Process for the preparation of 1 - (3-dimethylaminopropyl) -1 - (4-fluorophenyl) -1,3-dihydroisobenzofuran-5-carbonitrile

摘要

The present invention is directed to novel processes for the preparation of citalopram comprising halogenation of a phthalide compound of formula II, wherein R is a suitable group to be changed to CN, to afford an acid halogenide compound of formula III wherein R is as defined as above and X is halogen, and thereafter obtaining citalopram through two successive reactions with suitable organometallic halides or organoboranes or by a reaction with organometallic 4-fluorophenylhalide or 4-fluorophenylborane followed by reduction and alkylation, and an exchange of R to cyano to afford citalopram. The order of the reactions can be varied depending for example on the starting compound used.