Novel farnesol glycoside precursor-aroma compound and application thereof

Abstract

The invention discloses a novel farnesol glycoside precursor-aroma compound and application thereof, and the structure of the farnesol glycoside precursor-aroma compound is as follows: # imgabs0. The farnesol glycoside precursor-aroma compound is a novel glycoside precursor-aroma spice, and can slowly release farnesol through combustion after being added into cigarettes; and the consistency of aroma quantity before and after smoking is ensured. In addition, the glycoside can be dehydrated after being heated to form farnesene, farnesene and other substances, and the substances enable the aroma of the cigarette to be richer. Therefore, the farnesol glycoside has a wide application prospect and is a potential precursor fragrance spice.

Description

Technical Field

[0001] The invention belongs to the field of perfume chemistry, and in particular relates to a novel farnesol glycoside latent aroma compound and application thereof. Background Art

[0002] Latent aroma flavors are a class of substances with large molecular weight and high boiling point. They do not have aroma or have weak aroma themselves, but can release compounds with aroma and fragrance through chemical hydrolysis, enzymatic hydrolysis or thermal decomposition (Principles and Applications of Tobacco Flavor Technology, 2009. Naturally occurring glycosides, 1998. Journal of Agricultural and Food Chemistry, 1990, 38: 1232-1236. Food Chemistry, 2016, 190: 412-418.). Glycosides, as a kind of latent aroma flavor, are widely present in plants, especially in tobacco (Fragrance Chemistry and Technology, 1991.). Glycosides in tobacco release aroma components through thermal decomposition and breaking glycosidic bonds, which contribute to the aroma of cigarettes. In addition, glycosylation of certain flavors can also overcome the problem of unstable aroma release caused by the volatilization of flavors.

[0003] Farnesol is a chain sesquiterpenoid high-grade fragrance and bioactive compound, which is widely found in the flowers, leaves, stems and other parts of plants, especially in some Chinese herbal medicines and spice plants, such as Cinnamomum camphora, Magnolia flower, loquat leaf, etc. It has a pleasant, mild and delicate floral aroma with lily of the valley characteristics. Farnesol is widely used in the fields of medicine, food, cosmetics and cigarette flavoring (Forest Products Chemistry and Industry, 2005, 25: 175-178. Forest Products Chemical Industry News, 2005, 05: 34-38.). When used as a raw material for tobacco flavor, farnesol can not only give cigarettes a fresh, floral and sweet fragrance, but also significantly improve the quality and amount of cigarette fragrance, and can also reduce the irritation and impurities of cigarettes, which has a positive effect on cigarette smoke. However, farnesol has a low boiling point, and the aroma release is unstable after adding it to cigarettes. Glycosylation of farnesol can effectively improve its aroma release stability and can be used as a stable latent aroma flavor in cigarette flavoring. Summary of the invention

[0004] The purpose of the present invention is to provide a novel farnesol glycoside latent aroma compound and its application. The farnesol glycoside latent aroma compound of the present invention has weak volatility and can slowly release aroma substances such as farnesol after pyrolysis. In addition, farnesene and farnesene and other substances can also be cracked. Therefore, the application of the novel farnesol glycoside in cigarette products can not only bring the fragrance of farnesol, such as fragrance and floral fragrance, but also give other fragrances to cigarettes, greatly increase the richness of fragrance, and thus improve the sensory quality of cigarettes.

[0005] The farnesol glycoside latent aroma compound of the present invention has a structure as shown below:

[0006]

[0007] The method for synthesizing the farnesol glycoside latent aroma compound of the present invention is to use farnesol and α-bromotetraacetyl glucose as starting materials, generate farnesol tetra-O-acetyl-β-D-glucoside under the action of additives, and then hydrolyze under alkaline conditions to generate farnesol-β-D-glucoside latent aroma compound. Specifically, it comprises the following steps:

[0008] Step 1: Farnesol, α-bromotetraacetyl glucose, additives and organic solvents are mixed, reacted at 25-100° C. for 1-24 hours, and thin layer chromatography (TLC) is used for monitoring during the reaction. After the reaction is completed, the filtrate is filtered, and the filtrate is concentrated by rotary evaporation under reduced pressure. Farnesol tetra-O-acetyl-β-D-glucoside is separated and purified by column chromatography.

[0009] Step 2: Farnesol tetra-O-acetyl-β-D-glucoside, a base and an organic solvent are mixed, and the mixture is reacted at 25 to 100° C. for 1 to 24 hours. The reaction is monitored by thin layer chromatography (TLC). After the reaction is completed, an acid solution is added to neutralize the system, and the mixture is filtered. The filtrate is concentrated by rotary evaporation under reduced pressure, and the farnesol-β-D-glucoside is separated and purified by column chromatography.

