Heterocyclic Quinones in the Nenitzescu Reaction. Synthesis of Furo- and Pyrrolobenzothiazoles from 2-Methyl-4,7-dioxobenzothiazole

Treatment of the enamines of acetylacetone and benzoylacetone with 2-methyl-4,7-dioxobenzothiazole under Nenitzescu reaction conditions gave furo[2,3-e]benzothiazoles (in acetic acid) and pyrrolo[2,3-e]benzothiazoles (in nitromethane). Using enamines of acetoacetic ester gave exclusively pyrrolo[2,3-e]benzothiazoles.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 252–258, February, 2005.     

Synthesis of pyrrolo[2,3-g]-and pyrrolo[3,2-f]quinolines from 5-amino-2,3-dimethyl-and 1,2,3-trimethylindoles with 4,4,4-trifluoroacetoacetic ester

It has been shown that the condensation reaction of 5-amino-2,3-dimethyl-and 1,2,3-trimethylindoles with 4,4,4-trifluoroacetoacetic ester occurs either via the trifluoromethylcarbonyl or the ester group depending upon the conditions under which it is carried out. Under thermal conditions (refluxing in diphenyl) the enaminocrotonates formed are readily converted to pyrrolo[3,2-f]quinolines and the amides cyclize in trifluoroacetic acid at 78°C to give pyrrolo[2,3-g]quinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 86–96, January, 2006.     

The potential use of 6-amino-5-methoxy(methyl)-2,3-dimethyl-and 6-amino-5-methoxy(methyl)-1,2,3-trimethyl-indoles in the synthesis of pyrrolo[2,3-f]quinolines

The reaction of 6-amino-2,3-dimethyl-and 6-amino-1,2,3-trimethyl-5-methoxy(methyl)indoles with 4,4,4-trifluoroacetoacetic ester and of 6-amino-5-methoxy-1,2,3-trimethylindole also with other β-dicarbonyl compounds has been studied. It was found that all of the amines investigated undergo condensation readily to form the corresponding enamines while the possible subsequent cyclization to give pyrrolo[2,3-f]quinolines was found only for the condensation product of 6-amino-2,3,5-trimethylindole with 4,4,4-trifluoroacetoacetic ester. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp 97–103, January, 2006.     

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 Functionally Substituted Pyrrolo[3,2-<Emphasis Type="Italic">g</Emphasis>]quinolines from 6-Amino-7-methoxy-1,2,3-trimethylindole

The comparative reactivities of 6-amino-1,2,3-trimethyl- and 6-amino-7-methoxy-2,3-dimethylindoles with acetylacetone, dibenzoylmethane, and with aceto- and trifluoroacetoacetic esters have been studied. Methods have been developed for the preparation of some functionally substituted pyrrolo-[3,2-g]quinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1529–1539, October, 2005.     

Inverse-electron-demanddiels-alder reactions of condensed pyridazines VI: Ring transformations of pyrido[2,3-d]pyridazine intog-fused quinolines

Summary A series ofg-annelated quinolines was synthesized, employing pyrido[2,3-d]pyridazine as an azadiene in inverse-electron-demandDiels-Alder reactions with electron-rich dienophiles (enamines and a ketene-N,S-acetal). In cases where isomer mixtures were obtained, NOE difference spectroscopy was used for structural assignment.Dedicated with best wishes to Prof. Dr. F. Sauter on the occasion of his 65^th birthday     

Novel heterocyclic systems based on 8-R-4,5-dihydro-4,4-dimethyl-[1,2]dithiolo[3,4-c]quinoline-1-thiones

Based on the reaction of 8-R-4,5-dihydro-4,4-dimethyl[1,2]dithiolo[3,4-c]quinoline-1-thiones with oxalyl chloride followed by the reactions of 1,3-dipolar cycloaddition and diene synthesis with participation of acetylenedicarboxylic acid dimethyl ester, we have developed approaches to synthesis of novel polycondensed heterocyclic systems: [1,2]dithiolo[3,4-c]pyrrolo[3,2,1-ij]quinoline-4,5-dione, 6-(1,3-dithiol-2-ylidene)-1,2-dioxo-5-thioxo-7H-pyrrolo[3,2,1-ij]quinoline and 4,5-dioxospiro(pyrrolo)-[3,2,1-ij]thiopyrano[2,3-c]quinoline-11,2′-[1,3]dithiole. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 610–615, April, 2006.     

