A spiro-acetal-based flavor compound, a preparation method thereof, and a green woody amber base

Abstract

This invention relates to the field of fragrance and flavor technology, specifically to a spiroacetal fragrance compound, its preparation method, and a warm amber woody fragrance base. The spiroacetal fragrance compound has the following structural formula: [Insert structural formula here]. The spiroacetal fragrance compound obtained by this invention is 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane. This compound has a fresh green aroma with a warm amber woody note, and has significant application value and market prospects in the fragrance and flavor field, especially in fruit-scented fragrances and daily chemical products. The preparation method of this compound is simple, efficient, and suitable for industrial production. The warm amber woody fragrance base obtained by this invention, with the addition of the above-mentioned spiroacetal fragrance compound, has a prominent warm amber woody aroma, transitioning smoothly and naturally from a "green apple fruity aroma" to a "warm amber woody aroma," significantly improving the quality of the fragrance base.

Description

Technical Field

[0001] This invention relates to the field of fragrance and flavor technology, specifically to a spiroacetal fragrance compound and its preparation method, and a warm amber fragrance base. Background Technology

[0002] Spiroacetals are commonly used green and fruity components in fragrance formulations. Existing spiro[5.5]undecane spiroacetal fragrances (such as Magnolan and its alkyl-substituted derivatives) mainly contribute fresh top notes, but their aroma decays rapidly in the middle and base notes, lacking a natural extension to woody, amber, or warm base notes, and have a short lasting time. At the same time, no existing compound structures have been found to integrate green and amber woody notes in the same molecule. In addition, existing preparation methods suffer from low yields and purification difficulties. Therefore, developing a novel spiroacetal compound that combines green top notes with long-lasting amber woody notes, has a natural aroma transition, and whose preparation process is suitable for industrial production has become an urgent technical need to be addressed in this field. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a spiroacetal fragrance compound. This compound possesses a fresh, green aroma with a warm, amber-woody finish. It is particularly suitable for constructing a "green apple-amber-woody" transitional fragrance base, significantly enhancing the blending and longevity of the fragrance.

[0004] Another objective of this invention is to provide a method for preparing the above-mentioned spiroacetal fragrance compounds. The method is simple to prepare, and the obtained spiroacetal fragrance compounds have a fresh green aroma with a warm amber woody fragrance. The reaction conditions are mild, the operation is simple, the post-processing is simple, and the production efficiency is high, making it suitable for industrial production.

[0005] Another object of the present invention is to provide a warm amber woody fragrance base. This warm amber woody fragrance base contains spiroacetal fragrance compounds that provide a harmonious and natural transition from the "green fruity aroma of green apples" to the "warm amber woody aroma," resulting in a significant improvement in the fragrance base's aroma quality.

[0006] The objective of this invention is achieved through the following technical solution: a spiroacetal fragrance compound having the following structural formula: .

[0007] The spiroacetal fragrance compound can be named: 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

[0008] Another objective of this invention is achieved through the following technical solution: a method for preparing a spiroacetal fragrance compound, comprising the following steps: Step 1: Using 4-tert-butylcyclohexylformaldehyde and formaldehyde as raw materials, (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is prepared under alkaline conditions. The structural formula of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is shown below: ; Step 2: Using (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol and propionaldehyde obtained in Step 1 as raw materials, spiroacetal fragrance compounds are prepared under acid catalysis. The spiroacetal fragrance compound is 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

[0009] Furthermore, in step one, the preparation method of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol includes the following steps: S1-1. Dissolve 4-tert-butylcyclohexylformaldehyde in anhydrous ethanol and stir until completely dissolved to obtain feed solution A; mix formaldehyde aqueous solution, calcium hydroxide and deionized water to prepare a suspension alkaline solution to obtain feed solution B. S1-2. Feed solution A and feed solution B are simultaneously delivered to the microchannel reaction system via precision constant flow pumps at flow rates of 8-12 mL / min and 6-8 mL / min, respectively. The reaction is carried out at 80-90℃ and 0.1-0.5 MPa pressure, with a residence time of 25-35 min. S1-3. After the reaction solution flows out of the microchannel reactor, it is immediately mixed online with acid to neutralize the alkaline catalyst and terminate the reaction. The quenched reaction solution is then post-treated to obtain a crude product. The crude product is recrystallized from the ethyl acetate / methyl tert-butyl ether mixed solvent to obtain a white solid product, which is (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol.

