Simulation of optical response to complex formation of crown-containing 2-styrylbenzothiazoles with alkaline-earth metals

The photochromic properties and complex formation of 2-styrylbenzothiazoles containing different crown ether moieties with alkaline-earth metals were described using optical methods, NMR spectroscopy, and HPLC. The large ionochromic effect and fluorescence quenching on complex formation with alkali-earth metal cations were found for 2-styrylbenzothiazole containing the phenylazacrown ether moiety. The small ionochromic effect and fluorescence enhancement of complex formation with alkali-earth metal cations were found for 2-styrylbenzothiazole containing the benzocrown ether moiety. cis-Isomers of 2-styrylbenzothiazoles were stable in the dark in acetonitrile. The method for separation of cis-isomers of 2-styrylbenzothiazoles by HPLC was proposed.     

4-Hydroxy-2-quinolinones 128. Bromination of N-allyl-4-hydroxy-2-oxo-1,2-dihydroquinolines and pyridines unsubstituted in position 3

Bromination of N-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline and N-allyl-5-ethoxycarbonyl-4-hydroxy-6-methyl-2-oxo-1,2-dihydropyridine is accompanied not only by closing of a five membered oxazole ring but also by a second bromination of the 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]-derivatives formed at position 4. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1365–1373, September, 2007.     

4-hydroxy-2-quinolones. 124. Synthesis and structure of ethyl 2-bromomethyl-5-oxo-1,2,6,7,8,9-hexahydro-5H-oxazolo-[3,2-<Emphasis Type="Italic">a</Emphasis>]quinoline-4-carboxylate

The hydrogenation of the benzene part of the molecule in N-allyl-substituted 4-hydroxy-2-quinolinones does not affect the nature of their bromination by molecular bromine and gives 2-bromomethyl-5-oxo-1,2,6,7,8,9-hexahydro-5H-oxazolo[3,2-a]quinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1180–1188, August, 2007.     

Synthesis of crown-containing 2-styrylbenzothiazoles. Effect of alkali metal cations on the condensation of crown-ether benzaldehydes with 2-methylbenzothiazole

Methods for the synthesis of unknown 2-styrylbenzothiazoles containing crown ether moieties with different combinations of O, S, and N-heteroatoms based on the Wittig reaction or condensation of 2-methylbenzothiazole with crown-ether benzaldehydes in the presence of strong bases or acids are proposed. The condensation in the presence of bases is accompanied by complex formation with participation of the crown ether moiety of the benzaldehyde. The complex formation has a pronounced influence on the yield of the target product and the pattern of condensation of 2-methylbenzothiazole with crown-ether benzaldehydes.     

New synthetic approach to epoxyisoindolo[2,1-a]quinolines based on cycloaddition reactions of 2-furyl-substituted tetrahydroquinolines with maleic anhydride and acryloyl chloride

A procedure was developed for the synthesis of hydrogenated furyl-substituted furo[3,2-c]quinolines, pyrano[3,2-c]quinolines, and 4-ethoxy-and 4-(2-oxopyrrolidin-1-yl)quinolines. The reactions of these compounds with acryloyl chloride and maleic anhydride produce epoxyisoindolo[2,1-a]quinoline derivatives through successive acylation at the quinoline nitrogen atom and intramolecular exo-[4+2]-cycloaddition at the furan moiety. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1023–1038, May, 2007.     

Synthesis and halocyclization of 2-alkenylthioquinolines

Bromination of 2-vinylthioquinoline and cis-2-styrylthioquinoline with molecular bromine leads to the formation of 2-bromo(3-phenyl)-2,3-dihydrothiazolo[3,2-a]quinolinium bromides, and of 2-allyl-thioquinoline to a mixture of 2-and 3-bromomethyl-2,3-dihydrothiazolo[3,2-a]quinolinium bromides. Iodine reacts with allylthioquinoline with the formation of 3-iodomethyl-2,3-dihydrothiazolo-[3,2-a]quinolinium triiodide. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1664–1668, November, 2008.     

Some chemical properties of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones

We have studied the reaction of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with amines, alkylating reagents, and hydrogen peroxide. We have shown that the presence of an aryl substituent at the 2 position of [1,3-thiazino[3,2-a]benzimidazol-4-ones has a substantial effect on the direction of the reactions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 445–452, March, 2006.     

Synthesis and reactions of 2-[3-(trifluoromethyl)phenyl]furo[3,2-<Emphasis Type="Italic">c</Emphasis>]pyridine

(E)-3-{5-[3-(Trifluoromethyl)phenyl]furan-2-yl}propenoic acid (I) was prepared from 5-[3-(tri-fluoromethyl)phenyl]furan-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide II, which was cyclized by heating in diphenyl ether to 2-[3-(trifluoromethyl)phenyl]-4,5-dihydrofuro[3,2-c]pyridin-4-one (III). This compound was aromatized with phosphorus oxychloride to chloroderivative IV which was reduced with H₂NNH₂-Pd/C to the title compound V. 2-[3-(Trifluoromethyl)phenyl]furo[3,2-c]pyridin-5-oxide (VI) was synthesized by reaction of V with 3-chloroperoxybenzoic acid in dichloromethane. On treatment of VI with benzoyl chloride and potassium cyanide (Reissert-Henze reaction), corresponding 2-[3-(trifluoromethyl)phenyl]furo[3,2-c]pyridine-1-carbonitrile (VII) resulted. 5-Amino-2-[3-(trifluoromethyl)phenyl]furo[3,2-c]pyridin-5-ium-4-methylbenzene sulfonate (VIII) was prepared by direct N-amination of the title compound V with 1-[(aminooxy)sulfonyl]-4-methylbenzene in dichloromethane. Then, VIII was transformed to a non-isolated zwitterionic N-imid IX which afforded the corresponding furo[3,2-c]pyrazolo[1,5-a]pyridine carboxylic acid esters X, XI by 1,3-dipolar cycloaddition reactions with dimethyl but-2-ynedionate (DBD) or ethyl propiolate. The structures of all compounds were confirmed by their IR and NMR spectra. Presented at the 1st International Conference “Applied Natural Sciences” on the occasion of 10th anniversary of the University of St. Cyril and Methodius, Trnava, 7–9 November 2007.     