Enamines of the 1,2,3,4-tetrahydroiso-quinoline series in the Chichibabin synthesis of pyrrolo[2,1-a]isoquinolines and in reaction with oxalyl chloride

It has been shown that the Chichibabin reaction of enamines of the 1,2,3,4-tetrahydroisoquinoline series and 1,2,3,4-tetrahydrobenzo[f]isoquinoline series with p-bromophenacyl bromide leads to pyrrolo[2,1-a]isoquinoline derivatives. The same heterocyclic system is obtained on interaction of 1-alkyl-3,4-dihydroisoquinolines or their benzo[f]-analogs with oxalyl chloride. The obtained dioxopyrrolines form derivatives of benzo[g]quinoxalino[2,3-b]indolizine on condensation with o-phenylenediamine. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1068–1074, July, 2007.     

The investigations in 2,3′-biquinoline series. 25*. Synthesis of 4-(2-quinolinyl)-pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinolines and 4-(2-quinolyl)-imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinolines

A method has been developed for the synthesis of 4-(2-quinolinyl)-1,2,3,3a-tetrahydropyrrolo-[1,2-a]quinolines based on the 1,3-dipolar cycloaddition reaction of α,β-unsaturated carbonyl compounds to 2,3′-biquinolinium salts. Oxidation in benzene using MnO₂ gave 4-(2-quinolinyl)-pyrrolo[1,2-a]quinolines. It was found that a side product of the 1,3-dipolar cycloaddition is 7,14-di-benzoyl-6,13-di(2-quinolyl)-6a,7,13a,14-tetrahydro-7a,14a-diazadibenzo[a,h]anthracene. Reaction of 1′-phenacyl-2,3′-biquinolinium salts with hydroxylamine in acetic acid gave 4-(2-quinolyl)imidazo-[1,2-a]quinolines. *For Communication 24 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 433–439, March, 2009.     

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 and spectral properties of substituted 4-chlorooxazoloquinolines

Summary The treatment of a mixture of linearly and angularly annelated 2-substituted oxazolo[4,5-f]quinolones (5a–c) and oxazolo[5,4-g]quinolones (6a–c) and similarly the treatment of 2-substituted oxazolo[5,4-f]quinolones (7a–c) and oxazolo[4,5-g]quinolones (8b,c) with POCl₃ afforded substituted 4-chlorooxazolo[4,5-f]quinolines (9a–c) and 2-substituted 4-chlorooxazolo[5,4-f]quinolines (10b,c), respectively. Spectral characteristics of the synthesized derivatives (¹H and¹³C NMR, IR, UV, and MS) are discussed.Dedicated to Prof.Fritz Sauter on the occasion of his 65th birthday     

Synthesis of 4b,5,10a,11-tetrahydroindeno[1,2-b]quinolin-10-ones from Baylis-Hillman adducts

We developed an efficient synthetic method for indenoquinoline skeletons from Baylis-Hillman adducts. 4b,5,10a,11-Tetrahydroindeno[1,2-b]quinolin-10-ones and 7H-indeno[2,1-c]quinolines were prepared from Baylis-Hillman adducts in polyphosphoric acid.     

Synthesis of pyrrolo[2,3-<Emphasis Type="Italic">H</Emphasis>]quinolines from 4-amino-2,3-dimethyl-and 4-amino-1,2,3-trimethylindoles

A study was carried out on the reactions of 4-amino-2,3-dimethyl-and 4-amino-1,2,3-trimethylindoles with acetylacetone, dibenzoylmethane, ethyl acetoacetate, ethyl trifluoroacetoacetate, and ethyl oxaloacetate. Methods were developed for the synthesis of a series of substituted pyrrolo-[2,3-h]quinolines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1234–1242, August, 2007.     

Synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines via intramolecular aza Diels-Alder reaction

An efficient and convenient one-pot intramolecular aza Diels-Alder approach for the synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines has been reported. Particularly valuable features of this methodology include simple execution, inexpensive catalyst, and good product yields.     

Heterocyclic Quinones in ihe Nenitzescu Reaction. Synthesis of Furo- And Pyrroloquinolines from 2-Methoxycarbonyl-4-oxo-5,8-quinolinequinone

Derivatives of furo[2,3-f]quinoline were synthesized by the reaction of the enamines of acetylacetone and benzoylacetone with 2-methoxycarbonyl-4-oxo-5,8-quinolinequinone. A derivative of pyrrolo[2,3-h]quinoline was obtained from N-benzyl--aminocrotonic ester.     

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.     

2,2,4-Trimethylhydroquinolines in the Bischler-Melau Reaction

8-R-1-Aryl-4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinolines have been synthesized by the Bischler-Melau reaction in the series of 6-R-2,2,4-trimethylhydroquinolines.     

Effect of the trifluoroacetyl group on the direction of the recyclization of the pyrazine ring in 6-trifluoroacetylpyrrolo[1,2-a]pyrazinium salts

A cyclotransformation of 6-trifluoroacetylpyrrolo[1,2-a]pyrazinium salts involving the trifluoroacetyl group carbon atom was discovered and investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1714–1719, November, 2007.     

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.     

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.