Preparation method of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol and cut tobacco cigarette

Abstract

The present invention provides a method for preparing succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, comprising the following steps: A) mixing succinic anhydride and 4-methyl-5-thiazoleethanol in an organic solvent, reacting under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol monoester; B) reacting the succinic acid-4-methyl-5-thiazoleethanol monoester and a dehydrating agent in an organic solvent, and then reacting with ethyl maltol under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol ethyl maltol. The present application also provides a cigarette shred. The succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared by the present application can be decomposed to release tobacco-specific flavor components and burnt sweet flavor substances along with the burning and smoking of cigarettes, giving the smoke a strong burnt sweet fragrance, while reducing the loss of flavor components, and releasing more evenly from mouth to mouth, satisfying the consumer's smoking taste.

Description

Technical Field

[0001] The invention relates to the technical field of cigarettes, in particular to a preparation method of succinate-4-methyl-5-thiazoleethanol ethyl maltol and a cut tobacco cigarette. Background Art

[0002] As people pay more and more attention to the issue of "smoking and health", "low-harm, low-tar" cigarettes are sought after by consumers. However, while achieving the "harm reduction and tar reduction" effect of cigarettes, it inevitably affects the release of mainstream smoke aroma substances, thereby affecting the smoking quality of cigarettes. In order to make up for the aroma loss caused by harm reduction and tar reduction, adding flavors and fragrances to cigarettes has become an effective means in the cigarette field.

[0003] As an additive, ethyl maltol is widely used in the food industry. It has the functions of enhancing flavor and antiseptic properties, improving and enhancing the original flavor of spices, and blending with tobacco aroma to make the smoke have a soft and mellow taste, satisfying consumers' smoking taste. However, small molecule spices (such as ethyl maltol) have the characteristics of strong volatility, poor stability, and easy loss during cigarette processing and storage, which makes the aroma release uneven during the smoking process of cigarettes, resulting in unstable release of each puff in the cigarette, affecting consumers' smoking taste.

[0004] In order to solve the above problems, if more tobacco flavoring agents are simply used in the formula, the natural aroma of tobacco in the cigarette may be destroyed, and the fragrant, elegant, soft and mellow taste cannot be achieved. Therefore, the development of tobacco flavorings with long-lasting fragrance and uniform fragrance release has become a hot topic of research in recent years. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing succinic acid-4-methyl-5-thiazoleethanol ethyl maltol. The succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared in the present application can be used as a latent aroma substance of tobacco cigarettes, which can effectively improve the aroma quality of cigarettes, give cigarettes characteristic aroma, and reduce aroma loss.

[0006] In view of this, the present application provides a method for preparing succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, comprising the following steps:

[0007] A) mixing succinic anhydride and 4-methyl-5-thiazoleethanol in an organic solvent, and reacting under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol monoester;

[0008] B) reacting the succinic acid-4-methyl-5-thiazoleethanol monoester with a dehydrating agent in an organic solvent, and then reacting with ethyl maltol under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol ethyl maltol.

[0009] Preferably, in step A), the organic solvent is anhydrous dichloroethane, and the catalyst is 4-dimethylaminopyridine.

[0010] Preferably, in step A), the reaction temperature is 40-60° C. and the reaction time is 12-36 hours.

[0011] Preferably, in step A), the molar ratio of the succinic anhydride, the 4-methyl-5-thiazoleethanol and the catalyst is (1.2-1.5):1:(0.12-0.15).

[0012] Preferably, in step B), the dehydrating agent is selected from 1,3-dicyclohexylcarbodiimide, the catalyst is selected from 4-dimethylaminopyridine, and the organic solvent is selected from anhydrous dichloromethane.

[0013] Preferably, in step B), the molar ratio of the ethyl maltol, the succinic acid-4-methyl-5-thiazoleethanol monoester, the dehydrating agent and the catalyst is 1:(1.1-1.5):(1.3-1.6):(0.2-0.4).

[0014] Preferably, in step B), the ratio of the ethyl maltol to the organic solvent is 1 g: (10-15) mL.

[0015] Preferably, in step B), the reaction time in the organic solvent is 2 to 5 hours, the reaction time with ethyl maltol is 10 to 16 hours; and the reaction temperature is 20 to 35°C.

