2, 6-di-tert-butyl-4-(2-methoxyphenylmethylene)-2, 5-cyclohexadiene-1-one and preparation method thereof

Abstract

The invention discloses 2, 6-di-tert-butyl-4-(2-methoxyphenylmethylene)-2, 5-cyclohexadiene-1-one. A preparation method of 2, 6-di-tert-butyl-4-(2-methoxyphenylmethylene)-2, 5-cyclohexadiene-1-one comprises the following steps: 1) preparing a Mannich base: heating 2, 6-di-tert-butylphenol and ortho-anisaldehyde to reflux temperature of 100-160 DEG C, then performing heat preservation and dropwise adding secondary amine; and further performing reflux reaction on 2, 6-di-tert-butylphenol and ortho-anisaldehyde under the catalytic action of secondary amine in solvent-free conditions; 2) removing secondary amine in the Mannich base: performing reduced pressure distillation on a reaction solution obtained in the step 1) to remove secondary amine in the Mannich base so as to obtain a crude product; and 3) recrystallizing the crude product: performing recrystallization on the crude product obtained in the step 2) by adopting a hot melting and cold separation method to obtain 2, 6-di-tert-butyl-4-(2-methoxyphenylmethylene)-2, 5-cyclohexadiene-1-one.

Description

technical field [0001] The present invention relates to a kind of synthetic method of organic compound, especially 2,6-di-tert-butyl-4-(2-methoxybenzylidene)-2,5-cyclohexadien-1-one (QM -ph-o-OMe) preparation method. Background technique [0002] 2,6-Di-tert-butyl-4-(2-methoxybenzylidene)-2,5-cyclohexadien-1-one (QM-ph-o-OMe), whose molecular formula is C 22 h 28 o 2 , whose chemical formula is shown in formula S-1; it is a p-methylene quinone compound. [0003] [0004] At present, there is no literature report about QM-ph-o-OMe and its synthesis method. [0005] By consulting the literature, we found that the preparation methods of its analogue 2,6-di-tert-butyl-4-benzylidene-2,5-cyclohexadien-1-one (QM-ph) mainly include the following : [0006] 1), methylene oxidation method: Mueller E. et al. reported a method of using 2,6-di-tert-butylphenol and benzyl alcohol as raw materials, first adding dehydration and then oxidation to prepare QM-ph, such as formula S -2...

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Problems solved by technology

[0012] The synthesis of QM-ph by methylene oxidation requires the use of a highly toxic solvent, benzene, and an oxidant, potassium ferricyanide, which causes great environmental pollution.

Synthesis of QM-ph by phenyllithium method or Grignard reagent method, the raw materials are phenyllithium and 3,5-di-tert-butyl-4-hydroxybenzaldehyde, the price is more expensive; the reaction needs to be carried out in anhydrous or anhydrous and oxygen-free environment It is carried out under high conditions and has high requirements for operation and equipment, so it is not suitable for industrial production

The currently reported Mannich method has a yield of up to 86.1%. However, after the Mannich base is formed, the Mannich base is deaminated to obtain the final product QM-ph. This process requires the use of xylene, HCl, acetic anhydride, etc. A large amount of chemicals, large emissions and serious pollution; and the amount of secondary amine exceeds the equimolar amount of 2,6-di-tert-butylphenol, which will lead to an increase in cost

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