Routes of electrophilic substitution in phthalic and 4-dimethylaminophthalic anhydrides

Molecular structure and the direction of electrophilic substitution in phthalic and 4-dimethylaminophthalic anhydrides were investigated using semiempirical quantum chemistry methods. It was shown that the 4-position of phthalic anhydride is the most probable for electrophilic attack. It is established that the introduction of dimethylamino group into the 4-position in phthalic anhydride results in increasing ability of the molecule to electrophilic substitution and the positional selectivity.