Gamma-hydroxypentanoic acid alcohol ester compound, synthesis method thereof and application of gamma-hydroxypentanoic acid alcohol ester compound in tobacco

Abstract

The invention discloses a gamma-hydroxypentanoic acid alcohol ester compound and a synthesis method and application thereof in tobacco, the chemical structural general formula is # imgabs0, and the synthesis method comprises the following steps: levulinic acid, alcohol perfume, a condensing agent, a catalyst and a solvent react under a stirring condition to generate a levulinic acid alcohol ester compound, and then the levulinic acid alcohol ester compound is subjected to hydrogenation reduction to obtain gamma-hydroxypentanoic acid alcohol ester. The compound prepared by the invention is stable and not easy to volatilize at normal temperature, uniformly releases gamma-valerolactone and alcohol perfume after being heated, and can effectively improve the smoking quality of cigarettes when being added into the cigarettes as a tobacco flavor enhancer.

Description

Technical Field

[0001] The invention belongs to the field of flavors and fragrances, and specifically relates to a novel gamma-hydroxyvaleric acid alcohol ester compound and 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 growing. The development of new flavors with complex aromas, good persistence 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 flavorings, playing a unique role in the cigarette industry, but they are easy to oxidize and volatilize 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 dissipated 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 easy to oxidize and is easily oxidized into cinnamaldehyde or cinnamic acid in the air, which seriously affects 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, by subjecting alcohol flavorings to esterification reaction, a new type of ester flavoring with complex aroma and high stability can be obtained, which can not only enrich the types of flavors, but also meet the market demand for personalized aroma.

[0004] As a new type of latent fragrance, γ-hydroxyvaleric acid alcohol ester has a unique chemical structure that gives it great potential in aroma release and flavor performance. 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, and have good durability and stability, and can achieve a longer aroma release in various products. When added to cigarettes, it is in a relatively stable state when the cigarette is not lit, but it will crack when the cigarette is burning, and release the precursor aroma substances, and the aroma before and after the cigarette is smoked remains consistent, thus achieving a stable aroma compensation effect.

[0005] However, the current research on γ-hydroxyvaleric acid alcohol esters in the market is still relatively limited, especially in terms of its synthesis process, application effect, etc. Therefore, the development of new flavors based on γ-hydroxyvaleric acid alcohol esters will not only help enrich the flavor market, but also meet consumers' demand for high-quality, natural flavors and promote the innovative development of the flavor industry. Summary of the invention

[0006] The purpose of the present invention is to provide a new type of monomer fragrance γ-hydroxyvaleric acid alcohol ester which has a stable chemical structure and good aroma retention at room temperature, but can produce a composite aroma with milk aroma as the main flavor when heated. The application of γ-hydroxyvaleric acid alcohol ester in cigarette products can improve the richness of cigarette aroma, make smoke delicate and soft, and enhance the sensory quality of cigarettes.

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

[0008] In order to achieve the purpose, the present invention adopts the following technical scheme:

[0009] The present invention provides a γ-hydroxyvaleric acid alcohol ester compound, whose general structural formula is as follows:

[0010]

[0011] The present invention also provides a method for synthesizing the γ-hydroxyvaleric acid alcohol ester compound, and the reaction formula thereof is as follows:

[0012]

[0013] The synthesis method comprises the following steps:

[0014] Step 1, add levulinic acid as shown in formula I, alcohol flavor as shown in formula II, condensation agent, catalyst and first solvent into a round-bottom flask in sequence, and stir and react at 20-50° C. for 2-6 hours; after the reaction is completed, filter, wash the obtained reaction solution with saturated sodium bicarbonate solution and water twice in sequence, dry the organic phase over anhydrous sodium sulfate, filter, evaporate under reduced pressure, and separate by silica gel column chromatography to obtain an intermediate product as shown in formula III;

[0015] Step 2, pouring the second solvent into the round-bottom flask containing the intermediate product obtained in step 1, slowly adding the reducing agent under stirring, and reacting for 5-50 minutes at 20-50° C.; after the reaction is completed, filtering, and removing the organic solvent from the reaction solution by vacuum rotary evaporation, and separating by silica gel column chromatography to obtain γ-hydroxyvaleric acid alcohol ester with a structural formula as shown in formula IV.

