Spicy, green and baked multi-vitamin aroma characteristic compound and preparation method thereof

Abstract

The invention relates to the technical field of essence, and particularly discloses a spicy, green and baked multi-vitamin aroma characteristic compound and a preparation method thereof. The name of the compound is 2, 3-diethyl-5-isobutyl-6-methoxypyrazine, and due to the fact that the compound is extremely obvious in fragrance, extremely low in fragrance threshold value, high in molecular weight, long in fragrance holding time and good in stability, the compound has important beneficial application in the field of fragrance blending, especially in the field of research and development of spicy-green fragrance-baking fragrance composite fragrance type spicy essence and the field of daily chemicals. The perfuming agent can be used for washing agents, air fresheners, perfumes and other daily chemical products, and can also be used for perfuming paper, plastics, leather, fabrics and the like. The compound can be used for preparing a base, and then the base is prepared into daily chemical essence, and the compound can also be directly used as a raw material for preparing the daily chemical essence.

Description

Technical Field

[0001] This invention relates to the technical field of fragrances, and specifically discloses a multi-dimensional aroma characteristic compound of spicy, green, and roasted aromas and its preparation method. Background Technology

[0002] With the upgrading of consumption and the improvement of living standards, fragrances and flavorings, due to their naturally rich aroma experience and emotional value, are increasingly becoming core elements in personal care and home environment construction, and are deeply penetrating into diverse consumption scenarios such as perfumes, cosmetics, home fragrances, aromatherapy, and food and beverages. In this process, pyrazine compounds, with their ultra-low aroma threshold and high aroma intensity, have become key technical components in the formulation of high-end fragrances. These substances are naturally present in baked goods, coffee, nuts, and other systems, and can accurately simulate complex aromas such as roasted aromas, green peppers, and earthy notes, significantly improving the realism and complexity of fragrances.

[0003] Despite the continued rise in market demand for fragrances, current spicy fragrance products still have some shortcomings. For example, existing spicy fragrances are limited in terms of aroma complexity and olfactory layering. Traditional formulas rely on spicy ingredients (such as dill aldehyde, isoeugenol, and guaiacol), which, due to their simple molecular structures, can only present a flat spicy tone (such as a simple spiciness or a monotonous smokiness), making it difficult to accurately reproduce the layered changes of natural spices. This aroma uniformity leads to olfactory fatigue when using blended fragrances and fails to meet the demand for complex and recognizable fragrances in high-end daily chemical products. Furthermore, many fragrance ingredients do not perform well in terms of scent persistence, easily evaporating in a short time. While this is beneficial for expressing the top notes of the fragrance, as it evaporates, the aroma is insufficient in the body and base notes of the fragrance, causing the natural feel of the spicy fragrance to gradually weaken and disappear over time, failing to meet consumers' demand for natural and long-lasting fragrances. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-dimensional aroma characteristic compound of spicy, green, and roasted aroma and its preparation method. In a first aspect, this invention discloses a multi-dimensional aroma characteristic compound of spicy, green, and roasted aroma, using the following technical solution: A compound with a spicy, green, roasted aroma and multidimensional aroma characteristics, named 2,3-diethyl-5-isobutyl-6-methoxypyrazine, has the following chemical structure: .

[0005] This compound, due to its extremely pronounced aroma, very low aroma threshold, high molecular weight, long-lasting fragrance, and good stability, has significant and beneficial applications in the perfumery field, especially in the development of spicy-green-roasted aroma complexes and in the daily chemical industry. It can be used in detergents, air fresheners, perfumes, and other daily chemical products, and can also be applied to scenting paper, plastics, leather, and textiles. This compound can be used to formulate fragrance bases, which can then be used to formulate daily chemical fragrances, or it can be used directly as a raw material for formulating daily chemical fragrances.