[0016] The present application also provides a tobacco shred cigarette, comprising spices and tobacco shreds, wherein the spices are succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared by the preparation method.

[0017] Preferably, the content of the succinic acid-4-methyl-5-thiazoleethanol ethyl maltol in the cut tobacco cigarette is 0.3-20wt%.

[0018] The present application provides a method for preparing succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, which uses ethyl maltol, 4-methyl-5-thiazoleethanol and succinic anhydride as raw materials, and prepares a latent aroma substance succinic acid-4-methyl-5-thiazoleethanol ethyl maltol through an esterification reaction. The succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared in the present application can be decomposed into a substance with an aroma at a certain temperature, and then it is added to cigarette shreds as a latent aroma substance. With the burning and smoking of the cigarette, the latent aroma substance can be decomposed to release tobacco-specific aroma components and burnt sweet aroma substances, which can give the smoke a strong burnt sweet aroma, reduce smoke irritation and impurities, and reduce the loss of aroma components caused by high-temperature evaporation. The release of each puff is more uniform, satisfying the consumer's smoking taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The NMR of compound 3a prepared in the present invention is 1 H NMR spectra;

[0020] Figure 2 The NMR of compound 3a prepared in the present invention is 13 C NMR spectra;

[0021] Figure 3 The infrared spectrum of compound 3a prepared in Example of the present invention;

[0022] Figure 4 The mass spectrum of compound 3a prepared in Example of the present invention;

[0023] Figure 5 This is the thermal decomposition ion flow diagram of compound 3a prepared in an example of the present invention at 300°C;

[0024] Figure 6 This is the thermal decomposition ion flow diagram of compound 3a prepared in an example of the present invention at 350°C;

[0025] Figure 7 This is the thermal decomposition ion flow diagram of compound 3a prepared in an example of the present invention at 400°C. DETAILED DESCRIPTION

[0026] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0027] In order to develop a tobacco flavor with long-lasting fragrance and uniform fragrance release, the present application first synthesized a succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, which can be cleaved to produce a variety of aroma latent aroma substances. Therefore, adding succinic acid-4-methyl-5-thiazoleethanol ethyl maltol to tobacco cigarettes can give the cigarettes a distinctive and lasting aroma, thereby improving the experience of smokers. Specifically, the embodiment of the present invention first discloses a preparation method of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, comprising the following steps:

[0028] A) mixing succinic anhydride and 4-methyl-5-thiazoleethanol in an organic solvent, and reacting under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol monoester;

[0029] B) reacting the succinic acid-4-methyl-5-thiazoleethanol monoester with a dehydrating agent in an organic solvent, and then reacting with ethyl maltol under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol ethyl maltol.

[0030] In the preparation process of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, the present application first mixes succinic anhydride and 4-methyl-5-thiazoleethanol in an organic solvent, reacts under the action of a catalyst, and obtains succinic acid-4-methyl-5-thiazoleethanol monoester. In the above process, the catalyst is specifically selected from 4-dimethylaminopyridine (DMAP); the organic solvent is anhydrous dichloroethane; the DMAP is a catalyst with a super-strong nucleophilic acylation effect, which can accelerate the esterification of succinic anhydride and 4-methyl-5-thiazoleethanol. With anhydrous dichloroethane as the organic solvent, succinic anhydride and 4-methyl-5-thiazoleethanol are more likely to react, and the reaction effect is excellent. The molar ratio of the succinic anhydride, the 4-methyl-5-thiazoleethanol and the catalyst is (1.2-1.5):1:(0.12-0.15); specifically, the molar ratio of the succinic anhydride, the 4-methyl-5-thiazoleethanol and the catalyst is (1.2-1.4):1:(0.13-0.14). The mass ratio of the succinic anhydride and the 4-methyl-5-thiazoleethanol to the volume of the anhydrous dichloroethane is 1 g:(3-6) mL, more specifically, the mass ratio of the succinic anhydride and the 4-methyl-5-thiazoleethanol to the volume of the anhydrous dichloroethane is 1 g:(4-5) mL.

[0031] The reaction temperature is 40-60°C and the reaction time is 12-36 hours; more specifically, the reaction temperature is 45-55°C and the reaction time is 24 hours.

