- Preparation method of 5,5-dimethyl-2-cyanocyclopentanone
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The invention relates to a preparation method of 5,5-dimethyl-2-cyanocyclopentanone and a preparation method of a related intermediate 2,2-dimethyl-5-(4-chlorobenzyl)cyclopentanone and an application thereof to synthesis of a bactericide metconazole. Cholesteryl iso-butyrate, 1,3-dihalogenated propane, a cyanidation agent, p-chlorobenzyl chloride, and the like are used as main raw materials, multiple steps of reactions are used for preparation and separation, compared with a traditional process, the technique implementation is convenient and yield is high, and the methods have good industrial application prospects.
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Paragraph 0055; 0059; 0060
(2017/12/13)
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- Process for preparing 5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid
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An improved two-step process for preparing 5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid (gemfibrozil) which regularly affords gembibrozil in overall yields in excess of 80% comprises reacting an alkali metal salt of a lower alkyl ester of 2-methylpropanoic acid with 1,3-dibromopropane or 1-bromo-3-chloropropane in a polar aprotic solvent such as tetrahydrofuran, and then reacting the intermediate thus formed with an alkali metal salt of 2,5-dimethylphenol in a mixed toluene/dimethylsulfoxide solvent system.
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