[0006] Secondly, this invention discloses a method for preparing a multi-dimensional aroma characteristic compound of spicy, green, and roasted aroma, using the following technical solution: A method for preparing a multidimensional aroma characteristic compound of spicy, green, and roasted aroma, comprising the following steps: (1) 2-amino-4-methylpentanamide hydrochloride and 3,4-hexanedione were subjected to a condensation reaction in the presence of a solvent and under alkaline conditions. After the reaction was completed, the reaction was terminated by acid, neutralized by base, and washed by salting out. The organic phase was concentrated by rotary evaporation to obtain 5,6-diethyl-3-isobutylpyrazine-2-ol. (2) The 5,6-diethyl-3-isobutylpyrazine-2-ol obtained in step (1) is subjected to a halogenation reaction with a chlorinating agent. After the reaction is completed, the reaction solution is adjusted to strong alkalinity with an alkaline solution, and then extracted, salted out and washed. The organic phase is concentrated by rotary evaporation to obtain 2-chloro-5,6-diethyl-3-isobutylpyrazine. (3) The 2-chloro-5,6-diethyl-3-isobutylpyrazine obtained in step (2) was subjected to methoxylation reaction with sodium methoxide in methanol solution. After the reaction was completed, the organic phase was extracted, washed by salting out, concentrated by rotary evaporation, and the fraction was collected by vacuum distillation to obtain 2,3-diethyl-5-isobutyl-6-methoxypyrazine.

[0007] Preferably, in step (1), before mixing 2-amino-4-methylpentanamide hydrochloride and 3,4-hexanedione, the system is cooled to -20±2℃. During the dropwise addition of alkali solution, the reaction temperature is maintained at ≤10℃. After the addition is complete, the system is returned to room temperature and stirred. The pH at which the acid terminates is adjusted to 1~2. Cooling the reaction system to -20±2℃ reduces the reaction rate, preventing violent reactions and the formation of byproducts. Maintaining the temperature at ≤10℃ during the dropwise addition of alkali solution further controls the reaction rate and ensures a stable reaction. Returning the system to room temperature and stirring after the dropwise addition promotes full contact of the reactants and improves the conversion rate.

[0008] Preferably, in step (2), the chlorinating agent includes phosphorus oxychloride and phosphorus pentachloride. Phosphorus oxychloride is added first at the initial stage of the reaction, followed by phosphorus pentachloride added in batches for a reflux reaction. By using phosphorus oxychloride and phosphorus pentachloride as chlorinating agents, sufficient chlorine atoms can be provided for the halogenation reaction. Adding phosphorus oxychloride first at the initial stage gently initiates the reaction, avoiding an overly vigorous reaction. Subsequent batches of phosphorus pentachloride further promote the reaction, ensuring the completeness of the halogenation reaction. This stepwise addition method allows for better control of reaction conditions, reduces the formation of byproducts, and improves the yield and purity of the target product.

[0009] Preferably, in step (2), after the reaction is completed, the temperature is lowered and the extractant is added, followed by neutralization with a weak base. During neutralization, the temperature is ≤5℃, and then the pH is adjusted to 12-13 with an alkaline solution. Lowering the temperature and adding the extractant after the reaction can avoid the influence of high temperature on the extractant and ensure the stability of the extraction process. Maintaining the temperature ≤5℃ during neutralization with a weak base can reduce heat release and avoid side reactions or product decomposition caused by temperature rise. Subsequently, adjusting the pH to strong alkalinity with an alkaline solution can ensure that residual acidic substances in the reaction system are completely neutralized, further optimizing the purity and stability of the product.

[0010] Preferably, in step (3), during vacuum distillation, the fraction with a boiling point of 115~125℃ at a pressure of 160Pa is collected.

[0011] Preferably, in step (3), after the reaction is completed, the mixture is cooled and a salt solution is added for salting-out separation, followed by extraction and salting-out washing. By employing the above methods, the risk of product decomposition at high temperatures can be reduced. At the same time, the salting-out effect is used to reduce the solubility of organic solvents in the aqueous phase, promote the separation of the organic and aqueous phases, help remove water-soluble impurities, and improve the purity of the target product in the organic phase.

