Maltol carbonate and its synthesis method and application

Abstract

The application discloses maltol carbonate and a synthesis method and application thereof. Maltol is dissolved in dichloromethane, chloroformate or solid phosgene is added, and maltol carbonate is obtained after reaction. One or several kinds of maltol carbonate are mixed with propylene glycol and glycerol, and then applied to heating cigarette flavoring. Maltol carbonate is cracked and released when working in a heating cigarette, and the main role is to highlight the caramel sweet aroma of the heating cigarette and improve the oral comfort of the heating cigarette.

Description

Technical Field

[0001] This application relates to the field of fragrance technology, and in particular to a maltol carbonate, its synthesis method, and its application. Background Technology

[0002] Heated cigarettes rely on a heat source to generate mainstream smoke aerosols. Their heating rather than combustion nature results in a relatively simple decomposition reaction of the tobacco, limiting the release of aroma components and leading to problems such as insufficient aroma, low smoke concentration, and weak consumer satisfaction. How to compensate for the aroma in heated cigarettes, increase the quality and quantity of aroma, achieve uniform aroma release, and enhance consumer satisfaction is one of the key technical problems that urgently need to be solved in this field.

[0003] Maltol is a flavoring agent widely used in the food and cigarette industries, enhancing the sweet and caramel aroma of baked goods, candies, and cigarette smoke. However, maltol has a strong odor, which can mask the natural aroma of cigarettes when smelled. Therefore, some literature reports the synthesis of latent aroma compounds, maltol glycosides and zinc maltol complexes, for use in adding flavor to conventional cigarettes. The glycosidic and coordination bonds can cleave to release maltol during cigarette combustion. However, since the heating temperature range of heated cigarette tobacco is 100-260℃, the maltol glycosides and zinc maltol complexes described in the literature are difficult to effectively cleave during heated cigarettes. Therefore, it is necessary to develop latent aroma compounds of maltol that can be cleaved at the heating temperature of cigarettes. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a maltol carbonate, its synthesis method and application. The maltol carbonate of the present invention can be decomposed at the temperature of heated cigarettes to release maltol. When added to heated cigarettes, it can impart a distinct caramel sweet aroma.

[0005] The technical solution provided by this invention is as follows:

[0006] A maltol carbonate, wherein the molecular formula of the maltol carbonate is as follows:

[0007]

[0008] The group represented by R is selected from one of the following: n-pentyl, isobutyl, sec-butyl, tert-butyl, lauryl, hexadecyl, benzyl, and maltolyl.

[0009] A method for preparing maltol carbonate, wherein the preparation process of maltol carbonate is as follows: maltol is dissolved in dichloromethane, and then triethylamine (triethylamine is a base and acid-binding agent) and chloroformate are added in sequence. The reaction is carried out at room temperature until the reaction is complete. The solution after the reaction is washed, dried and concentrated under reduced pressure to obtain maltol carbonate.

[0010] The synthetic route for preparing the above-mentioned maltol carbonate is as follows:

[0011] .

[0012] Preferably, the chloroformate is one of n-amyl chloroformate, isobutyl chloroformate, sec-butyl chloroformate, tert-butyl chloroformate, lauryl chloroformate, hexadecyl chloroformate, and benzyl chloroformate.

[0013] Preferably, the obtained maltol carbonate is specifically maltol alkyl carbonate, wherein the maltol alkyl carbonate comprises substances with the following molecular formula:

[0014] .

[0015] Preferably, the molar ratio of the added maltol, triethylamine and benzyl chloroformate is 1:(1-1.5):(1-1.2).

[0016] A method for preparing maltol carbonate, wherein the preparation process of maltol carbonate is as follows: maltol is dissolved in a solvent, an organic base is added (the role of the organic base is to decompose solid phosgene to generate phosgene, and it can also act as an acid-binding agent to promote the reaction), and then a solution of solid phosgene is slowly added. The reaction is carried out at room temperature until the reaction is complete. The solution after the reaction is washed, dried, and concentrated under reduced pressure to obtain maltol carbonate.

