A gamma-hydroxyvalerate alcohol ester compound, a synthesis method thereof and application thereof in tobacco

Abstract

The application discloses a gamma-hydroxyvaleric acid alcohol ester compound, a synthesis method thereof and application of the compound in tobacco, and a chemical structure general formula of the compound is The synthesis method is that acetylenic acid, alcohol spices, a condensing agent, a catalyst and a solvent are reacted under stirring to generate acetylenic acid alcohol ester compounds, and then gamma-hydroxyvaleric acid alcohol ester is obtained through hydrogenation reduction. The compound prepared by the application is stable at normal temperature and is not easy to volatilize, and after being heated, gamma-valerolactone and alcohol spices are uniformly released, and when the compound is added to cigarettes as a tobacco flavoring agent, the smoking quality of the cigarettes can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of flavors and fragrances, and particularly relates to a novel gamma-hydroxyvaleric acid alcohol ester compound, a synthesis method thereof, and a flavoring application of the compound in tobacco. Background Art

[0002] With the rapid development of fine chemicals and food industries, the market demand for new flavors is increasing. The development of new flavors with complex aromas, good durability and high stability is of great significance to the high-quality development of the flavor and fragrance industry.

[0003] Alcohol flavorings are a very important type of tobacco flavoring that plays a unique role in the cigarette industry. However, they are prone to oxidation and volatilization during use. For example, cinnamyl alcohol is a spice widely used in the food and tobacco industries, but it has the following problems: (1) It is highly volatile and easily dissipates during processing, making it difficult to maintain its aroma for a long time; (2) It is sensitive to temperature changes, and long-term high-temperature treatment will cause its aroma to weaken or lose; (3) It is easily oxidized and easily oxidized into cinnamaldehyde or cinnamic acid in the air, seriously affecting the aroma stability and safety of the product. In addition, common tobacco flavorings such as leaf alcohol and furfuryl alcohol also have the problem of easy volatilization and aroma loss. Therefore, esterification of alcohol flavorings can obtain new ester flavorings with complex aromas and high stability. This not only enriches the types of flavors but also meets the market demand for personalized aromas.

[0004] As a new type of latent fragrance, γ-hydroxyvaleric acid alcohol ester has great potential in aroma release and flavor expression due to its unique chemical structure. Compared with common fragrances, γ-hydroxyvaleric acid alcohol ester fragrances not only contain the milky and sweet aroma of γ-valerolactone, but also have the aroma characteristics of alcohol fragrances. They are also durable and stable, and can achieve longer aroma release in various products. When added to cigarettes, it is in a relatively stable state when the cigarette is not lit, but will undergo cracking when the cigarette is burning, releasing precursor aroma substances. The aroma remains consistent before and after the cigarette is smoked, thus achieving a stable aroma compensation effect.

[0005] However, current market research on γ-hydroxyvaleric acid alcohol esters is still relatively limited, especially in terms of their synthesis process and application effects. Therefore, the development of new fragrances based on γ-hydroxyvaleric acid alcohol esters will not only help enrich the fragrance market, but also meet consumer demand for high-quality, natural fragrances, and promote innovation and development in the fragrance industry. Summary of the Invention

[0006] The present application aims to provide a new monomer fragrance γ-hydroxyvaleric acid alcohol ester which is stable in chemical structure, keeps good fragrance at normal temperature, and can produce complex fragrance mainly with milk fragrance when heated, so as to improve the fragrance richness, delicate and soft smoke, and sensory quality of cigarettes when applied to cigarette products.

[0007] Another object of the present application is to provide an efficient synthesis method of the γ-hydroxyvaleric acid alcohol ester compound, which is simple in process and convenient for large-scale production.

[0008] To achieve the object, the present application adopts the following technical solutions.

