloroacetic acid solution into the round-bottom flask, and continuously reacting in a constant-temperature water bath; (3) monitoring the reaction process by adopting thin-layer chromatography, and adjusting the pH value of the solution by using acid after the reaction is finished; and (4) cooling to room temperature, carrying out solvent concentration and column chromatography separation, and collecting a target fraction. Monosaccharide and chloroacetic acid are used as raw materials, the monosaccharide compound is subjected to carboxymethylation modification under the alkaline catalysis condition, two carboxymethyl monosaccharide compounds with excellent moisture retention performance can be efficiently prepared in one step, and the preparation efficiency is remarkably improved; the synthesized compound is used as a humectant in tobacco products, and the physical moisture retention performance of the compound is superior to that of traditional propylene glycol.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a one-step and efficient method for synthesizing carboxymethyl monosaccharide compounds and application thereof. Background Art

[0002] Carbohydrate compounds are a class of compounds widely present in nature. They are not only an important source of energy in organisms, but also important information molecules in organisms. They have a wide range of pharmacological activities, such as regulating the body's immune function, anti-tumor, anti-diabetes, anti-oxidation, and anti-inflammatory. In daily life, they are widely used in many fields such as food, medicine, cosmetics, and health products. In addition, the addition of carbohydrates to cigarettes has a very important impact on the aroma quality of tobacco. Tobacco contains a wide variety of carbohydrates, which exist in various forms such as polysaccharides, glycosides, oligosaccharides, and complex polysaccharides. Among them, monosaccharide compounds such as fructose and galactose are the main components of water-soluble sugars in flue-cured tobacco, and their contribution to sensory comfort is very important. Reducing sugars such as fructose, galactose, and sucrose are sprayed into tobacco leaves before baking, which can become substrates for the Maillard reaction, improve the aroma quality of cigarettes, and increase the content of aroma substances. Secondly, reducing sugars such as fructose have good moisture absorption and moisture retention properties, and can be used as one of the important moisturizing ingredients in cigarettes. Carboxymethylation is one of the main methods to improve the solubility of carbohydrates such as polysaccharides. In addition, some oligosaccharides can significantly improve their moisture absorption and wettability after carboxymethylation. So far, the carboxymethylation reactions of monosaccharides such as fructose and galactose at home and abroad are generally multi-step reactions with harsh reaction conditions and complicated steps. Therefore, it is necessary to carry out research on the one-step synthesis of carboxymethylated monosaccharide compounds.

[0003] Based on this, this study used monosaccharides (fructose, galactose) and chloroacetic acid as raw materials, and modified the monosaccharide compounds by carboxymethylation under alkaline catalytic conditions to obtain two carboxymethyl monosaccharide compounds with excellent moisturizing properties. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for efficiently synthesizing carboxymethyl monosaccharide compounds in one step and its application. The method uses monosaccharides (fructose, galactose) and chloroacetic acid as raw materials, performs carboxymethyl modification on the monosaccharide compounds under alkaline catalytic conditions, and efficiently prepares two carboxymethyl monosaccharide compounds with excellent moisturizing properties in one step.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] A one-step method for efficiently synthesizing carboxymethyl monosaccharide compounds comprises the following steps:

[0007] (1) In a round-bottom flask, dissolve the alkaline catalyst in water. After the solution cools to room temperature, add the monosaccharide and stir thoroughly to dissolve it. Continue stirring in a constant temperature water bath;

[0008] (2) dissolving chloroacetic acid solid in water, slowly adding the chloroacetic acid solution dropwise to the round-bottom flask of step (1), and continuing the reaction in a constant temperature water bath;

[0009] (3) monitoring the reaction progress by thin layer chromatography, and adjusting the pH of the solution to 3.0-5.0 with acid after the reaction is completed;

[0010] (4) Cooling to room temperature, concentrating the solvent, separating by column chromatography, and collecting the target fraction, i.e., the carboxymethyl monosaccharide compound.

[0011] Preferably, in the above technical solution, in step (1), the alkaline catalyst is sodium hydroxide, potassium hydroxide or sodium carbonate, the molar ratio of the monosaccharide to the catalyst is 1:(1-1.3); and the monosaccharide is fructose and / or galactose.

