Synthesis with Electrophilic Aromatic Substitution

I found a synthesis in an article called Synthesis, Electrophilic Substitution and Structure-Activity Relationship Studies of Polycyclic Aromatic Compounds Towards the Development of Anticancer Agents, which was published in the Current Medicinal Chemistry journal in 2001. The article is about polycyclic aromatic hydrocarbons (PAH) which are considered potentially carcinogenic. Substituted PAH derivatives may serve as anticancer agents, and as chemotherapeutics. This article presents a review of their use. Electrophlic substituation reactions are used during the synthesis of these new compounds. Here is a picture of one of the two of the steps which use electrophilic aromatic substitution:

This depicts a halogenation by replacing a hydrogen atom on the benzene ring with a bromine in each reactant. These compounds underwent bromination regioselectively in a single site. There was another step of this synthesis to make anitcancer agents from substituted  polycyclic aromatic hydrocarbons which involved an electrophilic aromatic substitution.

This step is a nitration of one of the benzene rings of the reactant. During the study, it was shown that benz[a]aceanthrylene (62) and indeno[1,2,3-cd]pyrene (63) produced single mononitro derivatives 64 and 65. The conformation of the nitro derivatives was important in determining the mutagenic activities. It is proposed that suitably substituted polycyclic aromatic compounds can inhibit cancer cellgrowth even though there was a concept that these are only carcinogenic in nature. The hope is to see potent antitumor drugs with novel mechanisms of action based on the chemistry described above.

Reference: Banik B, Becker F. Synthesis, electrophilic substitution and structure-activity relationship studies of polycyclic aromatic compounds towards the development of anticancer agents. Current Medicinal Chemistry [serial online]. October 2001;8(12):1513-1533. Available from: MEDLINE, Ipswich, MA. Accessed March 6, 2011.