[0009] The γ-hydroxyvaleric acid alcohol ester compound provided by the present application has the following general structure:

[0010]

[0011] The present application also provides a synthesis method of the γ-hydroxyvaleric acid alcohol ester compound, and the reaction formula is shown as follows:

[0012]

[0013] The synthesis method comprises the following steps:

[0014] In step 1, an acetylpropionic acid with a structure as shown in formula I, an alcohol fragrance with a structure as shown in formula II, a condensing agent, a catalyst and a first solvent are sequentially added into a round-bottom flask, and stirred at 20-50 DEG C for 2-6 h; after the reaction is completed, the obtained reaction solution is filtered, washed with saturated sodium bicarbonate solution and water twice, and the organic phase is dried with anhydrous sodium sulfate, filtered and rotary evaporated under reduced pressure, and then separated by silica gel column chromatography to obtain an intermediate product with a structure as shown in formula III;

[0015] In step 2, a second solvent is poured into a round-bottom flask containing the intermediate product obtained in step 1, and a reducing agent is slowly added under stirring, and reacted at 20-50 DEG C for 5-50 min; after the reaction is completed, the reaction solution is filtered and rotary evaporated under reduced pressure to remove the organic solvent, and then separated by silica gel column chromatography to obtain the γ-hydroxyvaleric acid alcohol ester with a structure as shown in formula IV.

[0016] Further, in step 1, the alcohol fragrance is at least one of phenethyl alcohol, citronellol, tetrahydrogeraniol, furfuryl alcohol, leaf alcohol and cinnamyl alcohol.

[0017] Furthermore, in step 1: the condensing agent is at least one of N,N'-dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), preferably dicyclohexylcarbodiimide; the catalyst is at least one of 4-dimethylaminopyridine (DMAP), 4-pyrrolidinylpyridine (PPY), and 1-hydroxybenzotriazole (HOBt), preferably 4-dimethylaminopyridine; the first solvent is at least one of tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, toluene, and dimethyl sulfoxide, preferably tetrahydrofuran; and the eluent used for silica gel column chromatography separation is composed of petroleum ether and ethyl acetate in a volume ratio of 1-15:1, preferably 4-10:1.

[0018] Furthermore, in step 1, the molar ratio of alcohol fragrance, levulinic acid, condensing agent and catalyst is 1:1.0-1.5:1.5-2.5:0.07-0.12, preferably 1:1.2:2.5:0.1.

[0019] Furthermore, in step 2: the reducing agent is at least one of borane ammonia complex, lithium aluminum tetrahydride, sodium borohydride, and diisobutylaluminum hydride, preferably borane ammonia complex; the second solvent is at least one of methanol, ethanol, tetrahydrofuran, dioxane and dimethyl sulfoxide, preferably methanol; the eluent used for the silica gel column chromatography separation is composed of petroleum ether and ethyl acetate in a volume ratio of 1-10:1, preferably 3:1.

[0020] Furthermore, in step 2, the molar ratio of the intermediate product to the reducing agent is 1:0.8-1.2, preferably 1:1.

[0021] The novel monomeric flavoring γ-hydroxyvaleric acid alcohol ester compound of the present invention can be dissolved in an alcohol or alcohol-water mixed solvent and then added to tobacco. The amount of the γ-hydroxyvaleric acid alcohol ester compound added is 0.0001% to 0.005% by weight of the tobacco, more preferably 0.0001%. The γ-hydroxyvaleric acid alcohol ester compound of the present invention is suitable for use in various types of tobacco, such as flue-cured cigarettes or novel tobacco products.

[0022] The beneficial effects of the present invention are embodied in:

[0023] 1. The present invention synthesizes a new flavoring γ-hydroxyvaleric acid alcohol ester compound for the first time. When added to cigarettes as a tobacco flavoring agent, it can enhance the richness and stability of the cigarette aroma, endowing the cigarettes with a variety of aromas, mainly milky, making the smoke delicate and soft, reducing impurities and irritation, and leaving the mouth clean and comfortable.

[0024] γ-Hydroxyvaleric acid alcohol ester is stable at room temperature and can steadily release γ-valerolactone and alcohol flavorings during smoking, effectively maintaining aroma consistency before and after smoking. Compared with a mixture of γ-valerolactone and alcohol flavorings, the addition of γ-Hydroxyvaleric acid alcohol ester prevents the reaction of γ-valerolactone with solvents such as ethanol and propylene glycol, which can cause changes in the flavor aroma before and after smoking.

[0025] 3. The synthesis method developed by the present invention has simple process, wide source of raw materials, mild reaction conditions, high yield of γ-hydroxyvaleric acid alcohol ester, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 γ-Hydroxyphenylethyl valerate 1 H NMR spectrum.