[0010] Further, in step S1-1, 150-170g of 4-tert-butylcyclohexylformaldehyde is dissolved in 350-450 mL of anhydrous ethanol and stirred until completely dissolved to obtain feed solution A.

[0011] Furthermore, in step S1-1, 120-130 g of a 37% formaldehyde aqueous solution, 13-14 g of calcium hydroxide, and 150-250 mL of deionized water are mixed to prepare a suspended alkaline solution, which is used as feed solution B. The formaldehyde aqueous solution contains 1.5 mol of effective formaldehyde.

[0012] Furthermore, the preparation method of 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane includes the following steps: S2-1. A three-necked reaction flask equipped with a mechanical stirrer, a Dean-Stark water separator, and a reflux condenser is purged with nitrogen to replace the internal air of the system. The (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol, p-toluenesulfonic acid, and toluene prepared in step one are added to the reaction flask. Under nitrogen protection and stirring, the mixture is heated to 110-115°C and refluxed. Then, over 1-2 hours, propionaldehyde is slowly added dropwise to the reflux system through a constant pressure dropping funnel or syringe pump. After S2-2 and propionaldehyde are added, the system is refluxed at 110-115℃ for 10-14 hours. During this period, the generated water is continuously separated and removed using a Dean-Stark water separator. After the reaction solution is cooled to room temperature, solid sodium bicarbonate is added to neutralize the residual p-toluenesulfonic acid and the mixture is filtered. The filtrate is concentrated under reduced pressure, and the toluene solvent is evaporated to obtain the crude product. S2-3. The crude product is subjected to high vacuum distillation, and the fraction at 135-140℃ / 0.08 kPa is collected to obtain a colorless and transparent oily liquid product, which is 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

[0013] Further, in step S2-1, 150-250 g of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol, 3-4 g of p-toluenesulfonic acid, and 700-900 mL of toluene are added to the reaction flask. Under nitrogen protection and stirring, the mixture is heated to 110-115°C and refluxed. Then, within 1-2 hours, 70-75 g of propionaldehyde is slowly added dropwise to the reflux system through a constant pressure dropping funnel or syringe pump.

[0014] Another objective of the present invention is achieved through the following technical solution: a warm amber fragrance base, comprising the above-mentioned spiroacetal fragrance compounds.

[0015] Furthermore, the warm amber fragrance base of the green wood comprises the following raw materials: privet aldehyde, hexenol acetate, apple ester, neojasmaldehyde, cedrol, cashmereone, methyl dihydrojasmonic acid, lily aldehyde, phenethyl alcohol, peach aldehyde, galenamus, ambroxan, coumarin, tunamus, 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane and dipropylene glycol. Furthermore, the warm amber fragrance base of the green wood comprises the following raw materials in parts by weight: 3-8 parts of privet aldehyde, 2-6 parts of hexenol acetate, 2-4 parts of apple ester, 35-59 parts of neojasmine aldehyde, 40-50 parts of cedrol, 30-38 parts of cashmereone, 56-60 parts of dihydrojasmonic acid methyl ester, 26-30 parts of lily aldehyde, 22-28 parts of phenethyl alcohol, 12-18 parts of peach aldehyde, 80-84 parts of gallocha, 10-14 parts of ambergris furan, 15-19 parts of coumarin, 12-18 parts of tuna musk, 15-25 parts of 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane, and 550-650 parts of dipropylene glycol.

[0016] The beneficial effects of this invention are as follows: (1) The spiroacetal fragrance compound obtained in this invention is 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane. This compound has a fresh green aroma with a warm amber woody scent. This compound is particularly suitable for constructing a "green apple-amber woody" transitional fragrance base, which can significantly improve the blending and longevity of the fragrance. It has important application value and market prospects in the field of fragrances and flavors, especially in fruity fragrances and daily chemical products.

[0017] (2) The preparation method provided by the present invention is simple to prepare, and the obtained spiroacetal fragrance compounds have a fresh green aroma and a warm amber woody aroma. The reaction conditions are mild, the operation is simple, the post-processing is simple, and the production efficiency is high, making it suitable for industrial production.

