5-Bromo-1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran oxalate

It serves as a precursor to the cyanophthalan ring system, in which the 5-bromo group is substituted with a cyano group via metal-catalyzed cyanations, such as using CuCN or similar cyanating agents, followed by resolution to obtain the active (S)-enantiomer. 5-Bromo-1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran, often used as its oxalate salt, is a key intermediate in the synthesis of the antidepressant Escitalopram (S-citalopram) and citalopram.