A 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester and its applications

Abstract

This invention relates to a 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester and its applications. Using 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one as a raw material, a esterification reaction is used to prepare the 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester. This compound exhibits good storage stability and flavoring stability. When added to cigarettes, it decomposes to release 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, significantly enhancing the "sweet aftertaste" of cigarette smoke and highlighting the "sweet" and "smooth" taste characteristics of cigarettes. Compared with 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, it can also increase the caramel-like aroma of the smoke, improving the overall aroma of cigarettes, and has potential application value.

Description

Technical Field

[0001] This invention belongs to the field of tobacco flavoring synthesis technology, specifically relating to a 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester, a tobacco sweet flavoring raw material, and its application in cigarettes. Background Technology

[0002] The "sweetness" of cigarette smoke is a key indicator affecting the sensory quality and style characteristics of cigarettes. To highlight this characteristic, Chinese cigarette flavoring typically uses substances such as sugars, extracts, and Maillard reactants. These substances produce sweetness primarily because they contain or break down to produce small amounts of volatile sweet components such as pyranones and dehydrated sugars. However, the extremely low concentration of these sweet components transferred into the smoke results in a poor effect on highlighting the "sweetness" characteristic of Chinese cigarettes. Therefore, directly using volatile sweet components or precursors that can efficiently break down to produce sweet components in the flavoring of Chinese cigarettes, significantly increasing the content of sweet components in the smoke, is one of the effective means to highlight the "sweetness" characteristic of Chinese cigarettes.

[0003] 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) is widely found in cigarette smoke, Maillard reaction products, sugar cleavage products, and natural extracts. DDMP exhibits good water solubility and a prominent "sweet" taste, showing a significant positive correlation with the "sweetness" of cigarette smoke. It can significantly enhance the aftertaste of cigarette smoke, highlighting the "sweet" and "smooth" flavor characteristics of cigarettes. However, DDMP has poor stability, and its application as a sweet flavoring ingredient has not yet been realized. Literature and experimental studies have revealed that the exposed enol hydroxyl group at the 5-position is the main factor contributing to its deterioration; bonding the 5-position hydroxyl group can significantly improve its stability. Summary of the Invention

[0004] The purpose of this invention is to provide a 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester, a tobacco sweet flavoring raw material, and its application in cigarettes, in order to solve the problem that DDMP has poor stability, is easily deteriorated and damaged, and cannot be used as a sweet flavoring raw material.

[0005] This invention is achieved through the following technical solution:

[0006] A 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester, the structural formula of which is:

[0007]

[0008] The preparation method of the above-mentioned 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate includes the following steps:

[0009] 1) In a reaction flask, add bis(trichloromethyl) carbonate and organic solvent, and cool to -5 to 5°C under nitrogen protection;

[0010] 2) At the temperature in step 1), slowly add a mixture of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, an organic base, and an organic solvent, and raise the temperature to 20-40°C and react for 4-10 hours;

[0011] 3) After the reaction was completed, the organic mixture was washed with saturated sodium chloride solution, dried with anhydrous sodium sulfate, and the solvent was removed by vacuum distillation. The crude product was separated by silica gel column chromatography to obtain 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester (DDMP diester).

[0012] Preferably, the organic solvent in step 1) is one of dichloromethane, 1,2-dichloroethane, n-hexane, or 1,4-dioxane.

[0013] Preferably, the organic base in step 2) is one of triethylamine, pyridine, or diisopropylethylamine.

[0014] Preferably, the molar ratio of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, organic base and bis(trichloromethyl) carbonate in step 2) is 1:(1-1.5):(0.16-2).

[0015] A tobacco sweet flavoring ingredient, comprising at least the aforementioned 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester.

[0016] The application of the above-mentioned tobacco sweet flavoring raw materials in cigarettes.

[0017] Preferably, the alcohol solution of the tobacco sweet flavoring raw material is sprayed onto the tobacco shreds.

[0018] Preferably, the amount of 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate added to the tobacco sweet flavoring raw material is 1 to 50 ppm of the tobacco shreds.

[0019] The beneficial effects of this invention are:

[0020] This technical solution uses 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one as a raw material to prepare 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester through reaction with bis(trichloromethyl) carbonate. This type of compound exhibits good storage and flavoring stability. When added to cigarettes, it not only enhances the oral sweetness and improves the aftertaste comfort of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, effectively highlighting the "sweetness" characteristic of Chinese cigarettes, but also increases the caramel-like aroma and delicacy of the smoke, improving the overall aroma and character of the cigarette, thus possessing significant application value. Detailed Implementation

[0021] The technical solutions of the present invention will be described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and should not be construed as limiting the technical solutions of the present invention.

[0022] Example 1

[0023] bis(trichloromethyl) carbonate (1.09 g, 3.66 mmol) was dissolved in 20 mL of anhydrous dichloromethane, cooled to 0 °C, and a solution of DDMP (2.88 g, 20 mmol) and triethylamine (2.63 g, 26 mmol) in dichloromethane was slowly added dropwise. The mixture was then brought to 25 °C and reacted for 6 h. The organic phase was washed with saturated sodium chloride, dried over anhydrous Na₂SO₄, and the solvent was evaporated. The residue was subjected to silica gel column chromatography to give 2.26 g of DDMP diester as a white solid, with a yield of 72.4%.