[0012] Preferably, it includes the following steps: (1) Preparation of 5,6-diethyl-3-isobutylpyrazine-2-ol: Dissolve 133.3 g of 2-amino-4-methylpentanamide hydrochloride in 1600 mL of methanol and cool to -20±2℃. Add 85.6 g of 3,4-hexanedione and stir rapidly. Then add 90 g of 40% sodium hydroxide aqueous solution dropwise, keeping the reaction temperature ≤-10℃. After the addition is completed within 1 h, slowly raise the temperature to room temperature and stir the reaction for 12~36 h. After the reaction is completed, cool to 0±5℃ and add concentrated hydrochloric acid dropwise until the pH is 1~2, keeping the temperature ≤25℃. Then add sufficient sodium bicarbonate solution to neutralize the reaction solution to near neutral. Filter the reaction solution to obtain a filtrate. Wash the filtrate with sufficient saturated sodium chloride solution and separate the liquid. Remove methanol by rotary evaporation and dry with anhydrous sodium sulfate overnight to obtain a pale yellow liquid, which is 5,6-diethyl-3-isobutylpyrazine-2-ol. (2) Preparation of 2-chloro-5,6-diethyl-3-isobutylpyrazine: 41.7 g of 5,6-diethyl-3-isobutylpyrazine-2-ol was added to a three-necked flask containing 73.6 g of phosphorus oxychloride and heated to reflux. 50.0 g of phosphorus pentachloride was added in batches over 1 h. The mixture was heated to 170±20℃ and reacted for 1-3 h. After cooling to room temperature, the reactants were poured into a mixture of ice and methyl tert-butyl ether and neutralized with 25% ammonia water at a temperature ≤5℃. A 40% sodium hydroxide aqueous solution was then added dropwise to adjust the reaction mixture to a concentration of 12-13. The mixture was extracted with methyl tert-butyl ether, washed with sufficient saturated sodium chloride solution, and separated. The resulting organic phase was rotary evaporated to remove methyl tert-butyl ether and dried overnight with anhydrous sodium sulfate to obtain a pale yellow liquid, which was 2-chloro-5,6-diethyl-3-isobutylpyrazine. (3) Preparation of 2,3-diethyl-5-isobutyl-6-methoxypyrazine: 11.3 g of 2-chloro-5,6-diethyl-3-isobutylpyrazine and 25.6 g of methanol were added to a three-necked flask, followed by the addition of a methanol solution containing 13.5 g of sodium methoxide. The mixture was heated under reflux for 6–18 h, cooled, diluted with saturated sodium chloride solution, extracted with methyl tert-butyl ether, washed with sufficient saturated sodium chloride solution, and separated. The resulting organic phase was dried overnight with anhydrous sodium sulfate, the solvent was removed by rotary evaporation, and then the fraction with a boiling point of 115–125 °C at a pressure of 160 Pa was collected to obtain a colorless liquid, which is 2,3-diethyl-5-isobutyl-6-methoxypyrazine.

[0013] Thirdly, this invention discloses a multi-dimensional aroma base composition of spicy, green, and roasted aromas, employing the following technical solution: A spicy, green, roasted, multi-dimensional aroma base composition comprising the aforementioned characteristic compound of spicy, green, roasted, multi-dimensional aroma, 2,3-diethyl-5-isobutyl-6-methoxypyrazine.