[0032] The present application then reacts the succinic acid-4-methyl-5-thiazoleethanol monoester and a dehydrating agent in an organic solvent, and then reacts with ethyl maltol under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol ethyl maltol. In the above preparation process, the dehydrating agent is specifically selected from 1,3-dicyclohexylcarbodiimide (DCC), which first reacts with succinic acid-4-methyl-5-thiazoleethanol monoester, DCC obtains water and is converted into DCU, and succinic acid-4-methyl-5-thiazoleethanol monoester is dehydrated to generate anhydride. The catalyst is specifically selected from 4-dimethylaminopyridine (DMAP), which can accelerate the esterification reaction of the above-generated anhydride with ethyl maltol; the organic solvent is selected from anhydrous dichloromethane, which has a better reaction effect as a solvent. The molar ratio of the ethyl maltol, the succinic acid-4-methyl-5-thiazole ethanol monoester, the dehydrating agent and the catalyst is 1: (1.1-1.5): (1.3-1.6): (0.2-0.4), specifically, the molar ratio of the ethyl maltol, the succinic acid-4-methyl-5-thiazole ethanol monoester, the dehydrating agent and the catalyst is 1: (1.1-1.3): (1.4-1.5): (0.2-0.4). The ratio of the ethyl maltol to the organic solvent is 1 g: (10-15) mL; more specifically, the ratio of the ethyl maltol to the organic solvent is 1 g: (10-12) mL.

[0033] In the above reaction process, the reaction time in the organic solvent is 2 to 5 hours, and the reaction time with ethyl maltol is 10 to 16 hours; specifically, the reaction time in the organic solvent is 2 to 3 hours, and the reaction time with ethyl maltol is 12 to 16 hours.

[0034] The present application also provides a tobacco shred cigarette, which comprises a flavor and tobacco shreds, wherein the flavor is succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared by the preparation method described in the above scheme.

[0035] In the cut tobacco cigarette, the content of succinate-4-methyl-5-thiazoleethanolethyl maltol in the cut tobacco cigarette is 0.3-20wt%, specifically, the content of succinate-4-methyl-5-thiazoleethanolethyl maltol in the cut tobacco cigarette is 0.5-15wt%.

[0036] When the succinate-4-methyl-5-thiazoleethanolethyl maltol is applied to the cut tobacco cigarette, the succinate-4-methyl-5-thiazoleethanolethyl maltol is mixed with an organic solvent to prepare a 1-5wt% solution, which is then sprayed onto the cut tobacco to obtain the cut tobacco cigarette.

[0037] The invention discloses a preparation method of a latent aroma monomer for tobacco, succinic acid-4-methyl-5-thiazoleethanol ethyl maltol diester. The method comprises: using ethyl maltol, 4-methyl-5-thiazoleethanol and succinic anhydride as raw materials, and preparing a latent aroma substance with a burnt-sweet aroma through esterification; the burnt-sweet aroma source is ethyl maltol, and along with the burning and smoking of the cigarette, the latent aroma substance can be cracked to release tobacco characteristic aroma components and burnt-sweet aroma substances, which can give the smoke a strong burnt-sweet aroma and reduce the irritation and impurities of the smoke; on the other hand, the loss of aroma components caused by high-temperature evaporation is reduced, and the release of each puff is more uniform, satisfying the smoking taste of consumers.

[0038] In order to further understand the present invention, the preparation method and application of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol provided by the present invention are described in detail below in conjunction with the examples. The protection scope of the present invention is not limited by the following examples.

[0039] Example

[0040] A) Preparation of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol

[0041] 1) Weigh 1.20 g of succinic anhydride and dissolve it in anhydrous dichloroethane, add 1.43 g of 4-methyl-5-thiazoleethanol and 0.156 g of 4-dimethylaminopyridine (DMAP), mix and stir at 50° C. for 24 h, filter after the reaction, add 10% Na2CO3 solution to wash, take the upper aqueous solution, add 10% hydrochloric acid solution to adjust pH=3, extract the water layer three times with chloroform, dry it with anhydrous Na2SO4 overnight, filter and concentrate the filtrate under reduced pressure, separate by silica gel column chromatography, and obtain compound succinic acid-4-methyl-5-thiazoleethanol monoester 2a (light yellow solid) (2.176 g, 89.5%);