[0024] Example 2

[0025] bis(trichloromethyl) carbonate (1.09 g, 3.66 mmol) was dissolved in 20 mL of anhydrous 1,2-dichloroethane. The solution was cooled to 0 °C, and a solution of DDMP (2.88 g, 20 mmol) and pyridine (2.05 g, 26 mmol) in 1,2-dichloroethane was slowly added dropwise. The mixture was then brought to 25 °C and reacted for 8 h. The organic phase was washed with saturated sodium chloride, dried over anhydrous Na₂SO₄, and the solvent was evaporated. The residue was subjected to silica gel column chromatography to give 2.18 g of DDMP diester as a white solid, with a yield of 69.9%.

[0026] Example 3

[0027] bis(trichloromethyl) carbonate (1.09 g, 3.66 mmol) was dissolved in 20 mL of anhydrous toluene, cooled to 0 °C, and a solution of DDMP (2.88 g, 20 mmol) and diisopropylethylamine (3.36 g, 26 mmol) in 1,4-dioxane was slowly added dropwise. The mixture was then heated to 30 °C and reacted for 8 h. The organic phase was washed with saturated sodium chloride, dried over anhydrous Na₂SO₄, and the solvent was evaporated. The residue was subjected to silica gel column chromatography to give 2.32 g of DDMP diester as a white solid, with a yield of 74.4%.

[0028] Example 4

[0029] bis(trichloromethyl) carbonate (1.32 g, 4.44 mmol) was dissolved in 20 mL of anhydrous dichloromethane, cooled to 0 °C, and a hexane solution of DDMP (2.88 g, 20 mmol) and triethylamine (3.03 g, 30 mmol) was slowly added dropwise. The mixture was then brought to 30 °C and reacted for 10 h. The organic phase was washed with saturated sodium chloride, dried over anhydrous Na₂SO₄, and the solvent was evaporated. The residue was subjected to silica gel column chromatography to give 1.41 g of DDMP diester as a white solid, with a yield of 45.2%.

[0030] Flavor performance test: Weigh out a certain amount of 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester (compound 1) and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) prepared in any of the above embodiments, and dilute them with ethanol to prepare a 5% solution for later use. Weigh 100g of unflavored blank cigarette tobacco, spread it evenly on a clean tray, and spray the compound 1 and DDMP solutions evenly on the tobacco to obtain cigarette tobacco with specific gravities of 5ppm, 10ppm, 20ppm, 30ppm and 50ppm of compound 1 and DDMP to tobacco, respectively. Seal and place for 4 hours, dry in an oven at 50℃, humidify with distilled water to the standard moisture content (12%), roll into standard cigarettes, and equilibrate the moisture content (humidity 60% ± 2%, temperature 22 ± 1℃) for 48 hours before evaluation smoking. The control sample was a blank cigarette, which was equilibrated for 48 hours under the same temperature and humidity conditions.

[0031] Table 1. Evaluation results of compound 1 and DDMP with added flavor.

[0032]

[0033]

[0034] Table 1 shows that both Compound 1 and DDMP significantly enhance the "sweetness" of cigarette smoke, highlighting the "sweet" and "smooth" taste characteristics of cigarettes, improving and modifying cigarette aroma, reducing irritation, improving the flavor, and making the aftertaste clean and comfortable. Compared to DDMP, Compound 1 can also increase the caramel-like aroma of the smoke, enriching the tobacco aroma and enhancing the overall fragrance of the cigarette, showing potential application value. However, when Compound 1 exceeds 30 ppm, it becomes cloyingly sweet and has a burnt smell, affecting the fragrance of the smoke, worsening the aftertaste, and causing discomfort. Recommended dosage: 10–30 ppm.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester, characterized in that, The structural formula is: The preparation method comprises the following steps: 1) adding bis(trichloromethyl) carbonate and an organic solvent in a reaction bottle, cooling to -5-5°C under nitrogen protection; 2) slowly adding a mixture of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, an organic base and an organic solvent at the temperature of step 1), and reacting at 30°C for 8-10 hours; 3) after the reaction is completed, the organic mixture is washed with saturated sodium chloride solution, dried with anhydrous sodium sulfate, and the solvent is removed under reduced pressure; the crude product is separated by silica gel column chromatography to obtain 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester.

2. The 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester according to claim 1, characterized in that, The organic solvent in step 1) is one of dichloromethane, 1,2-dichloroethane, n-hexane or 1,4-dioxane.

3. The 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester according to claim 1, characterized in that, The organic base in step 2) is one of triethylamine, pyridine or diisopropyl ethylamine.

4. The 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester according to claim 1, characterized in that, The molar ratio of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, the organic base and bis(trichloromethyl) carbonate in step 2) is 1:(1-1.5):(0.16-2).

5. The 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester according to any one of claims 1 to 4, as a component of a tobacco sweet flavor raw material, is applied in cigarettes.

6. Use in a cigarette according to claim 5, characterized in that, The alcohol solution of the tobacco sweet flavor raw material is sprayed on the tobacco.

7. Use in a cigarette according to claim 6, characterized in that, The addition amount of 2,3-dihydro-3-hydroxy-6-methyl-4H-pyran-4-one-5-O-carbonate diester in the tobacco sweet flavor raw material is 1-50 ppm of the mass of the tobacco.

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