[0027] Figure 2 γ-Hydroxyphenylethyl valerate 13 C NMR spectrum.

[0028] Figure 3 γ-Hydroxycitronellol valerate 1 H NMR spectrum.

[0029] Figure 4 γ-Hydroxycitronellol valerate 13 C NMR spectrum.

[0030] Figure 5 Tetrahydrogeraniol γ-hydroxyvalerate 1 H NMR spectrum.

[0031] Figure 6 Tetrahydrogeraniol γ-hydroxyvalerate 13 C NMR spectrum.

[0032] Figure 7 γ-Hydroxyfurfuryl valerate 1 H NMR spectrum.

[0033] Figure 8 γ-Hydroxyfurfuryl valerate 13 C NMR spectrum.

[0034] Figure 9 γ-Hydroxyvaleric acid leaf ester 1 H NMR spectrum.

[0035] Figure 10 γ-Hydroxyvaleric acid leaf ester 13 C NMR spectrum.

[0036] Figure 11 γ-Hydroxycinnamyl valerate 1H NMR spectrum.

[0037] Figure 12 γ-Hydroxycinnamyl valerate 13 C NMR spectrum.

[0038] Figure 13 This is the thermogravimetric analysis (TG-DSC) of γ-hydroxyvalerate.

[0039] Figure 14 This is the GC spectrum of the thermal decomposition products of γ-hydroxycitronellol valerate at 300°C. DETAILED DESCRIPTION

[0040] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings and examples. The following is merely an example and illustration of the concept of the present invention. Those skilled in the art may make various modifications, supplements, or replace the specific embodiments described in the description with similar methods. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0041] Example 1: Synthesis of γ-hydroxyvaleric acid phenylethanol ester

[0042] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), phenylethanol (1.22 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and then filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 4:1) to give phenylethyl levulinate (colorless oil, 1.61 g, yield 73%).

[0043] Step 2: Add phenylethyl levulinate (1.61 g, 7.3 mmol) and 20 mL of methanol to a 50 mL round-bottom flask, slowly add NH3·BH3 (0.23 g, 7.3 mmol) under stirring, react at 25°C for 15 min, and filter. The reaction solution was evaporated under reduced pressure to remove the organic solvent, and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 3:1) to give γ-hydroxyvaleric acid phenylethyl ester (colorless oil, 1.59 g, yield 98%).

[0044] The product was characterized by NMR, and the data are as follows:

[0045] 1 H NMR (500MHz, CDCl3) δ7.30(t,J=7.4Hz,2H),7.25–7.19(m,3H),4.29(t,J=7.0Hz,2H),3.80–3.73(m,1H ),2.93(t,J=7.0Hz,2H),2.42(t,J=7.3Hz,2H),1.99(s,1H),1.79–1.65(m,2H),1.17(d,J=6.2Hz,3H); 13 C NMR (125MHz, CDCl3) δ174.1,137.9,129.0(2C),128.6(2C),126.7,67.3,65.0,35.1,33.9,30.8,23.6.

[0046] Example 2: Synthesis of γ-hydroxyvalerate citronellol ester

[0047] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), citronellol (1.56 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and then filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 8:1) to give citronellol levulinate (colorless oil, 2.06 g, yield 81%).

[0048] Step 2: Add citronellol levulinate (2.06 g, 8.1 mmol) and 20 mL of methanol to a 50 mL round-bottom flask, then slowly add NH3·BH3 (0.25 g, 8.1 mmol) under stirring, react at 25°C for 15 min, and filter. The reaction solution was evaporated under reduced pressure to remove the organic solvent, and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 4:1) to give γ-hydroxyvalerate citronellol ester (colorless oil, 2.03 g, yield 98%).

[0049] The product was characterized by NMR, and the data are as follows:

[0050] 1H NMR (500MHz, CDCl3) δ5.11–5.05(m,1H),4.16–4.06(m,2H),3.87–3.79(m,1H),2.49–2.38(m,2H),2.15(s,1H),2.05–1.91(m ,2H),1.84–1.63(m,6H),1.62–1.50(m,4H),1.48–1.40(m,1H),1.38–1.31(m,1H),1.23–1.13(m,4H),0.91(d,J=6.6Hz,3H); 13 C NMR (125MHz, CDCl3) δ174.3,131.4,124.6,67.3,63.2,37.0,35.5,34.0,30.9,29.5,25.8,25.4,23.6,19.5,17.2.

