290362-10-6Relevant articles and documents
A PROCESS FOR THE PREPARATION OF 2- 2- 4-(DIPHENYLMETHYL)-1-PIPERAZINYL]ETHOXY ACETIC ACID COMPOUNDS OR SALTS THEREOF
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Page/Page column 5, (2008/06/13)
2-{2-[4-(diphenylmethyl)-1-piperazinyl]ethoxy}acetic acid compounds of general formula (I) wherein R and R 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.