[0010] In step 1, every time 5 to 10 mmol of farnesol is reacted with 5 to 20 mmol of α-bromotetraacetylglucose, 5 to 20 mmol of an additive and 20 to 100 mL of an organic solvent are used.

[0011] In step 1, the additive is silver carbonate (Ag 2 CO 3 ), silver nitrate (AgNO 3 ), silver sulfate (Ag 2 SO 4 ), more preferably silver carbonate.

[0012] In step 1, the organic solvent is petroleum ether (PE), ethyl acetate (EtOAc), acetonitrile (MeCN), dichloromethane (DCM), tetrahydrofuran (THF), diethyl ether (Et 2 At least one of methanol (MeOH) and dichloromethane is more preferred.

[0013] In step 1, the column chromatography separation refers to column chromatography under air pressure, the silica gel is 200-300 mesh, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 100-1:1.

[0014] In step 2, for every 1 to 5 mmol of farnesol tetra-O-acetyl-β-D-glucoside, 0.1 to 5 mmol of a base, 0.1 to 5 mmol of an acid and 20 to 100 mL of an organic solvent are used for the hydrolysis reaction.

[0015] In step 2, the base is sodium methoxide (CH 3 ONa), sodium ethoxide (C 2 H 5 ONa), potassium carbonate (K 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), more preferably sodium methoxide.

[0016] In step 2, the acid is hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), acetic acid (AcOH), more preferably hydrochloric acid.

[0017] In step 2, the organic solvent is petroleum ether (PE), ethyl acetate (EtOAc), acetonitrile (MeCN), dichloromethane (DCM), tetrahydrofuran (THF), diethyl ether (Et 2 At least one of methanol (MeOH) and methanol is more preferably used.

[0018] In step 2, the column chromatography separation refers to column chromatography under air pressure, the silica gel is 200-300 mesh, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 100-1:1.

[0019] The farnesol glycoside latent aroma compound of the invention is used as a latent aroma fragrance in the preparation of cigarettes.

[0020] Specifically, the farnesol glycoside latent aroma compound is dissolved in alcohol or an alcohol / water mixed solvent and then evenly sprayed onto the tobacco shreds. The amount of the latent aroma compound added is 0.0001% to 0.1% by weight of the tobacco shreds, preferably 0.001%.

[0021] The beneficial effects of the present invention are embodied in:

[0022] 1. This invention designs and synthesizes the farnesol glycoside latent aroma compound for the first time. By organically combining farnesol with glucose, the thermal stability of farnesol is significantly improved. Its thermal stability is explored by thermogravimetric (TG-DTG) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) tests; its flavoring effect is explored by sensory evaluation. These works provide a reference for the development of new latent aroma fragrances.

[0023] 2. Taking farnesol glycoside as an example, compared with farnesol, farnesol glycoside has improved thermal stability, and its thermal cracking process is carried out in two steps. The maximum thermal weight loss temperatures of the two steps are 210℃ and 307℃, corresponding to the dehydration and cleavage of the glycoside and the cleavage of the glycosidic bond, respectively. The main substances released by thermal cracking are farnesene, farnesene and farnesol. It can be seen that in addition to effectively releasing farnesol, a large amount of farnesene and farnesene are also produced during the combustion and pyrolysis of farnesol glycoside. These substances can significantly increase the richness of cigarette aroma and improve the sensory quality of cigarettes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Farnesol glycoside 1 HNMR spectrum.

[0025] Figure 2 Farnesol glycoside 13 C NMR spectrum.

[0026] Figure 3 This is the infrared spectrum of farnesol glycoside.

[0027] Figure 4 This is the mass spectrum of farnesol glycoside.

[0028] Figure 5 This is the TG-DTG spectrum of farnesol.

[0029] Figure 6 This is the TG-DTG spectrum of farnesol glycoside.

[0030] Figure 7 This is the GC spectrum of the thermal decomposition products of farnesol glycoside at 300°C.

[0031] Figure 8 This is the GC spectrum of the thermal decomposition products of farnesol glycoside at 600°C.

[0032] Fig. 9 This is the GC spectrum of the thermal decomposition products of farnesol glycoside at 900°C. DETAILED DESCRIPTION

[0033] 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.