[0042] 2) Weigh 0.133g 2a and 0.136g DCC, add 8ml anhydrous dichloromethane, stir magnetically for 2h, add 0.07g ethyl maltol and 0.012g DMAP to the reaction solution, stir at room temperature, and monitor the reaction progress by TLC; after 12h, add excess glacial acetic acid to react with excess DCC, evaporate the solvent after 2h, and add ice water to terminate the reaction; filter the resulting compound, extract the aqueous layer twice with ethyl acetate, combine the ester layers, extract the ester layers with saturated NaHCO3 aqueous solution 3 times, extract them with saturated NaCl aqueous solution 2 times, wash until no bubbles are generated, back-extract with ice water 2 times, dry over anhydrous Na2SO4 overnight, filter and concentrate the filtrate under reduced pressure, separate by silica gel column chromatography, and obtain 0.096g, 52.59% compound succinic acid-4-methyl-5-thiazoleethanol ethyl maltol 3a (orange-yellow oily liquid).

[0043] B) Structural Characterization

[0044] The hydrogen spectrum data and carbon spectrum data of the obtained compound 3a are as follows: light yellow sticky solid, 1 HNMR (400MHz, CDCl3) δ8.60(s,1H),7.72(d,J=5.7Hz,1H),6.40(d,J=5.7Hz,1H),4.27(t,J=6.7Hz,2H),3.12(d,J =6.7Hz,2H),2.97–2.92(m,2H),2.77(t,J=6.7Hz,2H),2.61(q,J=7.6Hz,2H),2.42(s,3H),1.22(t,J=7.6Hz,3H); 13 C NMR (100MHz, CDCl3) δ172.07,171.82,169.31,163.37,154.38,149.98,149.90,137.74,126.57,116.72,64.3 5,28.92,28.48,25.70,22.17,14.86,10.78.IR(KBr)v:3096,2963,2920,1722,1654,1450,1211,1150,831cm - 1 .HRMS(ESI)Calcd.for C 17 H 19 NO6S,[M+H] + :366.1006,found[M+H] + :366.0993; specific Figure 1 , Figure 2 , Figure 3 and Figure 4 shown.

[0045] C) Olfaction Evaluation

[0046] A sensory evaluation panel was formed by five (two males and three females) from Henan Agricultural University, aged between 23 and 29 years old, healthy, and non-smoking (these members were selected based on their experience in evaluating volatile flavor compounds in food); GC-MS-O was used to evaluate the odor characteristics of ethyl maltol and compound 3a according to the "Sensory Evaluation Index Scoring Scale for Aroma Raw Materials"; when a peak appeared on the GC, a verbal description of the odor was obtained from the evaluation panel members at the same time, and the results are shown in Table 1;

[0047] Table 1 Status and odor characteristics of ethyl maltol and compound 3a

[0048]

[0049]

[0050] D) Analysis of pyrolysis products

[0051] The combustion process of cigarettes was simulated by the Py-GC / MS method, and the cracking products of compound 3a were detected. Setting different temperatures can more effectively simulate the combustion process of cigarettes to a certain extent. Three representative temperatures of 300°C, 350°C and 400°C were selected for analysis to monitor the pyrolysis of the compound in the air atmosphere. Each time, about 1 mg of the sample was placed in a quartz tube between two quartz cotton threads, and the pyrolysis products of the target compound were qualitatively and semi-quantitatively analyzed using the area normalization method using the NIST17 mass spectrometry database. The results are shown in Table 2. Figure 5 , Figure 6 and Figure 7 shown.

[0052] Table 2 Analysis results of thermal decomposition products of compound 3a

[0053]

[0054] As shown in Table 2, the target compound was pyrolyzed to obtain 4 products; at 300°C, 0.7% of succinic anhydride, 95.77% of ethyl maltol and 2.72% of 4-methyl-5-thiazoleethanol were obtained by pyrolysis; at 350°C, the content of 4-methyl-5-vinylthiazole accounted for 1.28% of the total content, succinic anhydride accounted for 0.94%, ethyl maltol accounted for 86.92% and 4-methyl-5-thiazoleethanol accounted for 9.19%; at 400°C, 4.42% of 4-methyl-5-vinylthiazole, 2.19% of succinic anhydride, 79.77% of ethyl maltol and 11.6% of 4-methyl-5-thiazoleethanol were obtained by pyrolysis.

