GAMMA-CAPROLACTONE PRECURSOR-AROMA COMPOUND AND PREPARATION METHOD AND USE THEREOF

Abstract

A γ-caprolactone precursor-aroma compound and a preparation method and uses thereof are disclosed. The preparation method specifically includes: dissolving γ-caprolactone in a sufficient amount of a solvent, adding an alkali at −78° C. to 0° C., stirring the resulting mixture to allow a reaction for 20 min or more, adding 2-acetylpyridine, further stirring at −78° C. to 0° C. to allow a reaction for 30 min or more, quenching the reaction, and finally subjecting the resulting reaction system to post-treatment, separation, and purification to obtain the target lactone precursor-aroma compound. The precursor-aroma compound of the present disclosure has stable properties in a normal temperature environment, can uniformly release an aroma under heating, increase and enrich the types of lactone fragrances, broaden an application range of lactone fragrances and acylpyridines, and overcome the defects of lactone and acylpyridine themselves, such as high volatility, small threshold, strong smell, and easy loss during processing.

Claims

1. A γ-caprolactone precursor-aroma compound with a structural formula as follows: ##STR00003##

2. A method of preparing the γ-caprolactone precursor-aroma compound according to claim 1, wherein a formula of a preparation reaction is as follows: ##STR00004## and the method comprises: dissolving γ-caprolactone in a solvent, adding an alkali at −78° C. to 0° C. to form a first mixture, conducting a first stir to the first mixture for 20 min or more, adding 2-acetylpyridine to form a second mixture, conducting a second stir to the second mixture at −78° C. to 0° C. for 30 min or more, quenching the second mixture, and finally subjecting the second mixture to a post-treatment, a separation, and a purification to obtain the γ-caprolactone precursor-aroma compound.

3. The method of preparing the γ-caprolactone precursor-aroma compound according to claim 2, wherein the solvent is one or more selected from the group consisting of diethyl ether, methyl tert-butyl ether (MTBE), tetrahydrofuran (THF), dioxane, methyltetrahydrofuran (MTHF), dichloromethane (DCM), 1,2-dichloroethane (1,2-DCE), dimethyl sulfoxide (DMSO), and petroleum ether.

4. The method of preparing the γ-caprolactone precursor-aroma compound according to claim 2, wherein the alkali is one or more selected from the group consisting of BuLi, LDA, LiHMDS, NaNH.sub.2, NaH, NaOC(CH.sub.3).sub.3, KOC(CH.sub.3).sub.3, NaOEt, and KOEt.

5. The method of preparing the γ-caprolactone precursor-aroma compound according to claim 2, wherein the γ-caprolactone, the alkali, and the 2-acetylpyridine are in a molar ratio of 1:(4-6):(1-1.5).

6. The method of preparing the γ-caprolactone precursor-aroma compound according to claim 2, wherein the quenching and the post-treatment comprise: adding a water to quench the second mixture, separating a resulting organic phase out, washing with a saturated brine, drying with anhydrous sodium sulfate, filtering, removing the solvent through a vacuum distillation, and subjecting a residue to the separation by a silica gel column chromatography.

7. The method of preparing the γ-caprolactone precursor-aroma compound according to claim 2, wherein the preparation reaction is conducted at −70° C. to 0° C.; the first stir is conducted for 20 min to 60 min; and the second stir is conducted for 30 min to 12 h.

8. A method of use of the γ-caprolactone precursor-aroma compound according to claim 1 as a fragrance, comprising: adding the γ-caprolactone precursor-aroma compound to a product with a release of an aroma during a combustion or a heating, wherein an amount of the γ-caprolactone precursor-aroma compound added to the product is 0.00001% to 10% of a weight of the product.

9. A method of use of the γ-caprolactone precursor-aroma compound according to claim 1 in a tobacco, comprising: adding the γ-caprolactone precursor-aroma compound to the tobacco, wherein an amount of the γ-caprolactone precursor-aroma compound added to the tobacco is 0.00001% to 2% of a weight of the tobacco.

10. The method of use of the γ-caprolactone precursor-aroma compound according to claim 9, wherein the γ-caprolactone precursor-aroma compound is added to the tobacco through top dressing, casing, or sheet-adding; or dissolving the γ-caprolactone precursor-aroma compound in a water or an alcohol or a mixture of the water and the alcohol to form a resulting solution, and spraying or injecting the resulting solution on/into the tobacco; and the tobacco is a mixed or flue-cured finished product or a component of a finished product formula.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0021] To describe the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings required for describing the embodiments or the prior art are briefly described below. Apparently, the accompanying drawing in the following description merely shows some embodiments of the present disclosure, and persons of ordinary skill in the art may still derive other accompanying drawings from these accompanying drawings without creative efforts.

[0022] FIGURE shows a proton nuclear magnetic resonance (1H NMR) of the precursor-aroma compound LSD8 of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the present disclosure clear, the technical solutions of the present disclosure will be described in detail below. Apparently, the described examples are merely a part, rather than all, of the examples of the present disclosure. All other embodiments obtained by persons of ordinary skill in the art based on the examples of the present disclosure without creative efforts should fall within the protection scope of the present disclosure.

