| 摘要 |
PROBLEM TO BE SOLVED: To provide a new compound consisting of a specific substituted styrene derivative and useful as an intermediate for a substituted propionic acid having antiinflammatory, analgesic and antipyretic actions, etc. SOLUTION: The objective compound is expressed by formula I (R is a <=4C alkyl), e.g. 1-(4'-vinylvenzyl)-2-oxocyclopentanecarboxylic acid methyl ester. The compound of formula I can be produced by the benzylation reaction of a 2-oxocyclopentanecarboxylic acid ester of formula II with 4- chloromethylstyrene. The reaction is carried out in the presence of a base such as sodium hydride. N,N-dimethylformamide, etc., can be used as the reaction solvent. Loxoprofen can be produced by dehydrobrominating 2-(4'-vinylbenzyl) cyclopentanone of formula I or III, carboxylating the produced vinyl bromide compound by electrolyzing in DMF in the presence of carbon dioxide and hydrogenating the product in the presence of a reduction catalyst.
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