The present invention provides a process for the preparation of crude
1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydro-5-isobenzofura-
n carbonitrile base with substantially low levels of impurities by
arresting the formation of substantial amount of carboxamide impurity,
high molecular weight impurities and suppressing the formation of
desmethylcitalopram besides taking the cyanide exchange reaction to near
completion and thus avoiding an extensive and expensive purification
process.