Method for synthesizing jasmine lactone through photocatalytic reaction

Abstract

The invention discloses a method for synthesizing jasmine lactone through photocatalytic reaction, and belongs to the field of fine chemicals. The synthesis method comprises the following steps: taking (E)-1, 6-octadiene-3-ketone-2 and iodoacetic acid as raw materials, carrying out photocatalytic reaction to obtain (E)-5-oxo-8-decenoic acid, then reacting with sodium borohydride to obtain (E)-5-hydroxy-8-decenoic acid, and carrying out esterification reaction on a crude product under the catalysis of acid without separation to obtain jasmonlactone. The method for obtaining the jasmine lactone has the advantages of easiness in synthesis of raw materials, mild reaction conditions, low cost and few steps, shows the superiority and simplicity of the synthesis method, and provides a simple way for preparation of the compounds.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine chemicals, and particularly relates to a method for synthesizing jasminoid by a photocatalytic reaction. BACKGROUND

[0002] Jasminoid (1), chemical name: tetrahydro-6-(3-pentenyl)-2H-pyran-2-one, English name: 6-(3-pentenyl)-tetrahydro-2H-pyran-2-one, CAS: 32764-98-0, is a colorless to light yellow liquid with a creamy, milk, fruit odor. Its boiling point is about 281.5℃ (95-100℃ / 133.3Pa), the relative density is 0.995-1.005, it is insoluble in water and soluble in organic solvents such as ethanol. Jasminoid has a jasmine petal-like aroma with a peach, almond and coconut milk-like aroma, and is used for blending apricot, peach, coconut, tropical fruit, dairy product and other edible flavors. Its structural formula is as follows:

[0003]

[0004] The efficient and simple synthesis of jasminoid has been widely valued, but the existing synthesis methods are very limited, mainly including the following two routes:

[0005] (1) (E)-1-bromo-2-butene and cyclohexanone are reacted as the main steps (Rosenmund, Karl Wilhehm et al, Chemische Berichte, 1961, 94, 2401-2405), but the steps are many and the yield is low;

[0006] (2) (E)-2-(3-penten-1-yl)cyclopentanone is used as a raw material, and Baeyer-Villiger reaction is used to convert it into the product (Fink, Michael J et al, Bioorganic & Medicinal Chemistry Letters, 2011, 21(20), 6135-6138), and the disadvantages are low yield and great difficulty in synthesis of the raw material.

[0007] The above two reaction routes cannot meet the needs of industrialization, and limit the expansion of the synthesis scale of jasminoid. Developing a new type of chemical synthesis method to solve the problems of many steps and low yield has important significance for expanding the source of jasminoid and thus expanding its application range. SUMMARY

[0008] In order to solve the problems of the prior art, the application provides a method for synthesizing jasminoid by a photocatalytic reaction.

[0009] The method for synthesizing jasminoid by a photocatalytic reaction is shown by a reaction equation as follows:

[0010]

[0011] The method for synthesizing jasminoid by a photocatalytic reaction has the advantages of easy synthesis of raw materials, mild reaction conditions, low cost and few steps, which shows the superiority and simplicity of the synthesis method.

[0012] The technical scheme of the application is: a method for synthesizing jasminoid by a photocatalytic reaction, comprising the following steps: taking (E)-1,6-octadiene-3-ketone 2 and iodoacetic acid 3 as raw materials, obtaining (E)-5-oxo-8-decenoic acid 4 by a photocatalytic reaction, then reacting with sodium borohydride to obtain (E)-5-hydroxy-8-decenoic acid 5, without separation, and then performing esterification of the crude product under acid catalysis to obtain jasminoid 1.

[0013] Further, in the above technical scheme, the photocatalyst is selected from 9-cymene-10-phenylacridine-10-tetrafluoroborate, tris(2,2'-bipyridine)ruthenium(II) (hydrochloride), tris(2-phenylpyridine)iridium(III) or bis[2-(2,4-difluorophenyl)-5-methylpyridine][2,2'-bi(4-tert-butylpyridine)]iridium(III) (hexafluorophosphate).