[0018] (3) The warm amber fragrance base prepared by the present invention contains the spiroacetal fragrance compound. Compared with the fragrance base without the addition of the compound, it has a more prominent warm amber wood fragrance. The transition from "green apple fragrance" to "warm amber wood fragrance" is more harmonious and natural, and the fragrance base fragrance quality is significantly improved. Attached Figure Description

[0019] Figure 1 The gas chromatogram of 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane prepared in Example 1 is shown. Detailed Implementation

[0020] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0021] Example 1 This embodiment provides a spiroacetal fragrance compound having the following structural formula: .

[0022] The chemical name of the spiroacetal fragrance compound is: 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

[0023] The preparation method of the spiroacetal fragrance compound includes the following steps: Step 1: Using 4-tert-butylcyclohexylformaldehyde and formaldehyde as raw materials, (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is prepared under alkaline conditions. The chemical reaction formula for the preparation of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is as follows: 123 S1-1. Dissolve 168.0 g (1.0 mol) of 4-tert-butylcyclohexylformaldehyde in 400 mL of anhydrous ethanol and stir until completely dissolved to obtain feed solution A; mix 121.5 g of a 37% formaldehyde aqueous solution, 13.5 g of calcium hydroxide, and 200 mL of deionized water to prepare a suspension alkaline solution to obtain feed solution B; the formaldehyde aqueous solution contains 1.5 mol of effective formaldehyde; wherein, the structural formula of 4-tert-butylcyclohexylformaldehyde is shown in Formula 1, and the structural formula of formaldehyde is shown in Formula 2. S1-2. Feed solution A and feed solution B are simultaneously delivered to the microchannel reaction system via precision constant flow pumps at flow rates of 10 mL / min and 6.7 mL / min, respectively, and reacted at 85℃ and 0.3 MPa pressure for a residence time of 30 min. S1-3. After the reaction solution flows out of the microchannel reactor, it is immediately mixed online with acid to neutralize the alkaline catalyst and terminate the reaction. The quenched reaction solution is then post-treated to obtain a crude product. The crude product is recrystallized from the ethyl acetate / methyl tert-butyl ether mixed solvent to obtain 150.4 g of a white solid product. The white solid product is (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol, with a yield of 75.2% and an HPLC purity of 96.2%. The structural formula of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is shown in Formula 3.

[0025] Step 2: Using (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol and propionaldehyde obtained in Step 1 as raw materials, a spiroacetal fragrance compound is prepared under acid catalysis. The spiroacetal fragrance compound is 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane, wherein the chemical reaction formula of 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane is as follows:

[0026] 34.

[0027] S2-1. A three-necked reaction flask equipped with a mechanical stirrer, a Dean-Stark water separator, and a reflux condenser is purged with nitrogen to replace the internal air. 200.0 g (1.0 mol) of (4-tert-butyl-1-hydroxymethylcyclohexyl) methanol, 3.5 g of p-toluenesulfonic acid, and 800.0 mL of toluene are added to the reaction flask. Under nitrogen protection and stirring, the mixture is heated to 110-115 °C and refluxed. Subsequently, over 1.5 h, 72.5 g (1.25 mol) of propionaldehyde is slowly added dropwise to the reflux system using a constant-pressure dropping funnel or syringe pump. After S2-2 and propionaldehyde were added, the system was refluxed at 110-115℃ for 12 hours. During this period, the generated water was continuously separated and removed using a Dean-Stark water separator. After the reaction solution was cooled to room temperature, 5.0 g of solid sodium bicarbonate was added to neutralize the residual p-toluenesulfonic acid and the mixture was filtered. The filtrate was concentrated under reduced pressure, and the toluene solvent was evaporated to obtain the crude product. S2-3. The crude product was subjected to high-vacuum distillation, and the fraction collected at 135-140℃ / 0.08 kPa was used to obtain 185.5 g of a colorless and transparent oily liquid product. The colorless and transparent oily liquid product was 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane, with a yield of 77.3% and a purity of 97.5% as determined by gas chromatography (GC). The structural formula of 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane is shown in Formula 4.

