1.3- Disubstituted isobenzofuran

Recently, reactions of PQ and related quinones with 1,3-disubstituted isobenzofurans have been reported 184> to involve 1,4-cycloaddition as well as cleavage of the furan ring. 

Most of the stable isobenzofurans are 1,3-diaryl substituted, and are deep yellow. Such compounds are available via the partial reduction, and dehydrating cyclisation of 1,2-diaroylbenzenes. Both 1-mono- and 1,3-disubstituted isobenzofurans are available from phthalides by Grignard addition then ehmination of water. ... 

This same oxidation level situation - a disubstituted benzene with aldehyde (ketone) ortho to carbinol ready for cyclisation and dehydration to an isobenzofuran - can be achieved in alternative ways phthalaldehyde can be mono-acetalised, then the remaining aldehyde reduced, or lithiation technology can be utilised, as shown below. 

Citalopram a disubstituted racemic l-(3-dimethylaminopropyl)-l-phenyl-isobenzofuran derivative (fig. 7) is a highly selective and potent inhibitor of the 5-HT transporter in vitro as well as in vivo. Citalopram is used in clinical practice as an antidepressant. 

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