Synthesis of watermelon ketone

Abstract

The invention discloses a method for synthesizing watermelon ketone. Under the protection of nitrogen, inorganic or organic base, PEG-400, potassium iodide, methanol, and 4-methyl pyrocatechol are added into a reactor and are heated to be between 65 and 70 DEG C, then 1,3-dichloroacetone is dripped into the mixture, and the mixture is subjected to reflux reaction under thermal insulation for 5 to 6 hours after the dripping is finished; a crude product is obtained through cooling and suction filtration, and the methanol is recovered; ethyl acetate is added into the crude product, a saturated saline solution is used to scrub to be neutral, and the ethyl acetate is recovered; and the reduced pressure distillation is performed, and a distillate is recrystallized by a mixed solvent of the methanol and n-hexane to obtain a white crystalline solid, namely the watermelon ketone, wherein the mass ratio of the 4-methyl pyrocatechol to the 1,3-dichloroacetone is 1 to 1, the mass ratio of the inorganic or organic base to the 4-methyl pyrocatechol is between 1 to 0.7 and 0.75, the mass ratio of the potassium iodide to the 4-methyl pyrocatechol is between 1 to 7.0 and 7.5, the mass ratio of the PEG-400 to the 4-methyl pyrocatechol is between 1 to 20 and 30, and the mass ratio of the methanol to the n-hexane in the mixed solvent is 1 to 2. The method adopts a one-pot method to synthesize a target product, and has the advantages of mild reaction conditions, convenient operation, and high product yield.

Description

technical field [0001] The present invention relates to a kind of synthesis method of fragrance compound, specifically a kind of synthesis method of watermelon ketone. Background technique [0002] Watermelon ketone, foreign trade name is Calone / Watermelon ketone, chemical name is 7-methyl-3,4-dihydro(2H)-1,5-benzodioxepen-3-one. [0003] In recent years, watermelon ketone has been widely used in the daily chemical products and cosmetics market. Because watermelon ketone itself has a fresh, fruit-like, soft and sweet smell, it also contains marine and algae, which gives people a dreamlike feeling. It can bring a new concept to the formulation of perfume, so it has become the first choice of many perfume experts at home and abroad. At present, there are only a few companies in the world producing watermelon ketone. my country’s demand for watermelon ketone mainly depends on imports. There are few reports on the synthesis method of watermelon ketone. In US Patent US3517031, 4...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of this synthetic route is that the Dickmann condensation requires the use of a strong base NaH as a reagent, the reaction conditions are harsh, the reaction yield is low, and it is difficult to industrialize production, so this synthetic route lacks broad application prospects

[0006] Canadian chemists use chloroacetonitrile as a starting material to prepare watermelon ketones. Although the yield has improved, NaH is still used as a reagent, which is not conducive to industrial production

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