Sustainable Access to Acridin-9-(10H)ones with an Embedded m-Terphenyl Moiety Based on a Three-Component Reaction

A Ce(IV)-catalyzed three-component reaction between chalcones, anilines and β-ketoesters followed by a microwave-assisted thermal cyclization afforded 1,3-diaryl-1,2-dihydroacridin-9(10H)-ones. Their microwave irradiation in nitrobenzene, acting both as solvent and oxidant, afforded fully unsaturated 1,3-diarylacridin-9(10H)-ones, which combine acridin-9-(10H)one and m-terphenyl moieties. Overall, the route generates three C-C and one C-N bond and has the advantage of requiring a single chromatographic separation.     

Effect of Acridine Derivatives on the Dissolution of α-Brass

Acridine derivatives as inhibitors of diffusion- and diffusion–kinetic-controlled dissolution of -brass are studied. Inhibition coefficients of the dissolution and its steps correlate with parameters of a standard reaction series and wavelengths of the longest-wave absorption band of the electronic spectrum.     

Diethyldisulfoammonium chlorometallates as heterogeneous Brønsted–Lewis acidic catalysts for one‐pot synthesis of 14‐aryl‐7‐(N‐phenyl)‐14H‐dibenzo[a,j]acridines

A new series of Brønsted–Lewis acidic diethyldisulfoammonium chlorometallates, [DEDSA][FeCl₄] and [DEDSA]₂[Zn₂Cl₆], were synthesized as solid materials from the reaction of [(Et)₂N(SO₃H)₂][Cl] ionic liquid with transition metal chlorides (FeCl₃ and ZnCl₂) at 80 °C in neat condition for 2 h. The chlorometallates were fully characterized using various spectroscopic and analytical techniques such as Fourier transform infrared, UV–visible and Raman spectroscopies, powder X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray and thermogravimetric analyses, Hammett acidity and elemental analyses. Their catalytic activity was studied as reusable heterogeneous catalysts for the three‐component synthesis of novel 14‐aryl‐7‐(N‐phenyl)‐14H‐dibenzo[a,j]acridines under solvent‐free conditions at 100 °C.     

Aromatization with dearylation on Hantzsch cyclocondensation of 4-(dimethylamino)benzaldehyde,cyclohexane-1,3-diones,and some 1,3-[N,C]dinucleophiles

The Hantzsch three-component cyclization of 4-(dimethylamino)benzaldehyde, cyclohexane-1,3-diones, and some 1,3-[N,C]-dinucleophiles (5-amino-3-methyl-1-phenylpyrazole, 3,5-dimethoxyaniline, and 4-amino-1,3-dimethylpyrimidine-2,6-dione) proceeds in boiling acetic acid with the splitting off N,N-dimethylaniline and the formation of polycondensed heterocyclic sytems with a γ-unsubstituted pyridine ring (pyrazolo[3,4-b]quinoline, acridine, and pyrimido[4,5-b]quinoline). Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 244-251, February, 2009.     

A simple and effective approach to the synthesis of pyrido[4,3,2-mn]pyrrolo[3,2,1-de]acridine skeleton of arnoamines A and B, pentacyclic marine alkaloids from the ascidian Cystodytes sp.

Starting from ethyl 5-hydroxy-2-methyl-1-phenylindole-3-carboxylate, a simple and effective approach to the synthesis of pyrido[4,3,2-mn]pyrrolo[3,2,1-de]acridine skeleton of arnoamines A and B, unique pentacyclic alkaloids from the ascidian Cystodytes sp., has been developed. Synthesis of this ring system involves seven steps and produces ethyl 4-methoxy-1-methylpyrido[4,3,2-mn]pyrrolo[3,2,1-de]acridine-2-carboxylate in 41.5% overall yield.     

Efficient Protocol for Synthesis of Pyrazolo[3,4-a]acridines

A new class of pyrazolo[3,4-a]acridines have been prepared. The synthon acridones were obtained in very good yield by a one-pot reaction of 2-amino-5-chloro or nitro substituted benzophenones with 1,3-cyclic diketones in the presence of freshly prepared Eaton’s reagent without solvent, using Friedländer synthesis. The intermediates were reacted with ethylformate followed by hydrazine hydrate to afford pyrazolo[3,4-a]acridines. All of the compounds were purified by recrystallization only, and no chromatographic workup was required. The structures of the synthesized compounds were deduced by spectroscopic techniques, including single-crystal x-ray diffraction.     

Novel ring enlargement of cyclobutane derivatives by oxidative radical decarboxylation

Cycloadducts obtained via [2+2] photocycloaddition between an unsaturated oxoacid and cycloalkene are readily opened by irradiation at 366nm, in the presence of catalytic amounts of acridine in toluene and under an oxygen atmosphere, leading after treatment with dimethylsulfide to the formation of polycyclic diketones or ketolactones.     

Chiral 5-(diphenylphosphanyl)-1,2,3,4-tetrahydroacridines: new N,P-ligands for asymmetric catalysis

Three chiral 5-(diphenylphosphanyl)-1,2,3,4-tetrahydroacridines, as first representative examples of a new class of chiral N,P-ligands were prepared from (+)-nopinone, (+)-camphor and 5α-androst-2-en-17-one. These ligands have been assessed in the enantioselective palladium-catalysed allylic substitution of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. Enantioselectivity up to 74% has been obtained.     

Syntheses of 7H-pyrido-and 7H-pyrano[2,3,4-kl]acridin-2(3H)-ones from 9-chloroacridines

A method for peri-annulation of the pyridine or pyran ring to acridine was developed and used to obtain 7H-pyrido-and 7H-pyrano[2,3,4-kl]acridin-2(3H)-ones. The peri-groups were formed by a reaction of 9-chloro-1-nitroacridine with a CH-acid (malononitrile, ethyl cyanoacetate, and ethyl malonate) followed by reduction of the nitro group, or by a reaction of 1-amino-10-methylacridone with PCl₅ and then with a CH-acid. Replacement of the chlorine atom in 9-chloro-1-methoxyacridines by the residue of the CH-acid with subsequent heating in an acidic medium afforded 7H-pyrano[2,3,4-kl]acridin-2(3H)-ones, which belong to a novel heterocyclic system. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1605–1610, September, 2006.