Dihydroacridine, substituted

Substitution of the nine position is a common transformation for acridines. An optimized method for preparing the 9-carboxamides uses BOP/DMF <99SC4341>. Reaction of 9-isothioacridines with the sodium anion of diethylmalonate is followed by alkylation with bromoacetate to afford the spiro[dihydroacridine-9(10i/)-thiazolidines] <99H(51)137>. 

Anodic oxidation of 9,9-substituted 9,10-dihydroacridines in CH3CN-Bu4NC104 at a Pt electrode gives a cation-radical that dimerizes to a 2,2 -biacridine system such a dimer is further oxidizable to a quinonoid... 

It has been demonstrated that visible light irradiation of the absorption band of AcrH + in the presence of organometallic compounds and alkenes and alkylbenzenes in MeCN results in efficient C-C bond formation between these electron donors and AcrH+ via photoinduced electron transfer from the donors to the singlet excited state of AcrH+ to yield the alkylated or allylated adducts selectively [89-91], The AcrH+ is also photoreduced by ethylbenzene and other alkylbenzenes to yield the corresponding 9-substituted-10-methyl-9,10-dihydroacridine [92] ... 

Methyl- 10-hydroacridinyl radicals are involved in the electrochemical oxidation of 10-methyl-9,10-dihydroacridines with at least one of the 9-positions unsubstituted. If both 9-positions are substituted, 10-hydroacridinyl radicals are not involved since loss of a methylene proton from the initially formed 9,10-dihydroacridine cation-radical is impossible.261... 

Varying amounts of acridone are produced along with carbazoles when salicyl 2-azidobenzoates (36) are pyrolysed at 400°C. The acridone predominates with the phenyl ester (M.G. Clancy, M.M. Hesabi and 0. Meth-Cohn, Cbm. Comm., 1980, 1112) and later work indicates that the amount of acridone increases as the leaving group efficiency of OR increases (.idem, J. chem. Soc. Perkin I, 1984, 429). Spray pyrolysis of 2,6-disubstituted phenyl 2-azidobenzoates leads to a mixture of 4-substituted 9,10-dihydroacridine and the corresponding acridine, possibly involving ipso attack by the nitrene. 

Electron transfer processes, kinetics, and mechanisms for the oxidation of 10-methyl-9,10-dihydroacridine, as the model compound, and other 9-substituted l-methyl-9,10-dihydroacridines have been the subject of many studies [44, 207-211]. In particular, it has recently been found in our laboratory that nanocrystalline Ti02 with CdS nanoparticles embedded in its pores can accelerate the C-H functionalization of azaaromatic compounds. Indeed, the CdS/Ti02 composite proved to be an effective visible-light-driven photocatalyst for the oxidative step of the reaction of A -alkylacridinium salts with arylamines (Scheme 68). 

The methiodide reacted with Grignard reagents to give the corresponding 10-substituted-9,10-dihydroacridines (49). 

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