[0012] Preferably, in the above technical solution, in step (1), the temperature of the constant temperature water bath is 60° C. and the stirring time is 1 hour; in step (2), the temperature of the constant temperature water bath is 60° C. and the reaction time is 3-4 hours.

[0013] Preferably, in the above technical solution, in step (2), the mass fraction of the chloroacetic acid solution is 20% to 50%, the molar ratio of monosaccharide to chloroacetic acid is 1:(1 to 1.2), and the reaction time is 2 to 5 hours.

[0014] Preferably, in the above technical solution, in step (3), the acid is sulfuric acid, glacial acetic acid or hydrochloric acid.

[0015] Preferably, in the above technical solution, the developing solvent of the thin layer chromatography in step (3) and the eluent of the column chromatography in step (4) are both a mixture of n-butanol, glacial acetic acid and water in a volume ratio of 4:1:(1-5).

[0016] A carboxymethyl monosaccharide compound is prepared by the above method.

[0017] Preferably, in the above technical solution, the carboxymethyl monosaccharide compound is 1-O-carboxymethyl-D-fructose and / or 6-O-carboxymethyl-D-galactopyranose.

[0018] The invention discloses an application of a carboxymethyl monosaccharide compound in improving the moisturizing property of tobacco products.

[0019] A humectant for tobacco products, comprising the above-mentioned carboxymethyl monosaccharide compound.

[0020] The above technical solution of the present invention has the following beneficial effects:

[0021] The present application provides a one-step efficient method for synthesizing carboxymethyl monosaccharide compounds, using monosaccharides (fructose, galactose) and chloroacetic acid as raw materials, and performing carboxymethyl modification on monosaccharide compounds under alkaline catalytic conditions, which can efficiently prepare two carboxymethyl monosaccharide compounds with excellent moisturizing properties in one step, significantly improving the preparation efficiency. The synthesized compounds can all be used as humectants in tobacco products, showing physical moisturizing properties superior to traditional propylene glycol, enhancing the moisturizing effect and sensory comfort of tobacco products, and have potential application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of 1-O-carboxymethyl-D-fructose.

[0023] Figure 2 This is the carbon NMR spectrum of 1-O-carboxymethyl-D-fructose.

[0024] Figure 3 This is the high-resolution mass spectrum of 1-O-carboxymethyl-D-fructose.

[0025] Figure 4 This is the infrared spectrum of 1-O-carboxymethyl-D-fructose.

[0026] Figure 5 This is the hydrogen nuclear magnetic resonance spectrum of 6-O-carboxymethyl-D-galactopyranose.

[0027] Figure 6 This is the carbon NMR spectrum of 6-O-carboxymethyl-D-galactopyranose.

[0028] Figure 7 This is the high-resolution mass spectrum of 6-O-carboxymethyl-D-galactopyranose.

[0029] Figure 8 This is the infrared spectrum of 6-O-carboxymethyl-D-galactopyranose. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0031] The main experimental reagents and instruments of this application are: fructose, galactose, chloroacetic acid, sodium hydroxide, potassium hydroxide, glacial acetic acid, hydrochloric acid, n-butanol, electronic balance, rotary evaporator, electromagnetic heating jacket, pH meter, Bruker Avance III 600 MHz nuclear magnetic resonance spectrometer (Bruker, USA), Thermo Nicolet Avatar 370 infrared spectrometer (Nicolet, USA), Exactive Orbitrap high-resolution mass spectrometer (Bruker, USA).

[0032] The technical method adopted by the present invention is as follows:

[0033] The two carboxymethyl monosaccharide compounds of the present application have the structural formula:

[0034]

[0035] 1-O-Carboxymethyl-D-fructose structure 6-O-Carboxymethyl-D-galactopyranose structure

[0036] The preparation method of the above two carboxymethyl monosaccharide compounds comprises the following steps:

[0037] Reaction formula of 1-O-carboxymethyl-D-fructose:

[0038]

[0039] The reaction formula of 6-O-carboxymethyl-D-galactopyranose:

[0040]

[0041] (1) In a round-bottom flask, dissolve the alkaline catalyst in water. After the solution cools to room temperature, add the monosaccharide and stir thoroughly to dissolve it. Continue stirring in a constant temperature water bath.

