Facile syntheses of 7,9-dimethoxypyrrolo[3,2,1-ij]quinolin-6-ones

The activated dimethoxypyrrolo[3,2,1-ij]quinolin-6-one ring system was synthesized via two approaches, starting from an indole and quinolin-4-one, respectively. Subsequent demethylation led to both monohydroxy- and dihydroxypyrrolo[3,2,1-ij]quinolin-6-ones.     

Palladium(II)-catalyzed heterocyclisation of 8-arylethynyl-1,2,3,4-tetrahydroquinolines: a facile route to 2-aryl-5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline derivatives

Dihydropyrroloquinolines have been synthesized reacting 8-arylethynyl-1,2,3,4-tetrahydroquinolines in the presence of palladium(II) chloride catalyst. Heteroannulation has been achieved in good yields and tolerates substituents on the tetrahydroquinoline, including bromo, cyano, and ester.     

C-N bond forming reaction under copper catalysis: a new synthesis of 2-substituted 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinolines

We report copper-catalyzed intramolecular cyclization of 8-alkynyl-1,2,3,4-tetrahydroquinolines, obtained via a Pd/C-mediated Sonogashira coupling in water, to afford 2-substituted 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinolines. Further functionalization of the compounds synthesized was carried out under Heck, Sonogashira, and Suzuki reaction conditions.     

An Efficient,Microwave-Assisted,One-Pot Synthesis of Dioxolano Quinoline/benzo[h]quinolines as Potent Antibacterial Agents

Quinolines/benzo[h]quinolines are associated with a broad spectrum of biological activities. In view of this, 3-(1,3-dioxolan-2-yl)quinoline/benzo[h]quinoline-2-thiol/selenols were prepared under microwave irradiation through one-pot reactions, and these quinolines/ benzo[h]quinolines were evaluated for potential antibacterial activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of 1H-pyrrolo[3,2-c]quinoline derivatives via palladium-catalyzed heteroannulation of 2-aryl-3-iodo-4-(phenylamino)quinolines and 4-(N,N-allylphenylamino)-2-aryl-3-iodoquinolines

Palladium(0)/copper iodide catalyzed Sonogashira cross-coupling of 2-aryl-3-iodo-4-(phenylamino)quinolines with terminal alkynes afforded series of 1,2,4-trisubstituted 1H-pyrrolo[3,2-c]quinolines in a single-step operation. Conversely, the 4-(N,N-allylphenylamino)-2-aryl-3-iodoquinoline derivatives were found to undergo PdCl₂(PPh₃)₂/CuI catalyzed intramolecular Heck reaction to yield the corresponding 1,3,4-trisubstituted 1H-pyrrolo[3,2-c]quinolines.     

Regioselective Reaction of <Emphasis Type="Italic">N</Emphasis><Superscript>1</Superscript>-Benzyl-<Emphasis Type="Italic">N</Emphasis><Superscript>2</Superscript>-(4-nitrophenyl)ethanediamide and Acetylenic Esters

Summary. The regioselective reaction of N¹-benzyl-N²-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields.     

An Efficient and Convenient Synthesis of 2-Thio[1,2,4]triazolo[1,5-c]quinazoline and its Derivatives

Summary. 4-Hydrazinoquinazoline with carbon disulfide underwent a recyclization reaction. The title compound 2-thio[1,2,4]triazolo[1,5-c]quinazoline was obtained after treatment of 4-hydrazinoquinazoline with potassium ethylxanthogenate via a facile in situ Dimroth-like rearrangement of the expected [4,3-c] system. Its structure was established by X-ray diffraction study and confirmed by an independent synthesis, starting from o-aminobenzonitrile.     