[0014] Preferably, the product comprises the following components in parts by mass: 0.06 parts of 2,3-diethyl-5-isobutyl-6-methoxypyrazine, 30 parts of vetiver oil, 145 parts of cinnamon oil, 75 parts of perilla oil, 4 parts of abamectin oil, 30 parts of anethole, 12 parts of borneol, 64 parts of menthyl acetate, 15 parts of ethylnaphthalene ether, 25 parts of 4-terpinenol, and 599.94 parts of propylene glycol.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a multi-dimensional aroma compound with spicy, green, and roasted notes, and its preparation method. The compound exhibits significant multi-dimensional aroma characteristics of spiciness, greenness, and roasting, with an extremely low aroma threshold, long-lasting fragrance, and good stability. The preparation method is simple, uses mild conditions, and is easy to industrialize. The compound prepared by this method has broad application prospects in the fragrance and flavor industry, especially suitable for the formulation of high-end fragrances, significantly improving the realism and complexity of fragrances and meeting market demand for natural, long-lasting, and complex aromas. Furthermore, this compound can also be used to scent various daily chemical products such as detergents, air fresheners, and perfumes, as well as materials such as paper, plastics, and leather, offering significant economic and social benefits. Attached Figure Description

[0016] Figure 1 This is the reaction formula for the preparation of 5,6-diethyl-3-isobutylpyrazine-2-ol in step (1) of Example 1; Figure 2 This is the reaction formula for the preparation of 2-chloro-5,6-diethyl-3-isobutylpyrazine in step (2) of Example 1; Figure 3 This is the reaction formula for the preparation of 2,3-diethyl-5-isobutyl-6-methoxypyrazine in step (3) of Example 1; Figure 4 This is the gas chromatogram of 2,3-diethyl-5-isobutyl-6-methoxypyrazine in Example 1 of this invention. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1 This embodiment provides a compound with multidimensional aroma characteristics of fragrant green aroma and roasted aroma, and its preparation method includes the following steps: (1) Preparation of 5,6-diethyl-3-isobutylpyrazine-2-ol: Dissolve 133.3 g (0.80 mol) of 2-amino-4-methylpentanamide hydrochloride in 1600 mL of methanol and cool to -20°C. Add 85.6 g (0.75 mol) of 3,4-hexanedione and stir rapidly. Then add 90 g of a 40% sodium hydroxide aqueous solution (containing 36.0 g, 0.90 mol) dropwise, keeping the reaction temperature ≤ -10°C. After the addition is completed within 1 hour, slowly raise the temperature to room temperature and stir the reaction for 24 hours. h, after the reaction is completed, cool to 0℃ and add concentrated hydrochloric acid dropwise until the pH is 2, keeping the temperature ≤25℃ during the process. Then add sufficient sodium bicarbonate solution to neutralize the reaction solution to near neutrality. Filter the reaction solution to obtain the filtrate. Wash the filtrate with sufficient saturated sodium chloride solution and separate the liquid. Remove methanol by rotary evaporation of the obtained organic phase and dry it overnight with anhydrous sodium sulfate to obtain a pale yellow liquid, which is 5,6-diethyl-3-isobutylpyrazine-2-ol (49.5g). The reaction formula of step (1) is shown in the figure. Figure 1 .