[0055] It can be seen that at the above three temperatures, the target compound is cracked to produce ethyl maltol, and the content accounts for a relatively large proportion. Ethyl maltol has a caramel-like aroma and is a food additive that is allowed to be used. As the temperature increases, the relative content of ethyl maltol decreases, and the content of 4-methyl-5-vinylthiazole and 4-methyl-5-thiazoleethanol increases relatively. Among them, 4-methyl-5-vinylthiazole may be the product of the rearrangement of the 4-methyl-5-thiazoleethanol molecule, and both have a nutty aroma.

[0056] E) Research on the flavoring of target products in tobacco

[0057] With 95% ethanol as solvent, the target product succinic acid-4-methyl-5-thiazoleethanol ethyl maltol was prepared into a solution with a mass fraction of 1%; 0.5g, 1.0g, 5.0g, 10.0g and 15.0g of the above solution containing the target product were taken respectively, and then evenly sprayed into five portions of 100g blank Huanghelou soft blue tobacco without flavoring or adding materials, rolled, and 100 cigarettes of the same weight were selected for each, placed in a constant temperature and humidity box with a temperature of 22℃±1℃ and a humidity of 60%±2% for 48h, and evaluated for smoking. The control sample was blank Huanghelou soft blue tobacco (without flavoring or adding materials), and the control sample was also balanced for 48h under the same temperature and humidity conditions, and the results are shown in Table 3.

[0058] Table 3 Data table of flavoring and smoking evaluation results of compound 3a

[0059]

[0060]

[0061] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing succinic acid-4-methyl-5-thiazoleethanol ethyl maltol, comprising the following steps: A) mixing succinic anhydride and 4-methyl-5-thiazoleethanol in an organic solvent, and reacting under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol monoester; B) reacting the succinic acid-4-methyl-5-thiazoleethanol monoester and a dehydrating agent in an organic solvent, and then reacting with ethyl maltol under the action of a catalyst to obtain succinic acid-4-methyl-5-thiazoleethanol ethyl maltol as shown in the following formula; 2. The preparation method according to claim 1, characterized in that: In step A), the organic solvent is anhydrous dichloroethane, and the catalyst is 4-dimethylaminopyridine.

3. The preparation method according to claim 1, characterized in that: In step A), the reaction temperature is 40-60° C. and the reaction time is 12-36 hours.

4. The preparation method according to claim 1, characterized in that: In step A), the molar ratio of the succinic anhydride, the 4-methyl-5-thiazoleethanol and the catalyst is (1.2-1.5):1:(0.12-0.15).

5. The preparation method according to claim 1, characterized in that: In step B), the dehydrating agent is selected from 1,3-dicyclohexylcarbodiimide, the catalyst is selected from 4-dimethylaminopyridine, and the organic solvent is selected from anhydrous dichloromethane.

6. The preparation method according to claim 1 or 5, characterized in that: In step B), the molar ratio of the ethyl maltol, the succinic acid-4-methyl-5-thiazoleethanol monoester, the dehydrating agent and the catalyst is 1:(1.1-1.5):(1.3-1.6):(0.2-0.4).

7. The preparation method according to claim 1 or 5, characterized in that: In step B), the ratio of the ethyl maltol to the organic solvent is 1 g: (10-15) mL.

8. The preparation method according to claim 1, characterized in that: In step B), the reaction time in the organic solvent is 2 to 5 hours, the reaction time with ethyl maltol is 10 to 16 hours; and the reaction temperature is 20 to 35°C.

9. A tobacco cigarette comprising spices and tobacco, characterized in that: The fragrance is succinic acid-4-methyl-5-thiazoleethanol ethyl maltol prepared by the preparation method according to any one of claims 1 to 8.

10. The tobacco cigarette according to claim 9, characterized in that: The content of succinic acid-4-methyl-5-thiazoleethanol ethyl maltol in the cut tobacco cigarette is 0.3-20wt%.

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