[0017] The synthetic route for preparing the above-mentioned maltol carbonate is as follows:

[0018] .

[0019] Preferably, the obtained maltol carbonate is specifically maltol dicarbonate, with the following molecular formula:

[0020] .

[0021] Preferably, the organic base is one of triethylamine and pyridine, the solvent is one of dichloromethane and toluene, and the molar ratio of the added maltol, base and solid phosgene is 1:(1-1.5):(0.16-0.25).

[0022] A heated cigarette containing the maltol carbonate described above or the maltol carbonate prepared by the method described above.

[0023] Preferably, the maltol carbonate is added to the heated cigarette after being diluted with propylene glycol or glycerol. The maltol carbonate is added to the heated cigarette after being diluted to ensure its uniform distribution in the heated cigarette. The amount of maltol carbonate added is between one ten-thousandth and one thousandth of the mass of the heated cigarette tobacco.

[0024] This application has the following advantages over the prior art:

[0025] The method of this invention uses maltol as raw material to obtain maltol carbonate through a one-step reaction, with high yield and simple preparation method; the prepared maltol carbonate is basically odorless, which improves the disadvantage of maltol having a strong odor; the carbonate bond is a thermally unstable bond and is easily decomposed when heated. Therefore, maltol carbonate decomposes and releases maltol at the temperature of heated cigarettes. When added to heated cigarettes, it can impart a distinct caramel sweet aroma. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Example 1:

[0028] The synthesis methods for compounds 1a~1g are as follows:

[0029] Maltol (1.26 g, 10 mmol) was dissolved in 30 mL of dichloromethane, and triethylamine (1.11 g, 11 mmol) was added. The mixture was cooled to 0 °C, and chloroformate (10.5 mmol) was slowly added dropwise. After the addition was complete, the mixture was cooled to room temperature and the reaction proceeded to completion. The reaction solution was washed twice with saturated NaCl solution, dried over anhydrous Na2SO4, and concentrated under reduced pressure to give compound 1a~1 g.

[0030] NMR data of compound 1a: 1 H NMR (600 MHz, CDC l3 ) δ 7.68 (d, J = 5.7 Hz, 1H), 6.42 (d, J = 5.7 Hz, 1H), 4.27 (t, J = 6.8 Hz, 2H), 1.88 – 1.70 (m, 2H), 1.61– 1.30 (m, 4H), 0.92 (t, J = 7.0 Hz, 3H). 13 C NMR (150 MHz, CDC l3 ) δ 171.9,159.2, 154.2, 152.1, 139.1, 117.0, 69.8, 28.2, 27.7, 22.3, 14.9, 13.9.

[0031] NMR data for compound 1b: 1 H NMR (600 MHz, CDC l3 ) δ 7.68 (d, J = 5.7 Hz, 1H), 6.42 (d, J = 5.7 Hz, 1H), 4.06 (d, J = 6.7 Hz, 2H), 2.33 (s, 3H), 2.06 (dt, J= 13.5, 6.7 Hz, 1H), 1.00 (d, J = 6.8 Hz, 6H). 13 C NMR (150 MHz, CDC l3 ) δ171.9, 159.2, 154.2, 152.1, 139.1, 117.0, 75.5, 27.8, 18.8, 14.9.

[0032] NMR data of compound 1c: 1 H NMR (600 MHz, CDC l3 ) δ 7.68 (d, J = 5.7 Hz, 1H), 6.42 (d, J = 5.7 Hz, 1H), 5.09 – 4.48 (m, 1H), 2.32 (s, 3H), 1.81 – 1.72 (m,1H), 1.71 – 1.61 (m, 1H), 1.36 (d, J = 6.3 Hz, 3H), 0.99 (t, J = 7.5 Hz, 3H). 13 C NMR (150 MHz, CDC l3 ) δ 171.97, 159.13, 154.21, 151.71, 139.13, 117.00,78.72, 28.67, 19.19, 14.90, 9.52.