[0019] (2) Preparation of 2-chloro-5,6-diethyl-3-isobutylpyrazine: 41.7 g (0.20 mol) of 5,6-diethyl-3-isobutylpyrazine-2-ol was added to a 500 mL dry three-necked flask containing 73.6 g (0.48 mol) of phosphorus oxychloride and heated to reflux. 50.0 g (0.24 mol) of phosphorus pentachloride was added in portions over 1 h. The mixture was heated to 170 °C and reacted for 2 h. After cooling to room temperature, the reactants were poured into a 1:1 mixture of ice and methyl tert-butyl ether and neutralized with 25% ammonia water at a temperature ≤5 °C during neutralization. The pH of the reaction mixture was adjusted to 13 by adding 40% sodium hydroxide solution dropwise. The mixture was then extracted with methyl tert-butyl ether (100...). The solution was then washed with a sufficient amount of saturated sodium chloride solution and separated. The organic phase was then removed by rotary evaporation of methyl tert-butyl ether and dried overnight with anhydrous sodium sulfate to obtain a pale yellow liquid, which was 2-chloro-5,6-diethyl-3-isobutylpyrazine (13.3 g). (3) Preparation of 2,3-diethyl-5-isobutyl-6-methoxypyrazine: 11.3 g (0.05 mol) of 2-chloro-5,6-diethyl-3-isobutylpyrazine and 25.6 g (0.80 mol) of methanol were added to a 250 mL dry three-necked flask. A methanol solution containing 13.5 g (0.25 mol) of sodium methoxide was then added. The mixture was heated under reflux for 12 h, cooled, and diluted with 50 mL of saturated sodium chloride solution. The mixture was extracted with methyl tert-butyl ether (50 mL × 3), washed with sufficient saturated sodium chloride solution, and separated. The resulting organic phase was dried overnight with anhydrous sodium sulfate. After removing the solvent by rotary evaporation, the mixture was distilled under reduced pressure. The fraction with a boiling point of 115–125 °C at a pressure of 160 Pa was collected, yielding a colorless liquid, 6.7 g (2,3-diethyl-5-isobutyl-6-methoxypyrazine), with a GC content of 98.9%. The 2,3-diethyl-5-isobutyl-6-methoxypyrazine obtained above has the following NMR spectral characteristics: 1 H NMR (400MHz, CDCl3) δ 3.95(s, 3H), 3.12-3.06(m, 4H), 2.50(d, J =7.2Hz, 2H), 1.87-1.72(m, 1H), 1.36-1.30(m, 6H), 0.89(d, J =3.4Hz, 6H); 13 C NMR (100MHz, CDCl3) δ 159.58, 149.05, 136.19, 134.61, 54.98, 37.92, 28.09, 28.00,27.95, 22.66, 22.62, 13.71, 13.60. The mass spectrometry analysis data of the 2,3-diethyl-5-isobutyl-6-methoxypyrazine prepared above are as follows: MS (ESI, m / z) 245.2 (M + Na + ); The theoretical calculation data for high-resolution electrospray ionization mass spectrometry are [C 13 H 22 Na N2O] + (M + Na + The actual measured value was 245.1630, but the actual measured value was 245.1628. The gas chromatography chromatogram of the 2,3-diethyl-5-isobutyl-6-methoxypyrazine prepared above is shown in the figure. Figure 1 .

[0020] Example 2 This embodiment provides a spicy, green, roasted, multi-dimensional aroma base composition. The formula is shown in Table 1. The raw materials listed in Table 1 are added to the reaction device in the indicated weight proportions. After the addition is complete, the mixture is stirred for 1 hour to obtain the spicy, green, roasted, multi-dimensional aroma base composition. Table 1. Fragrance Base Formula

[0021] Performance testing I. Aroma Evaluation of Compounds Twelve perfumers with over five years of experience were invited to evaluate the aroma of the 2,3-diethyl-5-isobutyl-6-methoxypyrazine compound prepared in Example 1 as follows: Twelve perfumers unanimously agreed that the compound possesses a spicy aroma, ten perfumers believed it has a green aroma, ten perfumers believed it has a toasty aroma, three perfumers believed it has an oily aroma, three perfumers believed it has an earthy aroma, and two perfumers believed it has a smoky quality. This indicates that 2,3-diethyl-5-isobutyl-6-methoxypyrazine possesses rich, multidimensional aroma characteristics, capable of accurately mimicking a variety of natural aromas, such as spicy, green, and toasty notes. This multidimensional aroma characteristic gives it a unique advantage in the fragrance and flavor industry, significantly enhancing the realism and complexity of fragrances.

[0022] II. Compound Aroma Detection Threshold Test Twelve perfumers with over five years of experience were invited to conduct detection threshold tests on 2,3-diethyl-5-isobutyl-6-methoxypyrazine according to the ISO 13301:2018 standard method. Its detection threshold in propylene glycol was 2.5 μg / L. This indicates that the aroma of 2,3-diethyl-5-isobutyl-6-methoxypyrazine is extremely sensitive, detectable even at very low concentrations. This characteristic makes it highly valuable in fragrances and flavorings, significantly enhancing aroma intensity and persistence even at low dosages. Pyrazine compounds typically have very low aroma thresholds because the pyrazine ring in their molecular structure can bind efficiently to olfactory receptors, generating a strong olfactory signal. 2,3-diethyl-5-isobutyl-6-methoxypyrazine, through optimized molecular structure, further lowers its aroma threshold, making it easily detectable even at low concentrations. This characteristic allows it to achieve significant aroma effects with lower dosage in fragrance formulations, reducing costs while improving aroma longevity.

