Acridan derivatives

Perkizas G, Nikokavouras J. Substituent effect on the chemiluminescence quantum efficiency of some acridan derivatives. Monatsh Chem 1983 114 3-11. 

Xanthene and acridane derivatives are pharmaceutically active compounds, as well as natural compounds, and their synthesis has attracted much attention. Recently, Klussmann and co-workers reported the oxidative coupling of xanthene and other activated benzylic compounds with carbon-based nucleophiles such as ketones. The reaction proceeded smoothly under... 

Several N-methyl-9-acridinecarboxylic acid derivatives (e.g., 10-methyl-9-acridinecarboxylic chloride and esters derived therefrom [39]) are chemiluminescent in alkaline aqueous solutions (but not in aprotic solvents). The emission is similar to that seen in the CL of lucigenin and the ultimate product of the reaction is N-methylacridone, leading to the conclusion that the lowest excited singlet state of N-methylacridone is the emitting species [40], In the case of the N-methyl-9-acridinecarboxylates the critical intermediate is believed to be either a linear peroxide [41, 42] or a dioxetanone [43, 44], Reduced acridines (acridanes) such as N-methyl-9-bis (alkoxy) methylacridan [45] also emit N-methylacridone-like CL when oxidized in alkaline, aqueous solutions. Presumably an early step in the oxidation process aromatizes the acridan ring. 

Analogously to the firefly luciferin/luciferase system, the general chemiluminescence mechanism postulated for 9-carboxyacridinium derivatives proposes the 1,2-dioxetanone 45 as high-energy intermediate However, this 1,2-dioxetanone is the only intermediate that has not yet been isolated . The cleavage of the peroxidic ring presumably results in the release of CO2 and the formation of an acridan residue in its electronically excited state (Scheme 32). 

Photoaddition of nucleophiles to heterocycles is often observed.1 Irradiation of acridine and its quaternary salt in ethanol produced 9,9 -bisacridan (151) as the major product besides a little acridan and 9a-hydroxyethylacridan.207 The reaction mechanism is most likely a hydrogen abstraction from the alcohol by the excited molecule, followed by competitive radical combination to yield 151. Irradiation of an aqueous solution of alloxan monohydrate and its derivatives produces an alloxantin-type dimer (152 R = H, Me, Et) by combination (at the 5-position) of a radical intermediate.208... 

Fluoride ion causes deproteclion of 36 and the resultant aryloxy anion decomposes with chemiluminescence to diisopropyl ketone and a (3-methoxycarbonyl derivative of the naphthol <97TL411>. Other 1,2-dioxetanes containing an acridane 10-acetate group have been investigated as potential fluorescent probes <97TL841>. 

After induction by lO-carboxymethy-9-acridan-one, murine bone marrow-derived macrophages produced two activities of interferon P differing in the degree of glycosilation (Brehm et al. 1986). 

A second tempting possibility is a mechanism which has been proposed for the chemiluminescent oxidation of certain imidazole , acridane , and indole , derivatives. Its essence is expressed in equation (23), where a 4-ring peroxide collapses, leaving one of the fragments in an electronically excited state. This scheme is attractive... 

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