[0034] Example 1: Preparation of farnesol-β-D-glucoside

[0035]

[0036] 1. Add farnesol (2.22 g, 10.0 mmol), α-bromotetraacetyl glucose (4.92 g, 12.0 mmol) and Molecular sieve (5 g), 40 mL of dichloromethane, and the newly prepared silica gel-loaded Ag were added during stirring. 2 CO 3 (4.14 g, 15.0 mmol), refluxed and stirred at 40 ° C for 7 h under light-proof conditions to react, thin layer chromatography (TLC) was used for monitoring during the reaction, and a mixed solvent of V (petroleum ether): V (ethyl acetate) = 3: 1 was used as a developing solvent. After the reaction was completed, stirring was stopped, filtered, and the filtrate was concentrated by rotary evaporation under reduced pressure to obtain a yellow-brown paste, which was separated by 200-300 mesh silica gel column chromatography and eluted with a mixed solvent of V (petroleum ether): V (ethyl acetate) = 3: 1. After rotary evaporation, farnesol tetra-O-acetyl-β-D-glucoside was obtained, a white viscous substance, 1.18 g of a white solid, and a yield of 22.0%.

[0037] 2. Sodium methoxide (23.8 mg, 0.44 mmol) and 100 mL of methanol were added to the reaction flask in sequence, followed by the farnesol tetra-O-acetyl-β-D-glucoside (1.18 g, 2.2 mmol) obtained in the previous step, and the reaction was carried out for 3 h at room temperature. After the reaction was completed, a methanol solution of hydrochloric acid was added to neutralize the system to pH = 6.5. The solvent was removed under reduced pressure, and eluted with a mixed solvent of V (dichloromethane): V (methanol) = 12:1 to obtain 0.77 g of farnesol-β-D-glucoside as a white solid with a yield of 94.6%.

[0038] 1 H NMR (400 MHz, CDCl 3 )δ5.37(s,1H),5.10(s,2H),4.71(bs,3H),4.35(s,2H),4.22(s,1H),3.84(s,2H),3.62(s,1H) ,3.53(s,1H),3.41(s,1H),3.27(s,1H),3.03(bs,1H),2.05(s,6H),1.68(s,6H),1.60(s,6H); 13 C NMR (100 MHz, CDCl 3)δ141.45,135.31,131.22,124.28,123.71,119.65,101.41,76.41,75.57,7 3.24,69.31,65.88,61.34,39.66,26.70,26.45,25.64,17.63,16.43,15.96. Chemical Formula:C 21 H 36 O 6 .IR(KBr),ν / cm -1 :3390(-OH),2930(-CH 3 ),1670(-C=C-),1080(-COC-),1040(-COC-). HRMS(ESI)m / z[M+Na] + Calcd for C 20 H 24 NO 6 :407.2404;Found:407.2395.

[0039] Example 2: Comparison of thermal stability of farnesol-β-D-glucoside

[0040] Weigh 5.0 mg of farnesol glycoside and farnesol respectively into an alumina pan, and use a blank alumina pan as control. Use high-purity nitrogen as carrier gas with a flow rate of 100 mL / min, and heat from 30°C to 800°C at a rate of 20°C / min to record the TG-DTG curve. Figure 5 , 6 It can be seen that the DTG curve of farnesol has only one absorption peak, indicating that the thermal cracking process of farnesol is completed in one step. The temperature when farnesol mass loss begins is about 147℃, and the temperature of final mass loss is about 318℃, with a weight loss of 99.46%; at the same time, it can be obtained from the DTG curve that the temperature when its mass loss rate is the largest is 242℃, which is close to the boiling point of farnesol, proving that farnesol has basically boiled and vaporized after this temperature, so the mass loss rate is the largest. The DTG curve of farnesol glycoside has three absorption peaks. The first absorption peak is mainly caused by the volatilization of water and residual solvent in the sample; the second stage is the dehydration and cleavage of glycoside glycoside, and the main cleavage products in this stage are farnesene and farnesene, etc. From the DTG curve, it can be obtained that the temperature when the mass loss rate is the largest in this stage is about 210℃; the third stage is the cleavage of glycosidic bond in glycoside, and farnesol is released by cleavage in this stage. From the DTG curve, it can be obtained that the temperature when the mass loss rate is the largest in this stage is about 307℃. The whole process resulted in a weight loss of 94.07%.

[0041] Example 3: Thermal cracking products of target products

[0042] Weigh an appropriate amount of farnesol glycoside, place it in a small hollow quartz tube, and perform instantaneous pyrolysis at 300, 600, and 900°C, respectively. The pyrolysis products are directly introduced into GC / MS by carrier gas He for separation and identification. The total ion current of the pyrolysis products of farnesol glycoside is shown in Figure 7 , 8 , 9. The types of pyrolysis products of farnesol glycoside at three different temperatures are basically the same, mainly including farnesol, farnesene, farnesene, etc. These compounds are produced by the glycoside breaking glycosidic bonds and the dehydration and thermal pyrolysis of glycosides. The analysis of thermal pyrolysis products shows that farnesol glycoside can effectively release farnesol and other characteristic flavor components when heated, and these substances can greatly increase the richness of cigarette aroma after entering the mainstream smoke.