[0028] The 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane prepared in this example has the following NMR spectral characteristics: ¹H NMR (400 MHz, CDCl3) δ: 0.93 (s, 9H), 0.97 (t, J = 7.5 Hz, 3H), 1.36–1.45 (m, 9H), 1.62 (m, 2H), 3.70 (m, 4H), 4.67 (m, 1H). ¹³C NMR (100 MHz, CDCl3) δ: 4.5, 22.2 (2C), 26.3 (2C), 27.3 (3C), 29.0, 31.7, 33.8, 47.7, 74.4 (2C), 106.4. The mass spectrometry analysis data are as follows: MS (ESI, m / z) 263.2 (M + Na + The theoretical calculation data for high-resolution electrospray ionization mass spectrometry are [C 15 H 28 NaO2] + (M + Na+ The actual measured value was 263.1986, not 263.1992. Example 2 Aroma rating and longevity tests were performed on 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane prepared in Example 1. The test results are as follows: (1) Aroma evaluation: Nine perfumers with more than 5 years of work experience made the following evaluation of the aroma of the compound: The nine perfumers unanimously agreed that in addition to the fresh green aroma, the compound also has a warm amber woody aroma.

[0029] (2) Scent retention test: Take one scent test strip, dip it in 0.1 g of 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane, place the test strip on the scent rack, and have 3 perfumers smell it once every 2 hours. When more than 2 perfumers cannot perceive the scent of the scent test strip, record the scent retention time.

[0030] Scent retention tests showed that the green scent retention time of 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane was 16 hours, and the scent retention time of amberwood was 48 hours.

[0031] Example 3 This embodiment provides a warm amber wood fragrance base, which comprises the following raw materials in parts by weight: 5 parts of privet aldehyde, 4 parts of hexenol acetate, 3 parts of apple ester, 37 parts of neojasmine aldehyde, 45 parts of cedrol, 34 parts of cashmereone, 58 parts of dihydrojasmonic acid methyl ester, 28 parts of lily aldehyde, 25 parts of phenethyl alcohol, 15 parts of peach aldehyde, 82 parts of galena, 12 parts of ambergris furan, 17 parts of coumarin, 15 parts of tuna musk, 20 parts of 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane, and 600 parts of dipropylene glycol, which is fragrance base A in Table 1.

[0032] Unlike the warm amber fragrance base (A fragrance base), the A fragrance base replaces the target product of this invention, 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane, with an equal amount of dipropylene glycol. That is, the A fragrance base includes the following raw materials in parts by weight: 5 parts of privet aldehyde, 4 parts of hexenol acetate, 3 parts of apple ester, 37 parts of neojasmine aldehyde, 45 parts of cedrol, 34 parts of cashmereone, 58 parts of dihydrojasmone methyl ester, 28 parts of lily aldehyde, 25 parts of phenethyl alcohol, 15 parts of peach aldehyde, 82 parts of galore musk, 12 parts of ambroxan, 17 parts of coumarin, 15 parts of tuna musk, and 620 parts of dipropylene glycol.

[0033] The formulations of the warm amber fragrance base (B base) and the A base are shown in Table 1 below: Table 1

[0034] Prepare fragrance base A and fragrance base B according to the formula in the table above. Add 20 parts of the target product of this invention, 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane, to fragrance base A. After evaluating the fragrance base, seven perfumers with more than five years of experience made the following evaluations: The seven perfumers unanimously agreed that fragrance base A has a more prominent warm amber woody aroma than fragrance base B. The transition from "green apple fruity aroma" to "warm amber woody aroma" is more harmonious and natural, and the quality of the fragrance base aroma is significantly improved.

[0035] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A spiroacetal fragrance compound, characterized in that: It has the following structural formula: 。 2. A method for preparing a spiroacetal fragrance compound as described in claim 1, characterized in that: Includes the following steps: Step 1: Using 4-tert-butylcyclohexylformaldehyde and formaldehyde as raw materials, (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is prepared under alkaline conditions. The structural formula of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol is shown below: ； Step 2: Using (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol and propionaldehyde obtained in Step 1 as raw materials, spiroacetal fragrance compounds are prepared under acid catalysis. The spiroacetal fragrance compound is 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

3. The method for preparing spiroacetal fragrance compounds according to claim 2, characterized in that: In step one, the preparation method of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol includes the following steps: S1-1. Dissolve 4-tert-butylcyclohexylformaldehyde in anhydrous ethanol and stir until completely dissolved to obtain feed solution A; mix formaldehyde aqueous solution, calcium hydroxide and deionized water to prepare a suspension alkaline solution to obtain feed solution B. S1-2. Feed solution A and feed solution B are simultaneously delivered to the microchannel reaction system via precision constant flow pumps at flow rates of 8-12 mL / min and 6-8 mL / min, respectively. The reaction is carried out at 80-90℃ and 0.1-0.5 MPa pressure, with a residence time of 25-35 min. S1-3. After the reaction solution flows out of the microchannel reactor, it is immediately mixed online with acid to neutralize the alkaline catalyst and terminate the reaction. The quenched reaction solution is then post-treated to obtain a crude product. The crude product is recrystallized from the ethyl acetate / methyl tert-butyl ether mixed solvent to obtain a white solid product, which is (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol.

