Process for the preparation of alpha-ketocarbonic acid esters

摘要

Process for the preparation of E-oxime ethers of phenylglyoxylic acid esters of the general formula I …… in which the variables have the following meanings: … …  the substituents X and Y are selected from a group comprising halogen, C1-C4-alkyl, C1-C4-alkoxy or trifluoromethyl; …  m is an integer from 0 to 4; …  n is an integer from 0 to 3,… and in which … …  a) a phenol of the general formula II …… is converted into the phenolate, …  b) the latter is mixed with a lactone of the general formula III …… …  c) the molten mixture is reacted, and …  d) the resulting 2-phenoxymethylbenzoic acid of the general formula IV …… is converted, via the acid chloride, into the benzoyl cyanide and this is converted into the corresponding alpha-keto acid, which is converted into the compound I. … … Alternatively, the compound IV can be converted, via the ester, into the beta-keto sulphoxide, which is reacted to give the beta-keto ester, which is subsequently converted into the compound I.