| 摘要 |
NEW MATERIAL:A compound expressed by formula I (R is lower alkyl; X is halogen; Y is Cl, Br or I). EXAMPLE:Ethyl 2-(2,3-dichloro-4,5-difluorobenzoyl)acetate. USE:A synthetic intermediate for antimicrobial agents 8-halogeno-1-substituted-6- fluoro-1,4-dihydro-7-substituted-4-oxo-3-quinolinecarboxylic acids, etc. PREPARATION:An acid chloride expressed by formula II is condensed with a malonic acid ester in the presence of a magnesium alcoholate in an inert solvent, e.g. ether, etc., at -50-+50 deg.C to afford the aimed benzoylmalonic acid ester expressed by formula III (R and R' are lower alkyl), which is then decarboxylated in an aqueous solution of an acid to provide the aimed compound expressed by formula I.
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