[0016] Furthermore, in step 1: the alcohol fragrance is at least one of phenylethyl alcohol, citronellol, tetrahydrogeraniol, furfuryl alcohol, leaf alcohol, cinnamyl alcohol and the like.

[0017] Further, 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; 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 flavor, levulinic acid, condensation 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 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 monomer flavor γ-hydroxyvaleric acid alcohol ester compound of the present invention can be dissolved in alcohol or alcohol-water mixed solvent when used, and then added to tobacco, and the added amount of the γ-hydroxyvaleric acid alcohol ester compound is 0.0001%-0.005% by weight of the tobacco, and more preferably 0.0001%. The γ-hydroxyvaleric acid alcohol ester compound of the present invention is suitable for various types of tobacco, such as flue-cured tobacco cigarettes or novel tobacco products.

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

[0023] 1. The present invention synthesizes a new flavor γ-hydroxyvaleric acid alcohol ester compound for the first time. Adding it to cigarettes as a tobacco flavoring agent can enhance the richness and stability of the aroma of cigarettes, endow cigarettes with a variety of aromas mainly based on milky aroma, make the smoke delicate and soft, reduce impurities and irritation, and make the oral cavity clean and comfortable.

[0024] 2. γ-Hydroxyvaleric acid alcohol ester is stable at room temperature. It can stably release γ-valerolactone and alcohol flavors during the smoking process of cigarettes, and better maintain the consistency of aroma before and after smoking. Compared with the mixture of γ-valerolactone and alcohol flavors, the addition of γ-hydroxyvaleric acid alcohol ester can avoid the reaction of γ-valerolactone with solvents such as ethanol and propylene glycol, which causes the aroma of the flavor to change before and after.

[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-Hydroxyvaleric acid phenethyl ester 1 H NMR spectrum.

[0027] Figure 2 γ-Hydroxyvaleric acid phenethyl ester 13 C NMR spectrum.

[0028] Figure 3 Citronellol gamma-hydroxyvalerate 1 H NMR spectrum.

[0029] Figure 4 Citronellol gamma-hydroxyvalerate 13 C NMR spectrum.

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

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

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

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

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

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

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

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

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

[0039] Fig.14 This is the GC spectrum of the thermal decomposition products of γ-hydroxyvalerate citronellol ester at 300°C. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments. The following content is only an example and explanation of the concept of the present invention. The technicians in the relevant technical field make various modifications or supplements to the specific implementation cases described or replace them 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 should all fall within the protection scope of the present invention.

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

[0042] Step 1: Add 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) to a 100 mL round-bottom flask, stir at 25 ° C for 4 h, and filter. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water, 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 phenethyl levulinate (colorless oil, 1.61 g, yield 73%).

[0043] Step 2: Add phenethyl levulinate (1.61 g, 7.3 mmol) and 20 mL of methanol into a 50 mL round-bottom flask, and slowly add NH 3 ·BH 3 (0.23 g, 7.3 mmol), 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-hydroxyvaleric acid phenethyl 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 (500 MHz, CDCl 3 )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 (125 MHz, CDCl 3 )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: Add 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) to a 100 mL round-bottom flask, stir at 25 ° C for 4 h, and filter. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water, 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: In a 50 mL round-bottom flask, citronellol levulinate (2.06 g, 8.1 mmol) and 20 mL of methanol were added in sequence, and NH 3 ·BH 3 (0.25 g, 8.1 mmol), 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 4:1) to give γ-hydroxyvaleric acid citronellol ester (colorless oil, 2.03 g, yield 98%).

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

[0050] 1 H NMR (500 MHz, CDCl 3 )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),1.8 4–1.63(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 (125 MHz, CDCl 3 )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: Add 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) to a 100 mL round-bottom flask, stir at 25 ° C for 4 h, and filter. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water, 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 obtain tetrahydrogeraniol levulinate (colorless oil, 2.46 g, yield is 96%).

