Acridine reductive dimerization

Reductive dimerization of benzene [246], cyano biphenyl ether [247], pyridine [248], and acridine [249] derivatives has also been investigated. Radical anions of diesters of pyridine and benzene undergo rapid reversible dimerization (A dim = 10 -10 M" s" ) [250]. 

Radical anions of acridine (95) dimerize in DMF to give the corresponding dimer dianion [270] (Table 21). The reduction remained a 1-F process upon addition of 10% (v.v) water but led to a fivefold increase in the value of On a voltammetric time scale, the dimerization appeared irreversible in the absence as well as in the presence of water. On a preparative scale, the dimer 9,9, 10,10 -tetrahydro9,9 -biacridyl could be isolated... 

Acridine (123) is polarographically reducible both in acid and alkaline solution.144 In strongly acid solution a single one-electron wave is found, and from a preparative reduction compounds dimerized at C-9 were isolated.54 In less acid and in alkaline solution 2 one-electron waves are found, the latter probably resulting in 9,10-dihydroacridine (124). 

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