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Watermelon ketone preparation method

A watermelon ketone and acetone technology, which is applied in the field of preparation of flavor and fragrance compounds, can solve the problems of poor chlorinated acetone activity, low phenolic hydroxyl condensation efficiency, increased by-products and the like, and achieves easy purification, easy reaction and reduced side reactions. Effect

Inactive Publication Date: 2018-06-15
王成宇
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of process reaction is relatively simple, but the disadvantages of this type of reaction are: firstly, the activity of chloroacetone is not good, and the condensation efficiency with phenolic hydroxyl is low, and it is not as good as -Br or -Ts to replace acetone; Interference by the ketone carbonyl group leads to increased by-products; in addition, 4-methylcatechol and 1,3-dichloroacetone are dual-reactive functional group compounds, adding in different order will lead to polymolecular (>2) condensation products happened

Method used

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Examples

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Effect test

Embodiment 1

[0025] Into a 1000 mL three-neck flask equipped with a thermometer, reflux condenser and constant pressure dropping funnel, add 210 mL of ethanol and 90 mL of water, 60 g of potassium hydroxide, and 5 g of potassium iodide, and place under vigorous magnetic force at 1000 r / min. Stir and slowly add 62 g of 4-methylcatechol and 130 g of ethanol solution of 1,3-dibromoacetone ketal, which are mixed evenly, dropwise under reflux, and continue to reflux for 4 h after the dropwise addition is complete. After the reaction is complete, stop stirring, cool, filter with suction, and recover the solvent by rotary evaporation. The remaining dark brown oil is dissolved in dichloromethane and washed with 5% sodium hydroxide solution, saturated sodium carbonate solution and saturated sodium chloride solution successively. until colorless, dried, spin-dried, and distilled under reduced pressure to obtain 97.9 g of a ketal product with a purity of 98%, with a yield of 90%.

Embodiment 2

[0027] In a 1000 mL three-necked flask equipped with a thermometer, a reflux condenser and a constant pressure dropping funnel, add 300 mL of acetone, 60 g of potassium hydroxide, and 5 g of ammonium iodide, and stir vigorously at 1000 r / min. , under reflux state, slowly add dropwise acetone solution of 62 g of 4-methylcatechol and 130 g of 1,3-dibromoacetone ethylene acetal, which are uniformly mixed, and continue to reflux for 4 h after the dropwise addition is completed. After the reaction is complete, stop stirring, cool, filter with suction, and recover the solvent by rotary evaporation. The remaining dark brown oil is dissolved in dichloromethane and washed with 5% sodium hydroxide solution, saturated sodium carbonate solution and saturated sodium chloride solution successively. until colorless, dried, spin-dried, and distilled under reduced pressure to obtain 99.1 g of a ketal product with a purity of 98%, with a yield of 91%.

Embodiment 3

[0029] Into a 1000 mL three-neck flask equipped with a thermometer, reflux condenser and constant pressure dropping funnel, add 210 mL of ethanol and 90 mL of water, 60 g of potassium hydroxide, and 5 g of potassium iodide, and place under vigorous magnetic force at 1000 r / min. Stir, slowly add dropwise the ethanol solution of 62 g of 4-methylcatechol and 221 g of 1,3-di-p-toluenesulfonate acetone ketal mixed uniformly under the reflux state, and continue to Reflux for 4 h. After the reaction is complete, stop stirring, cool, filter with suction, and recover the solvent by rotary evaporation. The remaining dark brown oil is dissolved in dichloromethane and washed with 5% sodium hydroxide solution, saturated sodium carbonate solution and saturated sodium chloride solution successively. until colorless, dried, spin-dried, and distilled under reduced pressure to obtain 102.3 g of a ketal product with a purity of 98%, and a yield of 94%.

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Abstract

The invention discloses a watermelon ketone preparation method which comprises the following steps: (1) under an alkali condition and in the presence of aids, heating 4-methyl-orthodioxybenzene and alcohol-protected ketalized 1,3-bisubstited acetone to 30-120 DEG C in a solvent, and performing a Williamson ether synthesis reaction so as to generate a corresponding ketal intermittent, wherein reaction materials are fed in the following sequence: firstly, adding the solvent, an alkali and aids, uniformly stirring, heating to a set temperature, slowly dropping 4-methyl-orthodioxybenzene and alcohol-protected ketalized 1,3-bisubstited acetone, and performing a reaction for 2-12 hours after dropping is competed; (2) performing a backflow reaction on the ketal intermittent obtained in the step (1) for a certain time under an acid condition, pouring into water to implement hydrolysis, extracting with ethyl ether, washing an organic phase with a sodium bicarbonate solution, drying sodium sulfate, evaporating off the solvent, and performing recrystallization, thereby obtaining watermelon ketone. The method disclosed by the invention is easy to control, simple to operate, good in environmentprotection, relatively high in yield and beneficial to industrialization.

Description

technical field [0001] The invention relates to a method for preparing flavor and fragrance compounds, in particular to a method for preparing watermelon ketone. Background technique [0002] The English name of watermelon ketone is Calone, that is, 7-methyl-3,4-dihydro-1,5-benzodioxepen-3-one, and its CAS number is 28940-11-6. Watermelon ketone not only has a fresh, fruit-like soft and sweet smell, but also has a marine, algal, and dreamlike feeling, and is widely used in the preparation and synthesis of flavors and fragrances. As a spice, watermelon ketone has been paid more and more attention by people, and has been widely used in the flavor, fragrance and cosmetics market. [0003] The structure of watermelon ketone is as follows: [0004] [0005] The preparation method of watermelon ketone mainly contains following several kinds: [0006] (1) In 1961, V. Rosnati et al. (Tetrahedron, 1962, 18, 289-298.) published the method of condensing catechol and 1,3-dichlorop...

Claims

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Application Information

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IPC IPC(8): C07D321/10
CPCC07D321/10
Inventor 王成宇
Owner 王成宇
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