[0053] Step 2: In a 50 mL round-bottom flask, citronellol levulinate (2.46 g, 9.6 mmol) and 20 mL of methanol were added in sequence, and NH 3 ·BH 3 (0.30 g, 9.6 mmol), 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-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] 1 H NMR (500 MHz, CDCl 3 )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),1.57–1.48(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 (125 MHz, CDCl 3 )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: Add 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) to a 100 mL round-bottom flask, stir at 25 ° C for 4 h, and filter. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water, 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 furfuryl levulinate (colorless oil, 1.69 g, yield 86%).

[0058] Step 2: In a 50 mL round-bottom flask, add furfuryl levulinate (1.69 g, 8.6 mmol) and 20 mL of methanol in sequence, and slowly add NH 3 ·BH 3 (0.27 g, 8.6 mmol), 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-hydroxyvaleric acid furfuryl ester (colorless oil, 1.67 g, yield 98%).

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

[0060] 1H NMR (500 MHz, CDCl 3 )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, CDCl 3 )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-hydroxyvaleric acid leaf alcohol ester

[0062] Step 1: Add 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) to a 100 mL round-bottom flask, stir at 25 ° C for 4 h, and filter. The resulting reaction solution was washed twice with saturated sodium bicarbonate solution and water, 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 6:1) to obtain levulinic acid phytol ester (colorless oil, 1.80 g, yield 91%).

[0063] Step 2: In a 50 mL round-bottom flask, add levulinic acid ester (1.80 g, 9.1 mmol) and 20 mL of methanol in sequence, and slowly add NH 3 ·BH 3 (0.28 g, 9.1 mmol), 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 obtain 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] 1 H NMR (500 MHz, CDCl 3)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=7.4,1.5Hz,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 (125 MHz, CDCl 3 )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-hydroxyvaleric acid cinnamyl ester

[0067] Step 1: Add 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) to a 100 mL round-bottom flask, stir and react for 4 h at 25 ° C, and filter. 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 cinnamyl levulinate (colorless oil, 2.07 g, yield 89%).

[0068] Step 2: In a 50 mL round-bottom flask, cinnamyl levulinate (1.88 g, 8.9 mmol) and 20 mL of methanol were added in sequence, and NH 3 ·BH 3 (0.27 g, 8.9 mmol), 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 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] 1 H NMR (500 MHz, CDCl 3)δ7.38(d,J=7.7Hz,2H),7.32(t,J=7.5Hz,2H),7.25(t,J=7.3Hz,1H),6.65(d,J=15.9Hz,1H),6.28(dt,J=15.9,6.5Hz,1H ),4.74(d,J=6.5Hz,2H),3.88–3.80(m,1H),2.49(t,J=7.3Hz,2H),2.02(s,1H),1.87–1.71(m,2H),1.21(d,J=6.2Hz,3H); 13 C NMR (125 MHz, CDCl 3 )δ174.0,136.3,134.3,128.7(2C),128.2,126.7(2C),123.2,67.4,65.2,33.9,30.8,23.6.

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

[0072] Taking γ-hydroxyvalerate citronellol ester as an example, the target compound was subjected to thermogravimetric analysis at 40-650°C. The results are as follows: Fig.13 The weight loss process of γ-hydroxyvalerate citronellol ester is mainly divided into two stages: the first stage is the thermal stability stage, the compound maintains structural stability below 183°C and does not decompose; the second stage is the thermal decomposition stage, it decomposes rapidly in the temperature range of 183-326°C, and obvious weight loss occurs, and the weight loss rate is the largest at 305°C. As the temperature increases, the weight loss rate decreases until the weight loss process ends, and the total weight loss rate is 99.1%.

