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Method for producing .alpha.-alkoxy-.alpha.-trifluoromethyl-aryl acetic esters and -aryl acetic acids

  • US 6,162,943 A
  • Filed: 04/16/1999
  • Issued: 12/19/2000
  • Est. Priority Date: 10/22/1996
  • Status: Expired due to Fees
First Claim
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1. Process for the preparation of α

  • -alkoxy-α

    -trifluoromethyl-arylacetic esters of the formula (I) ##STR7## wherein R is selected from the group consisting of C1 -C6 -alkyl, C2 -C6 -alkenyl, C3 -C7 -cycloalkyl, C6 -C10 -aryl and C1 -C6 -halogenoalkyl,R'"'"' is selected from the group consisting of C1 -C4 -alkyl,X is selected from the group consisting of halogen, C1 -C4 -alkyl, C2 -C4 -alkenyl, C6 -C10 -aryl or C1 -C4 -alkoxy and nitro, andn is zero or an integer from 1 to 3;

    the process comprising the steps ofA) reacting (a) a keto ester of the formula (II) ##STR8## wherein R, X and n are as defined in formula (I), with (b) trifluoromethyl-trimethylsilane in the presence of (c) a solvent and (d) a fluoride that is at least slightly soluble in the reaction mixture as a catalyst to form a trimethyl silyl ether of the formula (III) ##STR9## wherein R, X and n are defined as in formula (I), B) reacting the trimethyl ether having formula (III) with an alkoxide, or an alcohol which has been rendered alkaline to give a salt of the compound of the formula (IV), ##STR10## wherein R, X and n are as defined in formula (I), and M+ is the ion of an alkali metal, andC) reacting the compound having the formula (IV) with an alkylating agent, to convert the O- M+ group into an OR'"'"' group.

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