[0023] III. Evaluation of Fragrance Retention by Compounds Prepare a 1% solution by mixing 0.1g of 2,3-diethyl-5-isobutyl-6-methoxypyrazine and 9.9g of propylene glycol. Take a scent test strip, dip it in a small amount of the solution, and place the test strip on a scent rack. Twelve perfumers with more than five years of experience smell the test strip every four hours. Record the lasting scent time when two or more perfumers cannot detect the scent on the test strip.

[0024] Fragrance retention tests showed that 2,3-diethyl-5-isobutyl-6-methoxypyrazine retained its fragrance for 56 hours. This result indicates that the compound possesses excellent fragrance retention properties, maintaining a stable aroma release over a longer period, significantly superior to many existing fragrance components. This gives it a significant advantage in fragrances and flavorings, meeting the market's demand for long-lasting aromas.

[0025] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A compound with multidimensional aroma characteristics of spicy, green, and roasted aromas, characterized in that, The compound is named 2,3-diethyl-5-isobutyl-6-methoxypyrazine, and its chemical structure is as follows: 。 2. A method for preparing the multi-dimensional aroma characteristic compound of spicy, green, and roasted aroma as described in claim 1, characterized in that, Includes the following steps: (1) 2-amino-4-methylpentanamide hydrochloride and 3,4-hexanedione were subjected to a condensation reaction in the presence of a solvent and under alkaline conditions. After the reaction was completed, the reaction was terminated by acid, neutralized by base, and washed by salting out. The organic phase was concentrated by rotary evaporation to obtain 5,6-diethyl-3-isobutylpyrazine-2-ol. (2) The 5,6-diethyl-3-isobutylpyrazine-2-ol obtained in step (1) is subjected to a halogenation reaction with a chlorinating agent. After the reaction is completed, the reaction solution is adjusted to strong alkalinity with an alkaline solution, and then extracted, salted out and washed. The organic phase is concentrated by rotary evaporation to obtain 2-chloro-5,6-diethyl-3-isobutylpyrazine. (3) The 2-chloro-5,6-diethyl-3-isobutylpyrazine obtained in step (2) was subjected to methoxylation reaction with sodium methoxide in methanol solution. After the reaction was completed, the organic phase was extracted, washed by salting out, concentrated by rotary evaporation, and the fraction was collected by vacuum distillation to obtain 2,3-diethyl-5-isobutyl-6-methoxypyrazine.

3. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, In step (1), before mixing 2-amino-4-methylpentanamide hydrochloride and 3,4-hexanedione, the system is cooled to -20±2℃. During the dropwise addition of alkali solution to the system, the reaction temperature is kept ≤10℃. After the dropwise addition is completed, the system is warmed back to room temperature and stirred for reaction. The pH of the acid termination is adjusted to 1~2.

4. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, In step (2), the chlorinating agent includes phosphorus oxychloride and phosphorus pentachloride. Phosphorus oxychloride is added first in the initial stage of the reaction, and then phosphorus pentachloride is added in batches for heating and reflux reaction.

5. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, In step (2), after the reaction is completed, the temperature is lowered and an extractant is added, and then a weak base is used for neutralization. During the neutralization, the temperature is ≤5℃, and then the pH is adjusted to 12~13 using an alkaline solution.

6. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, In step (3), during vacuum distillation, the fraction with a boiling point of 115~125℃ at a pressure of 160Pa is collected.

7. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, In step (3), after the reaction is completed, the mixture is cooled and a salt solution is added for salting-out separation, followed by extraction and salting-out washing.

8. The method for preparing the multi-dimensional aroma characteristic compounds of spicy, green, and roasted aroma according to claim 2, characterized in that, Includes the following steps: (1) Preparation of 5,6-diethyl-3-isobutylpyrazine-2-ol: Dissolve 133.3 g of 2-amino-4-methylpentanamide hydrochloride in 1600 mL of methanol and cool to -20±2℃. Add 85.6 g of 3,4-hexanedione and stir rapidly. Then add 90 g of 40% sodium hydroxide aqueous solution dropwise, keeping the reaction temperature ≤-10℃. After the addition is completed within 1 h, slowly raise the temperature to room temperature and stir the reaction for 12~36 h. After the reaction is completed, cool to 0±5℃ and add concentrated hydrochloric acid dropwise until the pH is 1~2, keeping the temperature ≤25℃. Then add sufficient sodium bicarbonate solution to neutralize the reaction solution to near neutral. Filter the reaction solution to obtain a filtrate. Wash the filtrate with sufficient saturated sodium chloride solution and separate the liquid. Remove methanol by rotary evaporation and dry with anhydrous sodium sulfate overnight to obtain a pale yellow liquid, which is 5,6-diethyl-3-isobutylpyrazine-2-ol. (2) Preparation of 2-chloro-5,6-diethyl-3-isobutylpyrazine: 41.7 g of 5,6-diethyl-3-isobutylpyrazine-2-ol was added to a three-necked flask containing 73.6 g of phosphorus oxychloride and heated to reflux. 50.0 g of phosphorus pentachloride was added in batches over 1 hour. The mixture was heated to 170±20℃ and reacted for 1-3 hours. After cooling to room temperature, the reactants were poured into a mixture of ice and methyl tert-butyl ether and neutralized with 25% ammonia water at a temperature ≤5℃. A 40% sodium hydroxide aqueous solution was then added dropwise to adjust the reaction mixture to a concentration of 12-13. The mixture was extracted with methyl tert-butyl ether, washed with sufficient saturated sodium chloride solution, and separated. The resulting organic phase was rotary evaporated to remove methyl tert-butyl ether and dried overnight with anhydrous sodium sulfate to obtain a pale yellow liquid, which was 2-chloro-5,6-diethyl-3-isobutylpyrazine. (3) Preparation of 2,3-diethyl-5-isobutyl-6-methoxypyrazine: 11.3 g of 2-chloro-5,6-diethyl-3-isobutylpyrazine and 25.6 g of methanol were added to a three-necked flask, followed by the addition of a methanol solution containing 13.5 g of sodium methoxide. The mixture was heated under reflux for 6–18 h, cooled, diluted with saturated sodium chloride solution, extracted with methyl tert-butyl ether, washed with sufficient saturated sodium chloride solution, and separated. The resulting organic phase was dried overnight with anhydrous sodium sulfate, the solvent was removed by rotary evaporation, and then the fraction with a boiling point of 115–125 °C at a pressure of 160 Pa was collected to obtain a colorless liquid, which is 2,3-diethyl-5-isobutyl-6-methoxypyrazine.

9. A spicy, green, roasted, multi-dimensional aroma base composition, characterized in that, Includes the multidimensional aroma characteristic compounds of spicy, green, roasted aroma as described in any one of claims 1-8.

10. The spicy, green, roasted, multi-dimensional aroma base composition according to claim 9, characterized in that, By mass parts, it includes the following components: 0.06 parts of 2,3-diethyl-5-isobutyl-6-methoxypyrazine, 30 parts of vetiver oil, 145 parts of cinnamon oil, 75 parts of perilla oil, 4 parts of abamectin oil, 30 parts of anethole, 12 parts of borneol, 64 parts of menthyl acetate, 15 parts of ethylnaphthalene ether, 25 parts of 4-terpinenol, and 599.94 parts of propylene glycol.

Images