[EN] A PROCESS FOR THE PREPARATION OF 2-{2-[4-(DIPHENYLMETHYL)-1-PIPERAZINYL]ETHOXY}ACETIC ACID COMPOUNDS OR SALTS THEREOF<br/>[FR] PROCEDE DE PREPARATION DE COMPOSES D'ACIDE ACETIQUE 2-{2-[4-(DIPHENYLMETHYL)-1-PIPERAZINYL]ETHOXY} OU DE SELS DE CEUX-CI
申请人:GEA FARMACEUTISK FABRIK AS
公开号:WO2000052000A1
公开(公告)日:2000-09-08
2-2-[4-(diphenylmethyl)-1-piperazinyl]ethoxy}acetic acid compounds of general formula (I) wherein R?1 and R2¿ independently represent hydrogen, halogen, lower alkoxy or trifluoromethyl, or salts thereof are prepared by reacting a corresponding 2-[4-(diphenylmethyl)-1-piperazinyl]ethanol with a 2-substituted acetaldehyde dialkylacetal in the presence of a proton acceptor in an inert solvent to form a corresponding diphenylmethylpiperazinoethoxyacetaldehyde dialkylacetal, and thereafter hydrolysing the acetal to the corresponding aldehyde, catalysed by a proton donor, and then oxidising the aldehyde to the acid (I) by means of a suitable oxidation agent. If desired, the acid (I) is converted into a salt thereof. The process is cheap, easy to perform and gives a high yield. The most interesting compound is 2-2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]-ethoxy}acetic acid in the form of its dihydrochloride known by the generic name of cetirizine. The 2-2-[4-(diphenylmethyl)-1-piperazinyl]ethoxy}acetaldehyde compounds and their dialkylacetals are novel compounds.