[0073] Example 8: Thermal cleavage products of γ-hydroxycitronellol valerate

[0074] Taking γ-hydroxyvalerate citronellol ester as an example, 2 mg of sample was accurately weighed and placed in a pyrolysis instrument to simulate cigarette smoking conditions. The temperature was rapidly raised to 300°C at a heating rate of 20°C / ms in a helium atmosphere. The total ion current of the pyrolysis product was shown in Fig.14 The pyrolysis products are shown in Table 1 below:

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

[0076]

[0077] Depend on Fig.13 As shown in Table 1, under the simulated cigarette burning state, γ-hydroxyvalerate citronellol ester can well release γ-valerolactone and citronellol, increasing the aroma of cigarettes such as milk, sweet and floral. At the same time, products such as citronellyl acetate and citronellene are generated, further enriching the aroma of cigarettes.

[0078] Example 9: Sensory evaluation (taking γ-hydroxyvalerate citronellol ester as an example)

[0079] Dissolve γ-valerolactone, citronellol and γ-hydroxyvaleric acid citronellol ester in 95% ethanol and prepare solutions with a mass concentration of 0.1%. Take 0.2g of the prepared 0.1% γ-valerolactone and citronellol solutions respectively, mix and spray evenly on 100g of blank tobacco to prepare sample 1; take 0.1g and 0.2g of 0.1% γ-hydroxyvaleric acid citronellol ester solution and spray evenly on 100g of blank tobacco, numbering samples 2 and 3 respectively. Place the above samples for 2 hours and then roll them 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 with the mixed addition of γ-valerolactone and citronellol, γ-hydroxyvaleric acid citronellol has a positive effect in improving the aroma texture, delicate and soft smoke, oral comfort, etc., and the addition amount is lower, which is 1ppm. In addition, γ-hydroxyvaleric acid citronellol can be more stably released during the smoking process of cigarettes, and the consistency of aroma before and after smoking is better maintained.

[0083] The above description is only 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 should be included in the protection scope of the present invention.

Claims

1. A γ-hydroxyvaleric acid alcohol ester compound, characterized in that The general structural formula is:

2. A method for synthesizing the γ-hydroxyvaleric acid alcohol ester compound 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 as shown in formula I, alcohol flavor as shown in formula II, condensation agent, catalyst and first solvent into a round-bottom flask in sequence, and stir to react at 20-50° C. for 2-6 hours; after the reaction is completed, filter, wash the obtained reaction solution with saturated sodium bicarbonate solution and water in sequence, dry the organic phase over anhydrous sodium sulfate, filter, evaporate under reduced pressure, and separate by silica gel column chromatography to obtain an intermediate product as shown in formula III; Step 2, pouring the second solvent into the round-bottom flask containing the intermediate product obtained in step 1, slowly adding the reducing agent under stirring, and reacting for 5-50 minutes at 20-50° C.; after the reaction is completed, filtering, and removing the organic solvent from the reaction solution by vacuum rotary evaporation, and separating by silica gel column chromatography to obtain γ-hydroxyvaleric acid alcohol ester with a structural formula as shown in formula IV.

3. The synthesis method according to claim 2, characterized in that In step 1: the alcohol fragrance is at least one of phenylethyl alcohol, citronellol, tetrahydrogeraniol, furfuryl alcohol, leaf alcohol and cinnamyl alcohol.

4. The synthesis method according to claim 2, characterized in that In step 1: the condensing agent is at least one of N,N'-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.

5. The synthesis method according to claim 2, characterized in that: In step 1, the molar ratio of alcohol flavor, levulinic acid, condensation agent and catalyst is 1:1.0-1.5:1.5-2.5:0.07-0.

12.

6. 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.

7. 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.

8. Use of the γ-hydroxyvaleric acid alcohol ester compound according to claim 1 as a flavoring in tobacco.

9. The use according to claim 8, characterized in that: The gamma-hydroxyvaleric acid alcohol ester compound is dissolved in alcohol or a mixed solvent of alcohol and water, and then added into tobacco. The added amount of the gamma-hydroxyvaleric acid alcohol ester compound is 0.0001%-0.005% of the weight of the tobacco.

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