Synthesis and Properties of 2-Amino-6-nitroindoles

A new method is proposed for the synthesis of 2-amino-6-nitroindoles, based on the reaction of 2-haloanilines and substituted acetonitriles. The reaction of 2-amino-6-nitroindoles with -dicarbonyl compounds was studied.     

Investigation of the Reactions of Quinolinium Ylide with Nitrostyrenes

The reactions of nitrostyrenes with quinolinium ylide have been investigated. Previously unknown 2-aryl-1-benzoyl-3-nitro-1,2,3,3a-tetrahydropyrrolo[1,2-a]quinolines have been obtained and their stereochemistry has been established.     

A facile synthesis of oxazolo[3,2-a][1,10]phenanthrolines via a new multicomponent reaction

The synthesis of N-cyclohexyl-10-(2-fluorophenyl)-8aH-oxazolo[3,2-a][1,10]phenanthroline and N-(2,6-dimethylphenyl)-10-(2-fluorophenyl)-8aH-oxazolo[3,2-a][1,10]phenanthroline by reaction of 2-fluorobenzaldehyde, phenanthroline and cyclohexyl or 2,6-dimethylphenyl isocyanide is reported.     

Chemistry of Indolopyridines with a Bridgehead Heteroatom. (Review)

Published data on the synthesis and reactions of indolopyridines with one bridgehead heteroatom and their benzannelated derivatives are reviewed for the first time.     

Synthesis of derivatives of a new heterocyclic system, 9-oxo-1,3,4-thiadiazolo[3,2-a]pyrido[3,2-e]pyrimidine

Reaction of 2-substituted 5-imino-7-oxo-1,3,4-thiadiazolo[3,2-a]pyrimidines with pentane-2,4-dione in polyphosphoric acid yields 9-oxo-1,3,4-thiadiazolo[3,2-a]pyrido[3,2-e]pyrimidines.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2037–2038, October, 1995.The authors are grateful to V. A. Dorokhov for the skilled preparation of the paper for publication.     

Synthesis of Functionally Substituted Pyrrolo[2,3-g]- and Pyrrolo[3,2-f]quinolines from 5-Amino-2-phenyl- and 5-Amino-1-methyl-2-phenylindoles

The behavior of 5-amino-2-phenyl- and 5-amino-1-methyl-2-phenylindoles in reactions with acetoacetic, trifluoroacetoacetic, and ethoxymethylenemalonic esters, leading to the preparation of pyrrolo[2,3-g]- and pyrrolo[3,2-f]quinolines with functional substituents has been studied.     

Synthesis of pyrroloquinolines from substituted 6-aminoindoles and oxaloacetic ester

It was established that the initial condensation of substituted 6-aminoindoles and oxaloacetic ester in boiling benzene with the addition of catalytic amounts of acetic acid takes place exclusively through the carboxyl group of the keto ester with the formation of the corresponding enamines, which successfully undergo thermal cyclization (biphenyl, 280°C) to pyrroloquinolines. Here, irrespective of the nature of substituents at the N-1 and C-5 atoms enamines with a free position 7 are transformed into pyrrolo-[2,3-f]quinolines (structural analogs of vitamin PQQ) while 7-OMe-substituted enamines give pyrrolo[3,2-g]quinolines with linear fusion of the rings. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–1002, July, 2008.     

Acylimines of hexafluoroacetone and methyl trifluoropyruvate in cyclocondensation with 2-aminothiazolines

Reactions of acylimines of hexafluoroacetone and methyl trifluoropyruvate with 2-aminothiazolines afforded fluorine-containing heterocycles of two structural types: 6,7-dihydro-2H-thiazolo[3,2-a][1,3,5]triazines and 2,3,5,6-tetrahydroimidazo[2,1-b]thiazoles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1619–1622, July, 2005.     

The reaction of 2-amino-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]-pyrimidine with carbon disulfide and alkylation of its products

In the reaction with carbon disulfide, 2-amino-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine (1) forms the alkaline salts of substituted dithiocarbamic or iminodithiocarbonic acids depending on the molar ratio between1, CS₂, and the alkali. The alkylation of these salts leads to the esters ofN-(7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine-2-yl)dithiocarbamic (2) and diesters of (7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine-2-yl)iminodithiocarbonic acids (3). The synthesis of asymmetric diesters3 may be fulfilled based on monoesters2.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 14–14, August, 1994.     

Formation of the same pyrimido[1,2-a]indoles from 1-(oxiran-2-ylmethyl)-1H-indole or [1,3]oxazolo[3,2-a]indole derivatives in its reactions with aromatic amines

Reactions of two isomers—2-chloro-1-(oxiran-2-ylmethyl)-1H-indole-3-carbaldehyde or 2-(chloromethyl)-2,3-dihydro[1,3]oxazolo[3,2-a]indole-9-carbaldehyde with aromatic amines lead to the same products in both cases—hydrochlorides of pyrimido[1,2-a]indole derivatives containing two fragments of an amine per one part of the indole nucleus. Its structure was confirmed by X-ray analysis of the crystals base, obtained by alkali treatment of the reaction product (when aryl is 4-MeOC₆H₄).