[0051] Example 3: Synthesis of γ-hydroxyvaleric acid tetrahydrogeraniol ester

[0052] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), tetrahydrogeraniol (1.54 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and then filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 is 10:1) to give tetrahydrogeraniol levulinate (colorless oil, 2.46 g, yield 96%).

[0053] Step 2: Add citronellol levulinate (2.46 g, 9.6 mmol) and 20 mL of methanol to a 50 mL round-bottom flask, then slowly add NH3·BH3 (0.30 g, 9.6 mmol) under stirring, react at 25°C for 15 min, and filter. The reaction solution was evaporated under reduced pressure to remove the organic solvent, and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 3:1) to give γ-hydroxyvaleric acid tetrahydrogeraniol ester (colorless oil, 2.43 g, yield 98%).

[0054] The product was characterized by NMR, and the data are as follows:

[0055] 1H NMR (500MHz, CDCl3) δ4.16–4.06(m,2H),3.87–3.80(m,1H),2.44(t,J=7.3Hz,2H),2.01(s,1H),1.84–1.62(m,3H),1.5 7–1.48(m,2H),1.46–1.38(m,1H),1.35–1.19(m,6H),1.18–1.08(m,3H),0.90(d,J=6.6Hz,3H),0.87(d,J=6.7Hz,3H); 13 C NMR (125MHz, CDCl3) δ174.4,67.4,63.3,39.3,37.2,35.6,34.0,30.9,29.9,28.1,24.7,23.6,22.8,22.7,19.6.

[0056] Example 4: Synthesis of γ-hydroxyfurfuryl valerate

[0057] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), furfuryl alcohol (0.98 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and then filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 is 4:1) to give furfuryl levulinate (colorless oil, 1.69 g, yield 86%).

[0058] Step 2: Furfuryl levulinate (1.69 g, 8.6 mmol) and 20 mL of methanol were added to a 50 mL round-bottom flask in sequence, and NH3·BH3 (0.27 g, 8.6 mmol) was slowly added under stirring. The mixture was reacted at 25°C for 15 min and then filtered. The reaction solution was evaporated under reduced pressure to remove the organic solvent and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 3:1) to give γ-hydroxyfurfuryl valerate (colorless oil, 1.67 g, yield 98%).

[0059] The product was characterized by NMR, and the data are as follows:

[0060] 1H NMR(500MHz, CDCl3)δ7.42(s,1H),6.42–6.34(m,2H),5.07(s,2H),3.85–3.77(m, 1H),2.47(t,J=7.3Hz,2H),2.09(s,1H),1.84–1.69(m,2H),1.19(d,J=6.2Hz,3H); 13 CNMR (125MHz, CDCl3) δ173.8,149.5,143.3,110.7,110.6,67.2,58.2,33.8,30.6,23.5.

[0061] Example 5: Synthesis of γ-hydroxyvalerate

[0062] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), leaf alcohol (1.00 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 is 6:1) to give leaf levulinate (colorless oil, 1.80 g, yield 91%).

[0063] Step 2: Add levulinic acid leaf alcohol ester (1.80 g, 9.1 mmol) and 20 mL of methanol in a 50 mL round-bottom flask, slowly add NH3·BH3 (0.28 g, 9.1 mmol) under stirring, react at 25°C for 15 min, and filter. The reaction solution is evaporated under reduced pressure to remove the organic solvent, and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 is 3:1) to give γ-hydroxyvaleric acid leaf alcohol ester (colorless oil, 1.77 g, yield 97%).

[0064] The product was characterized by NMR, and the data are as follows:

[0065] 1H NMR (500MHz, CDCl3) δ5.54–5.47(m,1H),5.34–5.27(m,1H),4.08(t,J=6.9Hz,2H),3.86–3.79(m,1H),2.44(td,J=7.4,1.5H z,2H),2.41–2.35(m,2H),2.15(s,1H),2.10–2.02(m,2H),1.84–1.69(m,2H),1.21(d,J=6.2Hz,3H),0.97(t,J=7.5Hz,3H); 13 C NMR (125MHz, CDCl3) δ174.3,134.7,123.7,67.3,64.1,33.9,30.8,26.8,23.6,20.7,14.3.

