Synthesis method of watermelon ketone

Abstract

The invention discloses a synthesis method of watermelon ketone. Under protection of nitrogen, a sodium carbonate solution and 4-methylcatechol are added into a reactor, temperature is controlled at 60-80 DEG C for 1-2 hours, methylbenzene is added to completely bring out water at normal pressure, organic alkali and iodinated amine are added, then a mixed solution of 1- dichloroacetone, 3-dichloroacetone and butanone is dropwise added at the temperature of 60-80 DEG C, heat preservation reaction is carried out for 3-5 hours after dripping, crude products are obtained after cooling and suction filtration, methylbenzene is recycled, a sodium sulfate solution is used for washing until the crude products are neutral, decompression distillation is carried out, distillate is recrystallized through a mixed solvent of acetone and normal hexane, and white crystal solid watermelon ketone is obtained. The synthesis method is adopted for synthesizing target products, reaction conditions are easy to control, operation is simple, yield coefficient is high, production cost is low, and reaction is safe and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for synthesizing watermelon ketone. Background technique [0002] Watermelon ketone is called Calone / Watermelon ketone abroad, and its chemical name is 7-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one. [0003] With the development of the fragrance industry, watermelon ketone is widely used. Due to the characteristics of watermelon ketone itself, it is a new concept for the preparation of perfume, so it has become a new choice for domestic and foreign fragrance experts. China's demand for watermelon ketone mainly depends on imports. The synthetic method about watermelon ketone mainly contains following several. For example: [0004] U.S. reports use 4-methylcatechol and methyl bromoacetate to condense into the intermediate of dicarboxylates, then under the effect of strong base, by Dieckmann condensation, obtain the compound of 2-methoxyformyl, then Then hyd...

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Problems solved by technology

[0006] An Italian chemist used 4-methylcatechol and l,3-dichloropropanol to condense into intermediate benzocycloheptanol, and then oxidized to obtain watermelon ketone, but the yield was 4%

[0007] In addition, 4-methylcatechol and dichloroacetone are used as raw materials, 4-methylcatechol is condensed, and watermelon ketone can also be obtained through ring formation and rearrangement. Although the reaction steps are simple, watermelon ketone can be synthesized in one step , but the yield can only reach 50%

[0008] In summary, the methods disclosed in the U.S. and Canada all require the use of a strong base NaH as a reagent, the reaction conditions are harsh, the reaction yield is low, and it is not suitable for industrial production; the method disclosed in Italy has too low yield and no use value; Catechol and dichloroacetone are used as raw materials to obtain watermelon ketone through ring formation and rearrangement. Although this method can be used in production, the yield is not very high (only up to 50%)

[0009] The applicant’s previous patent application, the application number is 200810244583.7, discloses a synthetic method of watermelon ketone, the synthetic method adopts a one-pot method, and the biggest defect is that the yield is also very low (less than 50%)

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