Pyrido[2,3-d]pyrimidines,II. One step synthesis of pyrido[2,3-d]pyrimidines and pyrimido[4,5-b]quinolines from 6-amino uracils

Summary Reduction of 6-azidouracils2 with hydrogen palladium or sodium dithionite afforded the corresponding 6-aminouracils5 which could also be obtained by reaction of2 with triphenylphosphanevia phosphazenes and subsequent hydrolysis (Staudinger reaction). The use of trimethylphosphite instead of phosphanes yields with2b the expected trimethoxyphosphazene3c, whereas2a reacts to the phosphonoaminopyrimidine4. The syntheses of 5-hydroxy pyrido[2,3-d]pryimidine-2,4,7-triones6, pyrido[2,3-d]pyrimidine-2,4,5-triones8, cyclopenta[e]pyrido[2,3-d]pyrimidin-2,4,5-triones7a,c, and tetrahydro-pyrimido[4,5-b]quinolin-2,4,5-triones7b,d by condensation of 6-aminouracils5 with malonates, ethylaceto/benzoylacetate, ethyl 2-oxocyclopentanecarboxylate and ethyl 2-oxocyclohexanecarboxylate, respectively, are described.

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Pyrido[2,3-d]pyrimidine, 2. Mitt. Einstufige Synthese von Pyrido[2,3-d]pyrimidinen und Pyrimido[4,5-b]chinolinen aus 6-Aminouracilen

Zusammenfassung Reduktion der 6-Azidouracile2 mit Wasserstoff/Palladium oder Natriumdithionit ergibt die entsprechenden 6-Aminouracile5, die auch durch Reaktion von2 mit Triphenylphosphin und anschließende Hydrolyse erhalten werden können (Staudinger-Reaktion). Die Verwendung von Trimethylphosphit anstelle von von Trimethylphosphin ergibt mit2b das erwartete Trimethoxyphosphazin3c, während2a zum Phosphonoaminopyrimidin4 reagiert. Die Synthesen der 5-Hydroxy-pyrido[2,3-d]pyrimidin-2,4,7-trione6, der Pyrido[2,3-d]pyrimidin-2,4,5-trione8, der Cyclopenta[e]pyrido[2,3-d]pyrimidin-2,4,5-trione7a,c und der Tetrahydro-pyrimido[4,5-b]chinolin-2,4,5-trione7b,d durch Kondensation der 6-Aminouracile5 mit Malonat, Acetat, Ethyl-2-oxocyclopentancarboxylat und Ethylcyclohexancarboxylat werden beschrieben.

     

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.     

Synthesis of cyclopropa[c]indeno[1,2-b]quinolines through a MCR/Staudinger/aza-Wittig sequence

Spirocyclopropanes were prepared from aromatic aldehydes, 1,3-indandione and acetophenones through a halogenation/S_N2-displacement/Michael-initiated ring-closing sequence by a pyridinium-ylide-assisted multicomponent reaction, and their further use was also researched in the construction of cyclopropa[c]indeno[1,2-b]quinolines through subsequent Staudinger/aza-Wittig reactions.     

A facile synthesis of indolo[3,2,1-jk]carbazoles via palladium-catalyzed intramolecular cyclization

A new efficient synthesis of indolo[3,2,1-jk]carbazoles by the palladium-catalyzed cyclization of N-(2-bromoaryl)carbazoles is described. The reaction involves intramolecular C-C bond formation, coupled with the cleavage of a C-X bond and a C-H bond on carbazole ring. Substitutions on N-aryl core with either electron-donating or electron-withdrawing groups are introduced, and different reaction factors for cyclization are evaluated.     

N-Bromosuccinimide as an efficient catalyst for the synthesis of indolo[2,3-b]quinolines

The use of N-bromosuccinimide as a catalyst promoted the synthesis of polycyclic indolo[2,3-b]quinoline derivatives in good to high yields in the reactions of various aryl amines with indole-3-carbaldehyde at room temperature under mild conditions.     

Synthesis of Fluorinated 1,3,4-Oxadiazino[6,5,4-i,j]quinolines

3-(2-Acylhydrazino)-2-tetra(penta)fluorobenzoylacrylates are readily converted to acylamino-substituted quinolones and, under more forcing conditions, annelation of oxadiazine ring occurs. We have identified the possible cyclization of the mentioned acrylates to 4,5-substituted pyrazoles.     