[0066] Example 6: Synthesis of γ-hydroxycinnamyl valerate

[0067] Step 1. To a 100 mL round-bottom flask, levulinic acid (1.39 g, 12 mmol), cinnamyl alcohol (1.34 g, 10 mmol), N, N'-dicyclohexylcarbodiimide (DCC, 5.16 g, 25 mmol), 4-dimethylaminopyridine (DMAP, 0.12 g, 1.0 mmol) and tetrahydrofuran (40 mL) were added in sequence, and the mixture was stirred at 25 ° C for 4 hours and filtered. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water in sequence, and the organic phase was dried over anhydrous sodium sulfate, filtered, and then evaporated under reduced pressure and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 is 4:1) to give cinnamyl levulinate (colorless oil, 2.07 g, yield 89%).

[0068] Step 2: Add cinnamyl levulinate (1.88 g, 8.9 mmol) and 20 mL of methanol to a 50 mL round-bottom flask, slowly add NH3·BH3 (0.27 g, 8.9 mmol) under stirring, react at 25°C for 15 min, and filter. The reaction solution is evaporated under reduced pressure to remove the organic solvent, and separated by silica gel column chromatography (eluent V 石油醚 :V 乙酸乙酯 γ-hydroxyvaleric acid cinnamyl ester (colorless oil, 2.02 g, yield 97%) was obtained.

[0069] The product was characterized by NMR, and the data are as follows:

[0070] 1H NMR (500 MHz, CDC13) δ 7.38 (d, J = 7.7 Hz, 2H), 7.32 (t, J = 7.5 Hz, 2H), 7.25 (t, J = 7.3 Hz, 1H), 6.65 (d, J = 15.9 Hz, 1H), 6.28 (dt, J = 15.9, 6.5 Hz, 1H), 4.74 (d, J = 6.5 Hz, 2H), 3.88 - 3.80 (m, 1H), 2.49 (t, J = 7.3 Hz, 2H), 2.02 (s, 1H), 1.87 - 1.71 (m, 2H), 1.21 (d, J = 6.2 Hz, 3H); 13 C NMR (125 MHz, CDC13) δ 174.0, 136.3, 134.3, 128.7 (2C), 128.2, 126.7 (2C), 123.2, 67.4, 65.2, 33.9, 30.8, 23.6.

[0071] Example 7: Thermal stability of citronellyl γ-hydroxyvalerate

[0072] The thermal gravimetric analysis of the target compound was carried out at 40-650°C, and the results are shown in Figure 13 The weight loss process of citronellyl γ-hydroxyvalerate mainly includes two stages: the first stage is the thermal stability stage, and the compound remains stable below 183°C and does not decompose; the second stage is the thermal decomposition stage, and rapid decomposition occurs at 183-326°C, with an obvious weight loss phenomenon, and the weight loss rate is the largest at 305°C. As the temperature rises, the weight loss rate decreases until the end of the weight loss process, and the total weight loss rate is 99.1%.

[0073] Example 8: Thermal cracking products of citronellyl γ-hydroxyvalerate

[0074] Taking citronellyl γ-hydroxyvalerate as an example, 2 mg of sample was accurately weighed and placed in a thermal cracking instrument. The sample was rapidly heated to 300°C at a heating rate of 20°C / ms under a helium atmosphere to simulate the conditions of cigarette combustion. The total ion chromatogram of the thermal cracking products is shown in Figure 14 The thermal cracking products are shown in Table 1 below:

[0075] Table 1 Thermal cracking results of citronellyl γ-hydroxyvalerate

[0076]

[0077] As can be seen from Figure 13 and Table 1, under the simulated conditions of cigarette combustion, citronellyl γ-hydroxyvalerate can release γ-valerolactone and citronellol well, increasing the milk, sweet and floral notes of the cigarette. At the same time, products such as citronellyl acetate and citronellene are generated, further enriching the aroma of the cigarette.

