L. S. Klimenko

Experimental and quantum chemical study of the reactions of 1,10-anthraquinones with alcohols and amines

Abstract The primary stage of the reaction between 9-aryloxy-1,10-anthraquinones and methanol is the nucleophilic 1,4-addition which gives rise to the adduct, corresponding to 1-hydroxy-9-methoxy-9-aryloxy-10-anthrone. The reaction of 9-aryloxy-1,10-anthraquinones with the primary aliphatic and aromatic amines results in the formation of 9-alkyl(aryl)amino-1,10-anthraquinones that are in a tautomeric equilibrium with 1-hydroxy-9,10-anthraquinone-9-alkyl(aryl)imines. The quantum chemical calculations of the enthalpy of 9-amine-1,10-anthraquinone isomerization are in agreement with the experimentally recorded influence on the tautomeric equilibrium of the nature of amine, solvent, and substituent in the anthraquinone nucleus. The data of quantum chemical calculations confirm the addition-elimination mechanism of the reaction of 1,10-anthraquinones with amines.

Photocyclization of 2-azido-1-(4-tert-butylphenoxy)-9,10-anthraquinone in the presence of substituted phenols

New types of phototransformations in the quinone series, viz., photocyclizations of 1-aryloxy-2-azido-9,10-anthraquinone in the presence of phenols, were studied. The photolysis affords mainly 5H-naphtho[2,3-c]phenoxazine-8,13-diones, in which the nitrogen atom is covalently bound to the phenyl ring of the attached phenol. As a result, complex polycyclic derivatives of phenoxazines were prepared in high yields in one step.

Crown-containing naphtho- and anthraquinones: synthesis and complexation with alkali and alkaline-earth metal cations

Novel naphtho- and anthraquinones conjugated with benzo- and dibenzo-18-crown-6 ethers were obtained. Their complexation reactions with Groups Ia and IIa metal perchlorates in acetonitrile were studied by spectrophotometric titration. In most cases, the complexation involves the crown ether moiety; the stability constant of the resulting complex decreases in the following order: Ba2+ > Sr2+ > Ca2+ > Na+. For crown-containing anthraquinone imines characterized by prototropic “imine-enamine” tautomerism, the complexation shifts the equilibrium toward the imine species, which allow these compounds to be classified among a rarely occurring type of tautomeric chromoionophores. Unlike other cations, the magnesium ions preferably interact with the heteroatoms of the anthraquinone moiety (the imine N atom, the OH group, and the carbonyl O atom of the benzamido group); the logK value reaches 4.4. The chelation to the Mg2+ cations and the effect of the complexation on the tautomeric equilibrium was confirmed by quantum chemical calculations.

Synthesis of 1-phenyl-6H-anthra[1,9-b,c]furan-6-one (furanoanthrone) derivatives by the reaction of 1-acyloxy-9,10-anthraquinones with benzyl cyanide

The reactions of various I-acyloxyanthraquinones with benzyl cyanide in DMSO in the presence of K2CO3 were studied. 1-Phenyl-6H-anthra[1,9-b,c]furan-6-one derivatives are formed as the main reaction products. In the case of unsubstituted I-acyloxyanthraquinones, 1-phenyl-6H-anthra[1,9-b,c[furan-6-one and I-phenylanthra[1,9-b,clpyran-2,l-dione were isolated. It was shown that furanoanthrones can be synthesized in two steps via the corresponding pyronoanthrones.

Photochromism of Quinoid Compounds

Abstract The paper presents the results of studies on the photochromic transformation mechanisms for three classes of quinone derivatives. Photoisomerization of the para-quinone to the anaquinone due to photochemical migration of hydrogen, aryl, or acyl groups is common to these processes. The mechanism of photochromic transformations of 1-alkyl- and 1-acyloxyanthraquinones has been investigated in detail. The primary photochemical steps of these processes - the migrations of hydrogen or an acyl group - are adiabatic photochemical reactions at the triplet potential energy surface. Variation of substituents in the anthraquinone ring, in the alkyl group of 1-alkylanthraquinones, and particularly in the acyl group of 1-acyloxyanthraquinones makes it possible to change (from several microseconds to seconds) the lifetimes of coloured photoinduced products at room temperature.

Reactions of photoinduced 9-aryloxy-1,10-anthraquinones

Abstract The reactions of ana-anthraquinones with nucleophiles have been studied in order to find the photochromic compounds with the lowest fatigue. The primary stage of the reaction between 9-aryloxy-1,10-anthraquinones and nucleophiles (water, alcohols, primary amines) is the reaction of nucleophilic 1,4-addition. The electron withdrawing substituents in the anthraquinone increase and the electron donor ones substantially decrease the reaction rate constant favouring the stability of photoinduced 1,10-anthraquinones. All the experimental data on the reactivity of ana-quinones are in a fairly well agreement with the results of AM1 calculations of the electronic properties of anaquinones.

Synthesis of 5H-naphtho[2,3-c]phenothiazine-8,13-diones from 1-arylthio-2-azidoanthraquinones

Thermolysis of 1-arylthio-2-azidoanthraquinones in DMSO at 150 °C afforded substituted 5H-naphtho[2,3-c]phenothiazine-8,13-diones. These compounds were also formed upon photolysis of azides at 77 K and were prepared in quantitative yields by the reactions of 1-arylthio-2-azidoanthraquinones with KOH in DMSO at 20 °C.

Photochemical and thermal rearrangements of 2-arylamino-1-(4-tert-butylphenoxy)-9,10-anthraquinones

Photochemical transformations of 2-arylamino-1-(4-tert-butylphenoxy)-9,10-anthraquinones involve migration of thetert-butylphenyl group either to theperi-located carbonyl oxygen to give 2-arylamino-9-(4-tert-butylphenoxy)-1,10-anthraquinones or to the nitrogen atom to give 2-aryl(4-tert-butylphenyl)amino-1-hydroxy-9,10-anthraquinones (typical products of the Smiles rearrangement).

Photolysis of 1,2-anthraquinone diazide in aromatic hydrocarbons

It has been determined that the main products of photolysis of 1,2-anthraquinone diazide in benzene, toluene, anisole, nitrobenzene, and pyridine are the corresponding 1-hydroxy-2-arylanthraquinones that form as a mixture ofortho, meta, andpara isomers with significant content of themeta isomer (40–55%).

Influence of peripheral substituents on the stability of sandwich-type complexes of crown ether-containing anthraquinoneimines

ABSTRACT Benzo-15-crown-5 ether derivatives of 1-hydroxy-9,10-anthraquinone-9-imine bearing a substituted benzoylamino group, NHCO(p-C6H4NO2) or NHCOC6F5, in position 2 were synthesized by a photochemical method. The structure of the fluorine-containing compound was determined by single-crystal X-ray diffraction. Both synthesized dyes, as well as their analogue without substituents on the benzoyl ring, are capable of binding Sr2+ and Ba2+ to form sandwich-type 2:1 (ligand:metal) complexes. In MeCN, these complexes exhibit higher stability constants (K2:1) than the corresponding 1:1 complexes (K1:1). The para-substitution of the benzoyl ring with a nitro group leads to a significant increase in both the K2:1 constant and the K2:1/K1:1 ratio. The fluorination of the benzoyl ring insignificantly affects the stability of sandwich complexes. Density functional theory calculations showed that this is related to steric interactions in the benzoylamino group. The calculated structures of the dyes and their sandwich complexes with Ba2+ are consistent with the 2D NOESY data. Graphical Abstract