Synthesis and reactions of 2,3-dimethylfuro[3,2-c]pyridines

Summary A number of substituted 2,3-dimethylfuro[3,2-c]pyridines was synthesized. 3-(4,5-Dimethyl-2-furyl)propenoic acid (1) was converted to the acid azide2, which in turn was cyclized to give 2,3-dimethyl-5H-furo[3,2-c]pyridine-4-one (3) by heating at 240°C in Dowtherm. The pyridone3 was chlorinated with phosphorus oxychloride to give4, which was reduced with zinc and acetic acid to 2,3-dimethylfuro[3,2-c]pyridine (5). Treatment of4 with several secondary heterocyclic amines led to compounds6a–6c. Reaction of pyridone3 with phosphorus pentasulfide rendered the thione7, which was methylated to8a. The 4-methoxy derivative8b was obtained from4 with sodium methoxide. 2,3,5-Trimethylfuro[3,2-c]pyridine-4-one (9) was obtained by reaction of3 with methyl iodide.Dedicated to Professor Dr.Fritz Sauter on the occasion of his 65th birthday     

Synthesis of Functionally Substituted Pyrrolo[3,2-h]quinolines from 2,3-Dimethyl- and 1,2,3-Trimethyl-7-aminoindoles

Methods have been developed for the preparation of several functionally substituted pyrrolo[3,2-h]quinolines via the reaction of 2,3-dimethyl- and 1,2,3-trimethyl-7-aminoindoles with acetoacetic, trifluoroacetoacetic, and ethoxymethylenemalonic esters.     

Synthesis of 2-Aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-Aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones

The reaction of 2-mercaptobenzimidazole, 5-ethoxy-2-mercaptobenzimidazole, and 2-mercaptoimidazoline with cinnamoyl chloride, its derivatives, and heteroanalogs was studied. Convenient methods were found for the synthesis of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones.     

One-pot synthesis of 2-substituted furo[3,2-c]quinolines via tandem coupling-cyclization under Pd/C-copper catalysis

Pd/C-Cu catalyzed coupling reactions of 3-iodo-1H-quinolin-4-ones with a variety of terminal alkynes afforded furo[3,2-c]quinolines regioselectively in good to excellent yields. 3-Alkynyl quinolones were isolated under the same reaction conditions when the nitrogen of 3-iodo-1H-quinolin-4-one was substituted with an alkyl group.     

Synthesis of substituted 4H-thiazolo[4,5-b][1]benzothiopyran-4-ones as possible schistosomicidal agents

Summary Interaction of ethyl 2-acetamido-5-bromothiazole-4-carboxylate (2) with 2-methyl-5-chlorothiophenol (3) afforded the thioether4, which was hydrolysed to the corresponding carboxylic acid5. Attempted cyclization of5 to6 yielded the decarboxylated product7. On the other hand, interaction of 2-acetamido-5-bromothiazole (9) with thiosalicylic acid (10) yielded the thioether11, which was cyclized to compound12. Acid hydrolysis of12 yielded the amino derivative13, which was reacted with certain selected alkyl halides using sodium hydride to afford compounds14–18.

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Synthese von substituierten 4H-Thiazolo[4,5-b][1]benzothiopyran-4-onen als mögliche schistosomicide Wirkstoffe

Zusammenfassung Die Reaktion von Ethyl 2-Acetamido-5-bromthiazol-4-carboxylat (2) mit 2-Methyl-5-chlorthiophenol (3) ergab den Thioether4, der zur entsprechenden Carbonsäure5 hydrolysiert wurde. Die versuchte Cyclisierung von5 zu6 ergab das Decarboxylierungsprodukt7. Andererseits ergab die Reaktion von 2-Acetamido-5-bromthiazol (9) mit Thiosalizylsäure (10) den Thioether11, der zu Verbindung12 cyclisiert werden konnte. Saure Hydrolyse von12 ergab das Aminoderivat13, das mit geeigneten Alkylhalogeniden unter Verwendung von Natriumhydrid zu den Verbindungen14–18 führte.

     

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