[0078] Example 9: Sensory Evaluation (Taking γ-Hydroxycitronellol Valerate as an Example)

[0079] Dissolve γ-valerolactone, citronellol and γ-hydroxyvalerate citronellol ester in 95% ethanol and prepare solutions with a mass concentration of 0.1%. Take 0.2g of each prepared 0.1% γ-valerolactone and citronellol solution, mix and evenly spray it into 100g of blank tobacco to prepare sample 1; take 0.1g and 0.2g of 0.1% γ-hydroxyvalerate citronellol ester solution and evenly spray it into 100g of blank tobacco, numbered as samples 2 and 3 respectively. After the above samples are placed for 2 hours, they are rolled into sample cigarettes. After the sample cigarettes are placed in a constant temperature and humidity chamber at a temperature of 22℃±1℃ and a humidity of 60%±2% for 48 hours, they are compared with the unflavored sample 0 placed under the same conditions for smoking. The sensory evaluation results are as follows:

[0080] Table 2 Sensory evaluation results of γ-hydroxyvalerate citronellol

[0081]

[0082] As shown in Table 2, compared to the mixed addition of γ-valerolactone and citronellol, γ-hydroxyvalerate citronellol has positive effects on improving aroma quality, smoothing smoke, and improving oral comfort, while also being added at a lower dosage of 1 ppm. Furthermore, γ-hydroxyvalerate citronellol is more stably released during the cigarette puffing process, maintaining aroma consistency from puff to puff.

[0083] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A γ-hydroxyvaleric acid alcohol ester compound, characterized in that The gamma-hydroxyvaleric acid alcohol ester compound is gamma-hydroxyvaleric acid citronellol ester.

2. A method for synthesizing γ-hydroxycitronellol valerate according to claim 1, characterized in that: The reaction formula is as follows: ； The synthesis method comprises the following steps: Step 1: Add levulinic acid represented by the structural formula of Formula I, citronellol, an alcohol fragrance represented by the structural formula of Formula II, a condensing agent, a catalyst, and a first solvent to a round-bottom flask in sequence, and stir the mixture at 20-50° C. for 2-6 hours. After the reaction is completed, filter the mixture, wash the resulting reaction solution with a saturated sodium bicarbonate solution and water in sequence, dry the organic phase over anhydrous sodium sulfate, filter, and evaporate under reduced pressure. Separate the mixture by silica gel column chromatography to obtain an intermediate product represented by the structural formula of Formula III. Step 2: Pour a second solvent into a round-bottom flask containing the intermediate product obtained in step 1, slowly add a reducing agent under stirring, and react at 20-50° C. for 5-50 min. After the reaction is completed, filter, evaporate the reaction solution under reduced pressure to remove the organic solvent, and separate by silica gel column chromatography to obtain γ-hydroxy citronellol valerate with the structural formula shown in Formula IV.

3. The synthesis method according to claim 2, characterized in that In step 1: the condensing agent is N,N' - at least one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide; the catalyst is at least one of 4-dimethylaminopyridine, 4-pyrrolidinylpyridine, and 1-hydroxybenzotriazole; the first solvent is at least one of tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, toluene, and dimethyl sulfoxide; and the eluent used for silica gel column chromatography separation is composed of petroleum ether and ethyl acetate in a volume ratio of 1-15:

1.

4. The synthesis method according to claim 2, wherein: In step 1, the molar ratio of alcohol fragrance, levulinic acid, condensing agent and catalyst is 1:1.0-1.5:1.5-2.5:0.07-0.

12.

5. The synthesis method according to claim 2, characterized in that In step 2, the reducing agent is at least one of borane ammonia complex, lithium aluminum tetrahydride, sodium borohydride, and diisobutylaluminum hydride; the second solvent is at least one of methanol, ethanol, tetrahydrofuran, dioxane, and dimethyl sulfoxide; and the eluent used for the silica gel column chromatography separation is composed of petroleum ether and ethyl acetate in a volume ratio of 1-10:

1.

6. The synthesis method according to claim 2, characterized in that: In step 2, the molar ratio of the intermediate product to the reducing agent is 1:0.8-1.

2.

7. Use of the gamma-hydroxycitronellol valerate according to claim 1 as a flavoring in tobacco.

8. The use according to claim 7, characterized in that: The gamma-hydroxy citronellol valerate is dissolved in alcohol or a mixed solvent of alcohol and water, and then added to tobacco. The added amount of the gamma-hydroxy citronellol valerate is 0.0001%-0.005% of the weight of the tobacco.

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