[0042] (2) Dissolve chloroacetic acid solid in water, slowly add chloroacetic acid solution dropwise into a round-bottom flask, and continue the reaction in a constant temperature water bath.

[0043] (3) The reaction progress is monitored by TLC, and the developing solvent is a mixed solvent of n-butanol, glacial acetic acid and water. After the reaction is completed, the pH of the solution is adjusted with acid. Finally, column chromatography is performed for separation, and the eluent is the same as the developing solvent, and the target fraction is collected.

[0044] Wherein, the alkaline catalyst in step (1) is one of sodium hydroxide, potassium hydroxide and sodium carbonate; and the molar ratio of monosaccharide to catalyst is 1:(1-1.3).

[0045] Wherein, the mass fraction of the chloroacetic acid solution in step (2) is 20% to 50%, the molar ratio of monosaccharide to chloroacetic acid is 1:(1 to 1.2), and the reaction time is 2 to 5 hours.

[0046] The acid in step (3) is one of sulfuric acid, acetic acid and hydrochloric acid. The developing agent is a volume ratio of n-butanol, acetic acid and water of 4:1:(1-5). After the reaction is completed, the pH of the solution is adjusted to 3.0-5.0 with an acid.

[0047] Conduct physical moisture retention performance test:

[0048] 1-O-carboxymethyl-D-fructose, 6-O-carboxymethyl-D-galactopyranose and propylene glycol were respectively prepared into aqueous solutions with a mass fraction of 10%. First, 500g of blank tobacco without flavoring or addition was placed at a temperature of (22±2)℃ and a relative humidity of (60±5)% for 48h. Then, 4 portions of tobacco were weighed in equal amounts, each of which was 100g, and 5.0g of the above aqueous solutions of the two carboxymethyl monosaccharides and propylene glycol were evenly applied to the 4 portions of tobacco, that is, the ratio of the above two carboxymethyl monosaccharide samples and propylene glycol added to the weight of the tobacco was 0.5%; at the same time, the blank sample was an equal amount of tobacco with 4.5g of water applied. Mix evenly under the same environmental conditions, weigh 6.0g of tobacco, and then place it in a glove box at (22±1)℃ and relative humidity (40±2)% to investigate its dehumidification process. The weight of tobacco is automatically tested once every 5 minutes using the electronic balance in the glove box, and the change of instant moisture content is analyzed to investigate its physical moisturizing effect. Each sample is tested in parallel three times. In addition, while weighing tobacco for physical moisturizing performance testing, the initial moisture content and dry weight of tobacco are determined using the traditional oven method. The data obtained from the experiment are calculated by formula to obtain the dry basis moisture content of tobacco at different times, and mathematical analysis software is used to perform nonlinear fitting on the dry basis moisture content over time data to obtain the fitting equation formula between moisture content and time. The starting and ending points of tobacco moisture content within a certain range are determined, and the dehumidification time required for tobacco from the starting point to the ending point is investigated based on the time difference between the two points, thereby obtaining the investigation results of the physical moisturizing properties of two carboxymethyl monosaccharide compounds.

[0049] The following is a detailed description with reference to the embodiments:

[0050] Example 1

[0051] In a 100 mL round-bottom flask, add sodium hydroxide solution (100 mmol, mass fraction 8%) and fructose 18 g (100 mmol) and stir thoroughly to dissolve them. After stirring in a constant temperature water bath at 60 ° C for 1 h, slowly add chloroacetic acid solution (100 mmol, mass fraction 30%) dropwise, and continue the reaction in a constant temperature water bath at 60 ° C for 3 h (TLC detection).

[0052] After the reaction was completed, the pH of the solution was adjusted to 5.0 with glacial acetic acid.

[0053] The mixture was cooled to room temperature, the solvent was concentrated, and column chromatography was used for separation. The eluent was n-butanol: glacial acetic acid: water (4:1:1). The target fractions were collected and concentrated under reduced pressure to obtain 16.37 g of 1-O-carboxymethyl-D-fructose with a yield of 68.8%.

[0054] Example 2

[0055] In a 100 mL round-bottom flask, add potassium hydroxide solution (120 mmol, mass fraction 10%) and galactose 18 g (100 mmol) and stir thoroughly to dissolve them. After stirring in a constant temperature water bath at 60 ° C for 1 hour, slowly add chloroacetic acid solution (110 mmol, mass fraction 35%) dropwise, and continue the reaction in a constant temperature water bath at 60 ° C for 4 hours (TLC detection).