Example 1

[0024] 25 mL (50 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −60° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF. The resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 30 min to obtain the reaction system. 1.21 g (10 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF. The resulting solution was slowly added dropwise to the above reaction system. The resulting mixture was stirred at −60° C. for 40 min, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.65 g of a target compound (NZ1) with a yield of 70%.

[0025] Test results were shown in the FIGURE, where the structural characterization was as follows:

[0026] .sup.1HNMR (400 MHz, CDCl.sub.3): δ, ppm 0.80-0.87 (m, 3H), 1.37-1.64 (m, 3H), 1.65-1.82 (m, 3H), 1.84-2.00 (m, 1H), 2.97-3.28 (m, 1H), 4.07-4.49 (m, 1H), 4.60-5.68 (m, 1H), 7.13-7.19 (m, 1H), 7.31-7.50 (m, 1H), 7.56-7.75 (m, 1H), 8.42-8.46 (m, 1H).

Example 2

[0027] 25 mL (50 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −20° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF. The resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 30 min to obtain the reaction system. 1.21 g (10 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF. The resulting solution was slowly added dropwise to the above reaction system, the resulting mixture was stirred at −60° C. for 40 min, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.04 g of a target compound (NZ1) with a yield of 44%.

Example 3

[0028] 30 mL (60 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −60° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF. The resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 30 min to obtain the reaction system. 1.82 g (15 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF, and the resulting solution was slowly added dropwise to the above reaction system. The resulting mixture was stirred at −60° C. for 40 min, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.69 g of a target compound (NZ1) with a yield of 72%.

Example 4

[0029] 20 mL (40 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −60° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF. The resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 30 min to obtain the reaction system. 1.21 g (10 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF, and the resulting solution was slowly added dropwise to the above reaction system. The resulting mixture was stirred at −60° C. for 40 min, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.37 g of a target compound (NZ1) with a yield of 58%.

Example 5

[0030] 25 mL (50 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −60° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF, the resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 60 min to obtain the reaction system. 1.21 g (10 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF, and the resulting solution was slowly added dropwise to the above reaction system. The resulting mixture was stirred at −60° C. for 40 min, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.63 g of a target compound (NZ1) with a yield of 69%.

Example 6

[0031] 25 mL (50 mmol) of lithium diisopropylamide was placed in a round-bottomed flask and stirred at −60° C. for 20 min. Subsequently, 1.1 g (10 mmol) of γ-caprolactone was dissolved in 10 mL of anhydrous THF. The resulting solution was slowly added dropwise to the lithium diisopropylamide solution, and the resulting mixture was stirred at −60° C. for 30 min to obtain the reaction system. 1.21 g (10 mmol) of 2-acetylpyridine was dissolved in 20 mL of anhydrous THF, the resulting solution was slowly added dropwise to the above reaction system, the resulting mixture was stirred at −60° C. for 12 h, and 30 mL of water was added for quenching. The resulting reaction system was concentrated to remove the THF, 100 mL of DCM was added for extraction, and the resulting organic phase was washed with saturated brine and dried with anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain a solid, and the solid was purified through column chromatography to obtain 1.53 g of a target compound (NZ1) with a yield of 65%.

Example 7

[0032] An NZ1 cigarette smoking evaluation experiment was now conducted to demonstrate that the compound of the present disclosure can improve the aroma of cigarette smoke. A specified amount of NZ1 was weighed and dissolved with ethanol. The resulting solution was added to a flue-cured tobacco shred at an amount of 0.003%, and the resulting mixture was rolled into an experimental cigarette. The same tobacco shred was taken, ethanol was added in the same proportion as above, and the resulting mixture was rolled into a blank cigarette. Comparative smoking was conducted, and results showed that, compared with the blank cigarette, the experimental cigarette had obvious sweetness, bean, and baking flavors, indicating an aroma enhancement effect.

[0033] In summary, the novel precursor-aroma compound of the present disclosure can uniformly release γ-caprolactone and acylpyridine to cigarette smoke when the cigarette is burned. The precursor-aroma compound has advantages such as a high boiling point, low volatility, and light smell and exhibits a prominent smoke flavoring effect when used for a cigarette. It can be seen that, when added to a cigarette, the precursor-aroma compound of the present disclosure can allow the cigarette to release a corresponding specific aroma and overcome the disadvantages of γ-caprolactone and acylpyridines themselves such as high volatility, small threshold, strong smell, and easy loss during processing.

[0034] The above are merely specific implementations of the present disclosure, and the protection scope of the present disclosure is not limited thereto. Any modification or replacement easily conceived by those skilled in the art within the technical scope of the present disclosure should fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims. In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any suitable manner, provided that there is no contradiction. To avoid unnecessary repetition, various possible combination modes of the present disclosure are not described separately. In addition, different implementations of the present disclosure can also be combined arbitrarily. The combinations should also be regarded as the content disclosed in the present disclosure, provided that they do not violate the ideas of the present disclosure.