9,10-Dihydroacridine derivatives

Alkylation of acridine at C-9 occurs on reaction with O)-alkozyalkyl lithium compounds and subsequent oxidation of the resulting 9,10-dihydroacridine derivative (16). Various functional group interconversions are possible leading notably to acridines bearing phosphorus containing substituents at the 9-position (L. Horner and W. Hallenbach, Phosphorus and Sulphur, 1984, 173). 

Protonated pyridines and derivatives readily undergo acylation at C-2 or C-4 (Table 28) (76MI20503). Acyl radicals are usually generated either by hydrogen abstraction from aldehydes (Scheme 210), or by oxidative decarboxylation of a-keto acids (Scheme 211). In the former case (Scheme 210) with acridine as the substrate, reduction can take place to give a dihydroacridine. 

Acridine. Acridine is hydrogenated to 9,10-dihydro derivative over Raney Ni at 25°C and over copper-chromium oxide at 150°C in dioxane.9101 Over Raney Ni at 100°C, acridine or 9,10-dihydroacridine is hydrogenated to a mixture of as- and s-octahydro and dodecahydro derivatives. However, over copper-chromium oxide at 190°C, as-octahydro derivative is formed in high selectivity, although a small amount of dodecahydro derivative is also formed.9 The formation of... 

Dihydroacridines arise from the reaction of ketones with diarylamines at elevated temperatures and pressures, cyclic ketones lead to spirodihydroacridines (23). The 9-aryl spiro derivatives exist in a twisted boat conformation, with the aryl substituent pseudo equatorial, as do the analogous S3rmmetrical 9.9-diaryl dihydroacridines (W, Tritschler et al, Ber., 1984, 117. 2703). 

A C- nmr study of 9,10-dihydroacridines indicates that there is very little delocalisation of the nitrogen lone pair of electrons into the aromatic rings in the case of the 10-acetyl derivative (E. Ragg et al. J. chem. Soc. Perkin II, 1983, 1289). Although 9-hydroxy-l,2,3,4-... 

Hydride transfer reactions from NADH analogues to high-valent metal-oxo species provide excellent opportunity to clarify such a mechanistic difference by comparing the hydride transfer reactions with those with /)-benzoquinone derivatives, which have been discussed in the previous section. A series of NADH analogues, 10-methyl-9,10-dihydroacridine (AcrH2) and its 9-subsituted derivatives (AcrHR R =... 

Reduction of acridine occurs in the pyridine ring (with Zn/HCl) giving rise to 9,10-dihydroacridine (12) and in the benzene rings (by catalytic hydrogenation with Pt in hydrochloric acid) providing the pyridine derivative 13 ... 

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