[0056] After the reaction was completed, the pH of the solution was adjusted to 4.0 with hydrochloric acid solution.

[0057] The mixture was cooled to room temperature, the solvent was concentrated, and the mixture was separated by column chromatography. The eluent was n-butanol: glacial acetic acid: water (4:1:3). The target fractions were collected and concentrated under reduced pressure to obtain 19.12 g of 6-O-carboxymethyl-D-galactopyranose with a yield of 80.3%.

[0058] Example 3

[0059] In a 100 mL round-bottom flask, potassium hydroxide solution (120 mmol, mass fraction 10%) and mixed monosaccharides (fructose 9 g, galactose 9 g) were added and stirred thoroughly to dissolve. After stirring in a constant temperature water bath at 60 ° C for 1 h, chloroacetic acid solution (110 mmol, mass fraction 35%) was slowly added dropwise, and the reaction was continued in a constant temperature water bath at 60 ° C for 3 h (TLC detection).

[0060] After the reaction was completed, the pH of the solution was adjusted to 5.0 with hydrochloric acid solution.

[0061] The mixture was cooled to room temperature, the solvent was concentrated, and the mixture was separated by column chromatography. The eluent was n-butanol: glacial acetic acid: water (4:1:5). The target fractions were collected and concentrated under reduced pressure to obtain 7.22 g of 1-O-carboxymethyl-D-fructose with a yield of 60.7% and 7.98 g of 6-O-carboxymethyl-D-pyranose with a yield of 67.1%.

[0062] Structural characterization data of the compound:

[0063] 1-O-Carboxymethyl-D-fructose: 1 H NMR (600MHz, D 2O), δ: 4.22~4.14(m,3H),4.08~3.93(m,1H),3.91~3.86(m,2H),3.78~3.75(m,1H),3.73~3.61(m,3H),3.58~3.50(m,2H),3.49~3.48(m,1H). 13 C NMR (150MHz, D 2 O):β-configuration:174.78,101.07,80.94,76.31,73.22,69.70,68.55,63.67;α-configuration:174.39,97.97,76.36,74.52,72.49,69.39,68.12,62.58.HRMS[MH] - :m / z calcd for C 8 H 13 O 8 237.1827,found237.1843.IR(KBr),v / cm -1 :3396.62,2934.98,1731.92,1239.92,1128.12,1071.47,800.98,701.20.

[0064] 6-O-Carboxymethyl-D-galactopyranose: 1 H NMR (600MHz, D 2 O), δ: 4.38 (d, J = 1.2Hz, 1H), 4.05 ~ 4.03 (m, 3H), 3.79 ~ 3.64 (m, 3H), 3.61 ~ 3.53 (m, 4H), 3.47 ~ 3.43 (dd, J = 15.0Hz, J = 4.8Hz, 1H), 3.30 ~ 2.28 (m, 1H). 13 C NMR (150MHz, D 2 O),δ:β-configuration:174.15,96.22,73.24,72.46,71.59,70.59,68.78,67.72;α-configuration:174.11,92.13,70.71,69.32,68.83,68.57,68.09,67.56.HRMS m / z:calcd for C 8 H 13 O 8 [MH] - 237.1827,found 237.1837.IR(KBr),v / cm -1:3392.00,2929.43,1735.70,1239.64,1130.91,1097.43,1069.56,800.93,702.21.

[0065] Physical moisturizing performance test:

[0066] The physical moisturizing performance test and evaluation method was adopted, with Golden Leaf brand cigarette reference cigarette tobacco as the carrier, and propylene glycol and blank tobacco as control samples, to carry out the physical moisturizing performance test of 1-O-carboxymethyl-D-fructose and 6-O-carboxymethyl-D-pyranose in tobacco.