[0033] NMR data of compound 1d: 1 H NMR (600 MHz, CDC l3 ) δ 7.69 (d, J = 5.7 Hz, 1H), 6.40 (d, J = 5.7 Hz, 1H), 2.31 (s, 3H), 1.55 (s, 9H). 13 C NMR (150 MHz, CDC l3 )δ 172.1, 159.1, 154.2, 150.1, 139.0, 116.9, 84.5, 27.5, 14.9.

[0034] NMR data for compound 1e: 1 H NMR (600 MHz, CDC l3 ) δ 7.68 (d, J = 5.7 Hz, 1H), 6.42 (d, J = 5.7 Hz, 1H), 4.27(t, J = 6.8 Hz, 2H), 2.32 (s, 3H), 1.84 – 1.71(m, 2H), 1.30 (m, 18H), 0.90 (t, J = 7.0 Hz, 3H). 13 C NMR (150 MHz, CDC l3 ) δ171.9, 159.2, 154.2, 152.1, 139.1, 117.0, 71.4, 30.9, 29.7, 29.7, 29.6, 29.6,29.5, 29.2, 28.0, 26.6, 22.3, 14.6, 13.9.

[0035] NMR data of compound 1f: 1 H NMR (600 MHz, CDC l3 ) δ 7.67 (d, J = 5.7 Hz, 1H), 6.42 (d, J = 5.7 Hz, 1H), 4.26 (t, J = 6.8 Hz, 2H), 2.32 (s, 3H), 1.79 – 1.62(m, 2H), 1.26 (m, 26H), 0.88 (t, J = 7.0 Hz, 3H). 13 C NMR (150 MHz, CDC l3 ) δ171.9, 159.2, 154.2, 152.1, 139.1, 117.0, 69.8, 31.9, 29.7, 29.7, 29.7, 29.6,29.6, 29.5, 29.4, 29.2, 28.5, 25.6, 22.7, 14.9, 14.1.

[0036] NMR data for 1g of compound: 1 H NMR (600 MHz, CDC l3 ) δ 7.67 (d, J = 5.7 Hz, 1H), 7.36-7.43 (m, 5H), 6.42 (d, J = 5.8 Hz, 1H), 5.29 (s, 2H), 2.29 (s, 3H). 13CNMR (150 MHz, CDC l3 ) δ 171.8, 159.3, 154.3, 152.0, 139.1, 134.5, 128.7, 128.4,117.0, 71.7, 14.9.

[0037] Example 2:

[0038] The synthesis method of compound 1h is as follows:

[0039] Maltol (1.26 g, 10 mmol) was dissolved in dichloromethane, and triethylamine (12.12 g, 12 mmol) was added. A dichloromethane solution of solid phosgene (0.59 g, 0.2 mmol) was slowly added dropwise. The reaction was allowed to proceed to completion at room temperature. The reaction solution was washed twice with saturated NaCl solution, dried over anhydrous Na2SO4, concentrated under reduced pressure, and the residue was subjected to silica gel column chromatography with petroleum ether / ethyl acetate = 2 / 1 elution to give the compound after 1 h.

[0040] NMR data for 1g of compound: 1 H NMR (600 MHz, CDC l3 ) δ 7.70 (d, J = 5.8 Hz, 1H), 6.43 (d, J = 5.7 Hz, 1H), 2.47 (s, 3H). 13 C NMR (150 MHz, CDC l3 ) δ 171.5,160.2, 154.5, 139.1, 117.0, 15.1.

[0041] Example 3:

[0042] Thermal decomposition of compound 1d:

[0043] Sample preparation: A suitable amount of quartz wool was inserted into the pyrolysis quartz tube. Approximately 0.1 mg of the sample was weighed and added to the quartz tube, followed by the insertion of more quartz wool. The tube was then prepared for pyrolysis analysis. Anaerobic pyrolysis conditions: Initial temperature: 50 ℃; The temperature was increased to 150 ℃, 200 ℃, 250 ℃, and 300 ℃ at a rate of 20 ℃ / ms, and held for 15 s. The pyrolysis products were then introduced into GC-MS for analysis. The pyrolysis products are shown in Table 1, with maltol being the main component.

