Reactivity of the acridine ring: A review

Acridine derivatives are potent biological fluorescent probes, as well as anti-microbial, anti-bacterial, anti-tumor, and DNA-binding agents. The acridinic pattern is included in many therapeutic agents, with more than 600 articles published in 2002 alone. Usual methods for the synthesis of acridines involves the condensation of adequately functionalized anilines and o-halogenobenzoic acid derivatives, or condensation of diphenylamine or diphenylmethane, along with several other steps to give the desired scaffold. However, direct ring functionalization methods are also an interesting synthetic pathway to widely functionalized acridines because they eliminate many synthetic steps and facilitate the synthesis of complex polycyclic structures. This review comprises 138 references that focus on the reactivity of the acridine ring since the publication of Acheson's 1973 book 'The Acridines'. It covers particularly regioselective reactions that occur directly on the acridine ring; these include reduction, electrophilic and nucleophilic additions, and substitutions, as well as radical reactions. 1 Introduction 2 Reduction of the Acridine Ring 3 Reactivity of Position 10 4 Reactivity of Position 9 4.1 Reactivity of Acridines 4.2 Reactivity of Acridiniums 4.3 Reactivity of N-Oxides 5 Reactivity of Positions 4 and 5 6 Reactivity of Positions 1 and 8 7 Reactivity of other Positions 8 Prospects and Conclusion