[0067] (1) Test method

[0068] 500 g of evenly mixed tobacco was placed in an environment with a temperature of (22±1)°C and a relative humidity of (60±2)% for 48 hours, and then divided into two groups (about 100 g in each group). One group was sprayed with humectant evenly in a certain proportion, and the other group was sprayed with an equal amount of distilled water as a control. In the test process of moisture change in tobacco dehumidification or moisture absorption process, the above two tobacco samples are placed in a constant temperature and humidity chamber with a temperature of (22±1)°C and a relative humidity of (A±2)% for 48 hours, and then 4 samples with a sampling volume of about 6g (accuracy of 0.0001) are taken out using a 70×40mm weighing bottle. Two of them are tested for moisture content using the national standard oven method, and the error is not more than 0.1%. The average value is the initial moisture content of this group of samples. The other two are placed in a sulfuric acid dryer with a relative humidity of (B±2)% (when B﹥A, it is a moisture absorption process; when B﹤A, it is a dehumidification process), and the sulfuric acid dryer is covered and placed in a constant temperature and humidity chamber with a temperature of (22±1)°C for heat preservation to carry out moisture absorption or dehumidification experiments to investigate the moisture content change of tobacco during dehumidification or moisture absorption.

[0069] The tobacco samples were balanced at a temperature of 22°C and a humidity of 60% for 48 hours; the weighing bottles used were numbered and weighed to an accuracy of 0.1 mg. The samples were weighed with weighing bottles, and the sample weight was about 5g, accurate to 0.1 mg; the balance measurement software was opened to calibrate the balance; the weighing bottle containing the sample was placed on the balance, and after placement, the balance measurement software was started to continuously weigh the sample weight; the sample weight was measured once every minute, and the collection time was 72 hours. After the test reaches the specified time, the test is stopped; the test sample is taken out and its moisture content is tested according to the method of "YC / T 31-1996 Tobacco and Tobacco Products-Determination of Moisture Content", and the instantaneous moisture content at each time point is calculated using the difference method. The obtained data was analyzed and processed using mathematical software to obtain the fitted logarithmic equation x=-t 1 ×ln[(y-y0) / A 1] and the corresponding fitting curve, and calculate the time of the starting point and the ending point in a certain moisture content range, and then examine the dehumidification time required for the tobacco from the starting point to the ending point based on the time difference between the two points. The longer the dehumidification time, the better its physical moisturizing performance, thus examining the physical moisturizing performance of the humectant. The moisture content of the tobacco in the test process is calculated by the following formula 1-1.

[0070]

[0071] Mi: tobacco weight at time i / g;

[0072] M 0 : Dry basis weight of tobacco after spraying humectant / g;

[0073] Xi: moisture content of cut tobacco on dry basis at time i (%).

[0074] (2) Operation method

[0075] 1-O-carboxymethyl-D-fructose, 6-O-carboxymethyl-D-galactopyranose and propylene glycol were respectively prepared into aqueous solutions with a mass fraction of 10%. First, 500g of blank tobacco without flavoring or addition was placed at a temperature of (22±2)℃ and a relative humidity of (60±5)% for 48h. Then, 4 portions of tobacco were weighed in equal amounts, each of which was 100g. 5.0g of the above aqueous solutions of the two carboxymethyl monosaccharides and propylene glycol were evenly applied to the 4 portions of tobacco, that is, the ratio of the above two carboxymethyl monosaccharide samples and propylene glycol added to the weight of the tobacco was 0.5%; at the same time, the blank sample was an equal amount of tobacco with 4.5g of water applied. Mix evenly under the same environmental conditions, weigh 6.0g of tobacco, and then place it in a glove box at (22±1)℃ and a relative humidity of (40±2)% to observe its dehumidification process. The electronic balance in the glove box automatically tests the weight of the cut tobacco every 5 minutes, and analyzes the change in the instant moisture content to examine its physical moisture retention effect. Three parallel tests are conducted on each sample. In addition, while weighing the cut tobacco for the physical moisture retention performance test, the initial moisture content and dry weight of the cut tobacco are determined using the traditional oven method.

[0076] (3) Data fitting

[0077] The experimental data were used to calculate the dry basis moisture content of tobacco at different times using formula 1-1, and mathematical analysis software was used to perform nonlinear fitting on the dry basis moisture content variation over time to obtain the equation x = -t 1 ×ln[(yy 0 ) / A 1 ] 0 , A 1 and t 1 , the results are shown in Table 1.

