B. V. Lichitsky

Photochromic dihetarylethenes. 7. Synthesis of bis(thienylazoles), photochromic analogs of diarylethenes

Procedures for the synthesis of 4,5-bis[2,5-dimethyl(3-thienyl)]-1,3-azoles based on 1,2-bis[2,5-dimethyl(3-thienyl)]-2-hydroxyethan-1-one, 2-chloro-1,2-bis[2,5-dimethyl(3-thienyl)]ethan-1-one, and 1,2-bis[2,5-dimethyl(3-thienyl)]ethane-1,2-dione were developed. Dithienylethenic compounds in which the thienyl rings are linked through the azole rings exhibit photochromic properties.

Photochromic dihetarylethenes. 11. Synthesis and photochromic properties of diarylethenes containing furan or furopyrimidine bridges

Procedures were developed for the synthesis of substituted bis(2,5-dimethyl-3-thienyl)furans based on 1,2-bis(2,5-dimethyl-3-thienyl)-2-hydroxyethanone. Dithienylethene structures in which the ethene fragment is involved in the furan or furopyrimidine system possess photochromic properties and their open forms exhibit fluorescence.

Photochromic dihetarylethenes. 17. Synthesis and photochromic properties of dithienylethenes containing new heterocyclic bridging fragments

Procedures were developed for the synthesis of substituted bis(2,5-dimethyl-3-thienyl)ethenes containing the imidazol-2-one, 1,3-dioxol-2-one, or 1,3-oxazol-2-one fragments as ethene bridges. These compounds were demonstrated to exhibit the photochromic properties. The cyclic forms of some imidazolone and oxazolone photochromes possess high thermal stability. The structure of photochromic 4,5-bis(4-acetyl-2,5-dimethyl-3-thienyl)-3-methyl-2,3-dihydro-1,3-oxazol-2-one was established by X-ray diffraction analysis. The molecule adopts an anti-parallel conformation similar to that of perfluorocyclopentene-bridged dithienylethenes.

Three-Component Condensation of 2,4-Diaminoselenazole with Aldehydes and Meldrum’s Acid: Synthesis of 7-Aryl(alkyl)-Substituted 2-Amino-6,7-dihydro-4H-selenazolo[4,5-b]pyridin-5-ones

A method for the synthesis of 7-aryl(alkyl)-substituted 2-amino-6,7-dihydro-4H-selenazolo [4,5-b]pyridin-5-ones 5 based on three-component condensation of in situ–generated 2,4-diaminoselenazole 7 with aromatic (aliphatic) aldehydes 9 and Meldrums acid 10 was developed.

Reactions of cyclic enaminoketones with benzylidenemalononitriles. Synthesis of new fused heterocyclic systems containing the 1,4-dihydropyridine fragment

The reactions of cyclic enaminoketones with benzylidenemalononitriles were examined and a new procedure was developed for the synthesis of fused heterocyclic systems containing the 1,4-dihydropyridine ring, viz., thienopyrimidoquinolines and furopyrimidoquinolines. The characteristic features of the reactions and the structures of the resulting compounds were investigated.

Synthesis of 12-aryl-1-oxo-1,2,3,4,5,12-hexahydroindolo-[2,1-b]quinazoline-6-carbonitriles by recyclization of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles

A general and convenient method for the synthesis of 12-aryl-1-oxo-1,2,3,4,5,12-hexahydroindolo[2,1-b]quinazoline-6-carbonitriles was proposed. The method is based on the recyclization of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles. The structure of 12-(3-methoxyphenyl)-8-methyl-1-oxo-1,2,3,4,5,12-hexahydroindolo[2,1-b]quinazoline-6-carbonitrile was studied by X-ray diffraction analysis.

Synthesis and optical properties of new photochromic systems based on 1,2-bis(2-methylbenzo[b]thien-3-yl) hexafluorocyclopentenes and 5,7-dihydro-1H-1,2,5,7,8-pentaaza-s-indacen-6-one or 1,7-dihydro-5-thia-1,2,7,8-tetraaza-s-indacen-6-one derivatives

New photochromic molecules based on 1,2-bis(2-methylbenzo[b]thien-3-yl)hexafluorocyclopentenes and fluorescent 5,7-dihydro-1H-1,2,5,7,8-pentaaza-s-indacen-6-one or 1,7-dihydro-5-thia-1,2,7,8-tetraaza-s-indacen-6-one derivatives were synthesized via nucleophilic substitution. Photochromic properties of the compounds and composite mixtures of fluorophores and photochrome were investigated. GRAPHICAL ABSTRACT

Three-component condensation of 5-aminoimidazole derivatives with aldehydes and Meldrum’s acid. Synthesis of 3,4,6,7-tetrahydroimidazo[4,5-b]pyridin-5-ones

A convenient method for the synthesis of the earlier unknown substituted 3,4,6,7-tetrahydroimidazo[4,5-b]pyridin-5-ones was developed based on a three-component condensation of 5-aminoimidazole derivatives, aldehydes, and Meldrum’s acid. Unstable aminoimidazole derivatives were readily formed in situ by decarboxylation of 5-amino-4-imidazolecarboxylic acids in acidic medium at room temperature, whose sodium salts were obtained by the alkaline hydrolysis of the corresponding, readily available esters.

Three-component condensation of 3-aminothiophene derivatives with isatines and Meldrum’s acid. Synthesis of 2,5′-dioxo-3′-phenyl-5′,6′-dihydro-4′H-spiro[indoline-3,7′-thieno[3,2-b]pyridine]-2′-carboxylic acids

A method for the synthesis of 2,5′-dioxo-3′-phenyl-5′,6′-dihydro-4′H-spiro[indoline-3,7′-thieno[3,2-b]pyridine]-2′-carboxylic acids was elaborated based on the three-component condensation of 3-aminothiophenes, Meldrum’s acid, and isatines.

Reactions of cyclic enehydrazino ketones with arylidenemalononitriles. Synthesis of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles

A general and convenient method for the synthesis of 11-aryl-1-oxo-2,3,4,5,10b,11-hexahydro-1H-indolo[2,3-b]quinoline-10b-carbonitriles was elaborated. The method is based on the novel stereoselective rearrangement of fused N-arylamino-substituted 1,4-dihydropyridines. The structures of the synthesized compounds were studied using 1H NMR spectroscopy and X-ray diffraction analysis.