[0043] Example 4: Evaluation of the flavoring of the target product in tobacco

[0044] Take 0.01g of farnesol glycoside sample and farnesol sample converted to equimolar amount, dissolve in 10.0g anhydrous ethanol respectively, add 10μL of flavoring to each cigarette, the starting point of flavoring is 1mm, and the ending point of flavoring is 54mm. The control sample is a blank cigarette injected with an equal amount of anhydrous ethanol. The flavored cigarettes are balanced in an environment with a temperature of (22±1)℃ and a relative humidity of (60±3)% for 48h, and then the sensory quality is evaluated according to GB 5604.4-2005 "Cigarette Part 4: Sensory Technical Requirements". The evaluation team is composed of 10 judges from the Smoking Evaluation Committee of the Technical Center of Anhui China Tobacco Industry Co., Ltd. Qualitative description is made according to indicators such as gloss, aroma, harmony, impurities, irritation and aftertaste, and the sensory experience during the entire smoking process is recorded, and the difference before and after smoking is compared. From the sensory evaluation results in the table below, it can be seen that the three samples have obvious differences in aroma, coordination, miscellaneous smell, irritation and aftertaste; compared with the blank sample, the cigarettes with farnesol and farnesol glycoside added have sufficient aroma, delicate and soft smoke, both of which increase the smoky aroma and fresh aroma of the cigarettes, and at the same time, the coordination, miscellaneous smell and irritation are improved; the aroma of the cigarettes with farnesol glycoside added has good consistency before and after, and the difference between the front and back sections of smoking is not obvious. In addition, since the glycosides will dehydrate to form farnesene and farnesene after heating, this leads to a richer aroma of cigarettes with farnesol glycoside added. It can be seen that cigarettes with farnesol glycoside added can not only provide characteristic floral aroma and fresh aroma to improve the taste, but also ensure the consistency of the front and back sections of smoking, and its aroma is richer than that of cigarettes with farnesol added.

[0045]

[0046] The above are merely exemplary embodiments of the present invention and are 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 novel farnesol glycoside latent aroma compound, characterized in that Its structure is as follows:

2. The method for synthesizing the farnesol glycoside latent aroma compound according to claim 1, characterized in that: Farnesol and α-bromotetraacetyl glucose are used as starting materials, farnesol tetra-O-acetyl-β-D-glucoside is generated under the action of additives, and then hydrolyzed under alkaline conditions to generate farnesol-β-D-glucoside latent aroma compound; The synthetic route is as follows:

3. The synthesis method according to claim 2, characterized in that The steps include: Step 1: mixing farnesol, α-bromotetraacetyl glucose, an additive and an organic solvent, reacting at 25-100° C., monitoring the reaction by thin layer chromatography, filtering after the reaction is completed, concentrating the filtrate by rotary evaporation under reduced pressure, and separating and purifying by column chromatography to obtain farnesol tetra-O-acetyl-β-D-glucoside; Step 2: Farnesol tetra-O-acetyl-β-D-glucoside, a base and an organic solvent are mixed and reacted at 25-100° C. The reaction process is monitored by thin layer chromatography. After the reaction is completed, an acid solution is added to neutralize the system, the system is filtered, and the filtrate is concentrated by rotary evaporation under reduced pressure. Farnesol-β-D-glucoside is obtained by separation and purification by column chromatography.

4. The synthesis method according to claim 3, characterized in that: In step 1, the additive is at least one of silver carbonate, silver nitrate and silver sulfate.

5. The synthesis method according to claim 3, characterized in that: In step 1, the column chromatography separation refers to column chromatography under air pressure, the silica gel is 200-300 mesh, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 100-1:

1.

6. The synthesis method according to claim 3, characterized in that: In step 2, the base is at least one of sodium methoxide, sodium ethoxide, potassium carbonate and sodium carbonate.

7. The synthesis method according to claim 3, characterized in that: In step 2, the acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, and acetic acid.

8. The synthesis method according to claim 3, characterized in that: In step 2, the column chromatography separation refers to column chromatography under air pressure, the silica gel is 200-300 mesh, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 100-1:

1.

9. Use of the farnesol glycoside latent aroma compound according to claim 1 as a latent aroma flavorant in the preparation of cigarettes.

10. The use according to claim 9, characterized in that: The farnesol glycoside latent aroma compound is dissolved in alcohol or alcohol / water mixed solvent, and then evenly sprayed on the tobacco shreds. The addition amount of the farnesol glycoside latent aroma compound accounts for 0.0001% to 0.1% of the weight of the tobacco shreds.

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