[0078] Table 1 Fitting equation constant y 0 , A 1 ,t 1 The calculation results

[0079]

[0080] (4) Results and analysis

[0081] The moisture content of the cut tobacco was determined to be 14% as the starting point and 10% as the ending point, and the change of the moisture content of the cut tobacco within this range was investigated. 1 ×ln[(yy 0 ) / A 1 ], calculate the time of the starting point and the ending point respectively, and then examine the dehumidification time required for the two sample tobacco from the starting point to the ending point according to the time difference between the two points, so as to investigate the physical moisturizing properties of the two carboxymethyl monosaccharide compounds and propylene glycol. The test results are shown in Table 2.

[0082] Table 2 Dehumidification time required for tobacco from dry basis moisture content of 14% to 10%

[0083]

[0084] From the results in Table 2, it can be seen that when the moisture content of tobacco cuts on a dry basis decreases from 14% to 10%, the dehumidification time of the blank tobacco cuts is 439 minutes, the dehumidification time of the tobacco cuts added with two carboxymethyl monosaccharide compounds exceeds 800 minutes, and the dehumidification time of the tobacco cuts added with propylene glycol is only 667 minutes, among which the dehumidification time of 6-O-carboxymethyl-D-pyranose is 351 minutes longer than that of propylene glycol, and the moisturizing performance is more significant. This shows that the physical moisturizing performance of the two carboxymethyl monosaccharides is significantly better than that of the traditional moisturizer propylene glycol, and has potential application value.

[0085] Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various choices and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is limited by the claims and their equivalents.

Claims

1. A one-step efficient method for synthesizing carboxymethyl monosaccharide compounds, characterized in that: The following steps are involved: (1) In a round-bottom flask, dissolve the alkaline catalyst in water. After the solution cools to room temperature, add the monosaccharide and stir thoroughly to dissolve it. Continue stirring in a constant temperature water bath; (2) dissolving chloroacetic acid solid in water, slowly adding the chloroacetic acid solution dropwise to the round-bottom flask of step (1), and continuing the reaction in a constant temperature water bath; (3) monitoring the reaction progress by thin layer chromatography, and adjusting the pH of the solution to 3.0-5.0 with acid after the reaction is completed; (4) Cooling to room temperature, concentrating the solvent, separating by column chromatography, and collecting the target fractions.

2. The one-step efficient method for synthesizing carboxymethyl monosaccharide compounds according to claim 1, characterized in that: In step (1), the alkaline catalyst is sodium hydroxide, potassium hydroxide or sodium carbonate, the molar ratio of the monosaccharide to the catalyst is 1:(1-1.3); the monosaccharide is fructose and / or galactose.

3. The one-step efficient method for synthesizing carboxymethyl monosaccharide compounds according to claim 1, characterized in that: In step (1), the temperature of the constant temperature water bath is 60° C. and the stirring time is 1 h; in step (2), the temperature of the constant temperature water bath is 60° C. and the reaction time is 3-4 h.

4. The one-step efficient method for synthesizing carboxymethyl monosaccharide compounds according to claim 1, characterized in that: In step (2), the mass fraction of the chloroacetic acid solution is 20% to 50%, the molar ratio of monosaccharide to chloroacetic acid is 1:(1 to 1.2), and the reaction time is 2 to 5 hours.

5. The one-step efficient method for synthesizing carboxymethyl monosaccharide compounds according to claim 1, characterized in that: In step (3), the acid is sulfuric acid, glacial acetic acid or hydrochloric acid.

6. The one-step efficient method for synthesizing carboxymethyl monosaccharide compounds according to claim 1, characterized in that: The developing solvent of the thin layer chromatography in step (3) and the eluent of the column chromatography in step (4) are both a mixture of n-butanol, glacial acetic acid and water in a volume ratio of 4:1:(1-5).

7. A carboxymethyl monosaccharide compound, characterized in that: The carboxymethyl monosaccharide compound is prepared by the method according to any one of claims 1-6.

8. The carboxymethyl monosaccharide compound according to claim 7, characterized in that: The carboxymethyl monosaccharide compound is 1-O-carboxymethyl-D-fructose and / or 6-O-carboxymethyl-D-galactopyranose.

9. Use of the carboxymethyl monosaccharide compound according to any one of claims 7-8 in improving the moisturizing properties of tobacco products.

10. A humectant for tobacco products, characterized in that: The humectant comprises the carboxymethyl monosaccharide compound according to any one of claims 7-8.

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