[0044] Table 1. Pyrolysis products of 1g of compound

[0045]

[0046] Example 4:

[0047] Thermal decomposition of 1g of compound:

[0048] Sample preparation: A suitable amount of quartz wool was inserted into the pyrolysis quartz tube. Approximately 0.1 mg of the sample was weighed and added to the quartz tube, followed by the insertion of more quartz wool. The tube was then prepared for pyrolysis analysis. Anaerobic pyrolysis conditions: Initial temperature: 50 ℃; The temperature was increased to 150 ℃, 200 ℃, 250 ℃, and 300 ℃ at a rate of 20 ℃ / ms, held for 15 s, and then the pyrolysis products were introduced into GC-MS for analysis. The pyrolysis products are shown in Table 2, mainly maltol and benzyl alcohol.

[0049] Table 2. Pyrolysis products of 1g of compound 2

[0050]

[0051] Example 5:

[0052] Application of maltol carbonate in heated cigarettes:

[0053] 200 mg of compound 1d was weighed and diluted to 2 mL with propylene glycol, and then diluted sequentially. The prepared solutions of different concentrations were uniformly added to heated cigarettes at gradient amounts of 0.01%, 0.02%, 0.05%, and 0.1% of the cigarette sheet mass. The results were compared with a blank sample and are shown in Table 3. Table 3 shows that the main function of compound 1d in cigarette flavoring is to enhance the caramel-sweet aroma and improve oral comfort.

[0054] Table 3. Comparative Assessment Results

[0055]

[0056] 200 mg of compound 1h was weighed and diluted to 2 mL with propylene glycol, and then diluted sequentially. The prepared solutions of different concentrations were uniformly added to heated cigarettes at gradient amounts of 0.01%, 0.02%, 0.05%, and 0.1% of the cigarette sheet mass. The results were compared with a blank sample and are shown in Table 4. Table 4 shows that the main function of compound 1h in cigarette flavoring is to enhance the caramel-sweet and floral aromas.

[0057] Table 4. Comparative Assessment Results

[0058]

[0059] Weigh 100 mg each of compounds 1d and 1h, and dilute to 2 mL with propylene glycol. Then dilute each compound sequentially. Add the prepared solutions of different concentrations evenly to heated cigarettes at gradient amounts of 0.01%, 0.02%, 0.05%, and 0.1% of the cigarette sheet mass. Compare with a blank sample for evaluation. The results are shown in Table 5. Table 5 shows that the main function of compounds 1d and 1h in cigarette flavoring is to enhance the caramel-sweet aroma and floral notes, and improve oral comfort.

[0060] Table 5. Comparative Assessment Results

[0061]

[0062] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A maltol carbonate, characterized in that, The molecular formula of the maltol carbonate is as follows: The group represented by R is selected from either tert-butyl or benzyl.

2. A method for preparing maltol carbonate as described in claim 1, characterized in that, The preparation process of the maltol carbonate is as follows: maltol is dissolved in dichloromethane, and then triethylamine and chloroformate are added in sequence. The reaction is carried out at room temperature until the reaction is complete. The solution after the reaction is washed, dried and concentrated under reduced pressure to obtain maltol carbonate.

3. The method for preparing maltol carbonate according to claim 2, characterized in that, Chloroformate is one of tert-butyl chloroformate and benzyl chloroformate.

4. The method for preparing maltol carbonate according to claim 3, characterized in that, The molar ratio of the added maltol, triethylamine and benzyl chloroformate is 1:(1-1.5):(1-1.2).

5. A heated cigarette, characterized in that, It contains the maltol carbonate as described in claim 1.

6. The heated cigarette according to claim 5, characterized in that, The maltol carbonate is diluted with propylene glycol or glycerol and then added to the heated cigarette. The amount of maltol carbonate added is between one ten-thousandth and one thousandth of the mass of the heated cigarette tobacco.

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