4. The method for preparing spiroacetal fragrance compounds according to claim 3, characterized in that: In step S1-1, 150-170g of 4-tert-butylcyclohexylformaldehyde is dissolved in 350-450 mL of anhydrous ethanol and stirred until completely dissolved to obtain feed solution A.

5. The method for preparing spiroacetal fragrance compounds according to claim 3, characterized in that: In step S1-1, 120-130 g of a 37% formaldehyde aqueous solution, 13-14 g of calcium hydroxide, and 150-250 mL of deionized water are mixed to prepare a suspended alkaline solution, which is used as feed solution B. The formaldehyde aqueous solution contains 1.5 mol of effective formaldehyde.

6. The method for preparing spiroacetal fragrance compounds according to claim 2, characterized in that: In step two, the preparation method of 3-ethyl-9-tert-butyl-2,4-dioxaspiro[5.5]undecane includes the following steps: S2-1. A three-necked reaction flask equipped with a mechanical stirrer, a Dean-Stark water separator, and a reflux condenser is purged with nitrogen to replace the internal air of the system. The (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol, p-toluenesulfonic acid, and toluene prepared in step one are added to the reaction flask. Under nitrogen protection and stirring, the mixture is heated to 110-115°C and refluxed. Then, over 1-2 hours, propionaldehyde is slowly added dropwise to the reflux system through a constant pressure dropping funnel or syringe pump. After S2-2 and propionaldehyde are added, the system is refluxed at 110-115℃ for 10-14 hours. During this period, the generated water is continuously separated and removed using a Dean-Stark water separator. After the reaction solution is cooled to room temperature, solid sodium bicarbonate is added to neutralize the residual p-toluenesulfonic acid and the mixture is filtered. The filtrate is concentrated under reduced pressure, and the toluene solvent is evaporated to obtain the crude product. S2-3. The crude product is subjected to high vacuum distillation, and the fraction at 135-140℃ / 0.08 kPa is collected to obtain a colorless and transparent oily liquid product, which is 3-ethyl-9-tert-butyl-2,4-dioxane[5.5]undecane.

7. The method for preparing spiroacetal fragrance compounds according to claim 6, characterized in that: In step S2-1, 150-250 g of (4-tert-butyl-1-hydroxymethylcyclohexyl)methanol, 3-4 g of p-toluenesulfonic acid, and 700-900 mL of toluene are added to the reaction flask. Under nitrogen protection and stirring, the mixture is heated to 110-115°C and refluxed. Then, within 1-2 hours, 70-75 g of propionaldehyde is slowly added dropwise to the reflux system through a constant pressure dropping funnel or syringe pump.

8. A warm amber woody fragrance base, characterized in that: Includes the spiroacetal fragrance compounds as described in claim 1.

9. The woody warm amber fragrance base according to claim 8, characterized in that: The ingredients include the following: privet aldehyde, hexenol acetate, apple ester, neojasmaldehyde, cedrol, cashmereone, dihydrojasmonic acid methyl ester, lily aldehyde, phenylethanol, peach aldehyde, galaxyl musk, ambroxan, coumarin, tuna musk, 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane and dipropylene glycol.

10. The woody warm amber fragrance base according to claim 8, characterized in that: The raw materials include the following parts by weight: 3-8 parts of privet aldehyde, 2-6 parts of hexenol acetate, 2-4 parts of apple ester, 35-59 parts of neojasmine aldehyde, 40-50 parts of cedrol, 30-38 parts of cashmereone, 56-60 parts of dihydrojasmonic acid methyl ester, 26-30 parts of lily aldehyde, 22-28 parts of phenethyl alcohol, 12-18 parts of peach aldehyde, 80-84 parts of galena, 10-14 parts of ambroxan, 15-19 parts of coumarin, 12-18 parts of tuna musk, 15-25 parts of 9-tert-butyl-3-ethyl-2,4-dioxane[5.5]undecane, and 550-650 parts of dipropylene glycol.

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