[0014] Further, in the above technical scheme, the molar ratio of (E)-1,6-octadiene-3-ketone 2, iodoacetic acid 3 and the photocatalyst is 1:1-3:0.05-0.2.

[0015] Further, in the above technical scheme, the organic solvent is selected from one or more of acetonitrile, chloroform, benzene, dimethyl sulfoxide, ethyl acetate and dichloromethane.

[0016] Further, in the above technical scheme, the photocatalytic reaction temperature of (E)-1,6-octadiene-3-ketone 2 and iodoacetic acid 3 is 25-60°C, and the reaction time is 1-24h.

[0017] Further, in the above technical solution, the visible light is light generated by an LED lamp, the LED lamp has a power of 5-50 W, and the LED lamp is 2-10 cm away from the reaction container during the reaction.

[0018] Further, in the above technical solution, the synthesis of the jasmine lactone 1 from the (E)-5-oxo-8-decenoic acid 4 is performed as follows: the intermediate 4 is reacted with sodium borohydride in water to convert the carbonyl group at the 5 position into a hydroxyl group, and after conventional post-treatment such as neutralization, extraction, and drying, the intermediate 5 is obtained, which does not need to be separated; the intermediate 5 is reacted under the catalysis of p-toluenesulfonic acid, water generated in the reaction is distilled off, and after the reaction is completed, the target product, the jasmine lactone 1, is obtained by distillation.

[0019] The jasmine lactone obtained by using the method has the advantages of easy synthesis of raw materials, mild reaction conditions, low cost, and few steps, which indicates the superiority and simplicity of the synthesis method. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The (E)-5-oxo-8-decenoic acid product obtained in Example 1 is analyzed by 1 HNMR spectroscopy.

[0021] Figure 2 The (E)-5-oxo-8-decenoic acid product obtained in Example 1 is analyzed by 13 CNMR spectroscopy.

[0022] Figure 3 The jasmine lactone product obtained in Example 3 is analyzed by 1 HNMR spectroscopy.

[0023] Figure 4 The jasmine lactone product obtained in Example 3 is analyzed by 13 CNMR spectroscopy. DETAILED DESCRIPTION

[0024] The application will be described in detail below with reference to the examples.

[0025] Example 1:

[0026] (E)-1,6-octadien-3-one 2 (0.124 g, 1 mmol), iodoacetic acid 3 (0.372 g, 2 mmol), tris(2-phenylpyridine)iridium(III) (0.0327 g, 0.05 mmol), tributylamine (0.475 mL, 2 mmol), Hans ester (2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester) (0.506 g, 2 mmol) were added to acetonitrile (10 mL), 5 W visible white light was opened, stirred, irradiated at room temperature for 12 h, TLC showed that the reaction was complete, the reaction solution was concentrated under reduced pressure, column chromatography was separated to obtain 0.134 g of (E)-5-oxo-8-decenoic acid 4, yield 73%. White solid, m.p. 54-56 °C. 1 H NMR (CDCI3, 400 MHz) δ 5.49-5.34 (m, 2H), 2.51-2.43 (m, 4H), 2.38 (t, J = 7.2 Hz, 2H), 2.25 (q, J = 6.8 Hz, 2H), 1.93-1.86 (m, 2H), 1.63 (d, J = 4.8 Hz, 3H); 13 C NMR (CDCI3, 100 MHz) δ 209.8, 179.1, 129.4, 126.1, 42.7, 41.4, 33.0, 26.8, 18.5.

[0027] Example 2:

[0028] Using 1 mmol of (E)-1,6-octadien-3-one 2 as raw material, other reaction conditions were changed, and the reaction results were as follows:

[0029]

[0030]

[0031] Example 3:

[0032] The intermediate 4 (0.184 g, 1 mmol) was added to water (10 mL), and sodium borohydride (0.0016 g, 0.4 mmol) was slowly added, and the temperature was controlled below 40 °C. After adding, it was stirred for 30 minutes. After the reaction was completed, the temperature was controlled below 35 °C, and concentrated hydrochloric acid was added dropwise to adjust the pH value to 4-5. The organic phase was separated, the aqueous phase was extracted twice with ethyl acetate (5 mL), the combined organic phase was dried with anhydrous sodium sulfate (0.2 g) for 1 h, and then filtered and concentrated to obtain the intermediate 5. Without separation, p-toluenesulfonic acid (0.0009 g, 0.005 mmol) was added, and the internal temperature was maintained at 80-100 °C. The water pump was used for reduced pressure reaction for 3 h. After the reaction was completed, the temperature was continuously increased to 140-145 °C, and the oil pump was used for reduced pressure distillation to obtain 0.114 g of jasmine lactone, with a yield of 68%, which was a colorless oil.1 HNMR (CDC13, 400 MHz) δ 5.52-5.31 (m, 2H), 4.30-2.24 (m, 1H), 2.61-2.52 (m, 1H), 2.48-2.37 (m, 1H), 2.23-2.05 (m, 2H), 1.93-1.71 (m, 4H), 1.64 (d, J = 8 Hz, 3H), 1.58-1.45 (m, 2H); 13 CNMR (CDC13, 100 MHz) δ 172.0, 129.9, 126.1, 79.9, 35.6, 29.5, 27.9, 27.8, 18.5.

[0033] The foregoing is considered as illustrative only of the principles of the application and the application is to be regarded in all respects as only as illustrative and not restrictive. Changes and modifications can be made in the application without departing from the spirit and scope thereof. The scope of the application is indicated by the following claims and all equivalents thereof.

Claims

1. A method for synthesizing a jasminoid lactone by a photocatalytic reaction, characterized by, The synthesis was carried out by the following reaction equation: The synthesis method comprises the following steps: taking (E)-1,6-octadiene-3-ketone 2 and iodoacetic acid 3 as raw materials, (E)-5-oxo-8-decenoic acid 4 is obtained by photocatalytic reaction, then reacts with sodium borohydride to obtain (E)-5-hydroxy-8-decenoic acid 5, without separation, the crude product is subjected to esterification reaction under acid catalysis to obtain jasmine lactone 1.

2. The method for synthesizing the jasminoid lactone through the photocatalytic reaction according to claim 1, characterized in that: The photocatalyst is selected from 9-cymene-10-phenylacridine-10-tetrafluoroborate, tris(2,2'-bipyridine)ruthenium(II) (hydrochloride), tris(2-phenylpyridine)iridium(III) or bis[2-(2,4-difluorophenyl)-5-methylpyridine][2,2'-bi(4-tert-butylpyridine)]iridium(III) (hexafluorophosphate).

3. The method for synthesizing the jasmolin by the photocatalytic reaction according to claim 1, characterized in that: The molar ratio of (E)-1,6-octadiene-3-ketone 2, iodoacetic acid 3 and photocatalyst is 1:1-3:0.05-0.

2.

4. The method for synthesizing the jasmolin by the photocatalytic reaction according to claim 1, characterized in that: The organic solvent is selected from one or more of acetonitrile, chloroform, benzene, dimethyl sulfoxide, ethyl acetate, dichloromethane.

5. The method for synthesizing the jasmolin by the photocatalytic reaction according to claim 1, characterized in that: The photocatalytic reaction temperature of (E)-1,6-octadiene-3-ketone 2 and iodoacetic acid 3 is 25-60℃, and the reaction time is 1-24h. 6.The method for synthesizing the jasmolin by the photocatalytic reaction according to any one of claims 1-5, characterized in that: The visible light is light generated by an LED lamp, the power of the LED lamp is 5-50W, and the distance between the LED lamp and the reaction container is 2-10cm during the reaction. 7.The method of claim 1, wherein the synthesis of the jasmolactone by the photocatalytic reaction is characterized by, The operation of synthesizing jasmine lactone 1 from (E)-5-oxo-8-decenoic acid 4 is as follows: taking water as the solvent, the intermediate 4 reacts with sodium borohydride to convert the 5-position carbonyl group into a hydroxyl group, and after neutralization, extraction, drying and other conventional post-treatments, the intermediate 5 is obtained, without separation, the intermediate 5 is reacted under the catalysis of p-toluenesulfonic acid, the water generated in the reaction is distilled off, after the reaction is completed, the target product jasmine lactone 1 is obtained by distillation.

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