Reaction of thieno[2,3-b]pyridines with sodium hypochlorite: An unusual and stereoselective one-pot approach to dimeric pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridines

The oxidation of 3-aminothieno[2,3-b]pyridine-2-carboxamides with commercially available bleach leads to the formation of dimeric pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridines (7a,14a-diamino-7,14-bis(aryl)-7,7a,14,14a-tetrahydro-6H,13H-pyrido[3″″,2″″:4?,5?]thieno[2?,3?:4″,5″]pyrrolo-[3″,4″:3′,4′]pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridine-6,13-diones) in moderate yields (37–52%).     

Microwave-assisted synthesis of fused pyrazolo[3,4-b]pyrazines by the reaction of ortho-aminonitrosopyrazoles and cyclic β-diketones

Novel fused pyrazolo[3,4-b]pyrazines 3 were prepared by assisted microwave cyclocondensation reaction of ortho-aminonitrosopyrazoles 1 and cyclic β-diketones 2 in dimethylformamide. This protocol provides a simple procedure for the synthesis of the title compounds with the advantages of easy work-up, mild reaction conditions and good yields.     

A convenient synthesis of pyrrolo[2,3-b]pyridines and pyrido[2′,3′:5,4]pyrrolo[2,3-d]pyrimidines

2-Chloro-6-ethoxy-4-phenylpyridine-3,5-dicarbonitrile was taken as versatile building block that allows the synthesis of 1H-pyrrolo[2,3-b]pyridine, thieno[2,3-b]pyridine and pyrido[2′,3′:5,4]pyrrolo[2,3-b]pyrimidine systems. Some of the synthesized compounds were screened as antibacterial agents.     

Synthesis of androsteno[17,16-d]pyrazoles and androsteno[17,16-d]-2′-pyrazolines with pyrazolo[3,4-d]pyrimidine fragments

Russian Chemical Bulletin - Reactions of pyrazolo[3,4-d]pyrimidine-containing hydrazines with pregnenolone derivatives were studied. The reaction of...     

Engaging thieno[2,3-b]indole-2,3-dione for the efficient synthesis of spiro[indoline-3,4′-thiopyrano[2,3-b]indole] by reaction with N-substituted isatilidenes

A simple and efficient method, proceeding through a new mechanistic pathway, for the synthesis of spiro[indoline-3,4-thiopyrano[2.3-b]indole derivatives have been developed by exploiting the reaction of thieno[2,3-b]indole-2,3-dione with N-substituted isatilidenes. The compounds synthesized have been screened for antibacterial activity. The generality of the reaction and mechanistic rationale are presented.     

Synthesis of Benzo[4,5]furo[3,2-b]thieno[2,3-d]pyridines —Derivatives of a New Heterocyclic System

Russian Journal of Organic Chemistry - Methyl 2-(bromomethyl)thiophene-3-carboxylates reacted with substituted 2-hydroxybenzonitriles to give methyl...     

Intramolecular Ullmann-type C−N coupling for the synthesis of substituted benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridines

An efficient CuI catalyzed intramolecular Ullmann-type C−N coupling reaction is described here. Newly substituted 1H-benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridine-1,3,5(2H, 11H)-trione has been easily synthesized from ortho halogenated N-substituted pyrrolo[3,4-c]pyridine-1,3,6(5H)-triones in presence of CuI catalyst and K₂CO₃ base without any ligand. This procedure is based on intramolecular Ullmann-type reaction and provides a proficient method of making fused tetracyclic heterocycles.     

Mild and efficient Winterfeldt oxidation of 1,2,3,4-tetrahydro-γ-carbolines for the synthesis of dihydropyrrolo[3,2-b]-quinolones and pyrrolo[3,2-b]quinolones

The Winterfeldt oxidation (NaOH, DMF, air, rt) of substituted 1,2,3,4-tetrahydro-γ-carbolines has been developed, which provides a convenient and efficient method for the synthesis of the corresponding dihydropyrrolo[3,2-b]quinolones in moderate to excellent yields (38-94%). The generality and substrate scope of this reaction are explored and a possible mechanism is proposed. The results imply that electron-withdrawing groups on N2 of tetrahydro-γ-carbolines and N5-H are necessary. The synthesis of 5 or 7-substituted pyrrolo[3,2-b]quinolones in near quantitative yields was also achieved through deprotection and aromatization of N1-Boc-dihydropyrrolo[3,2-b]quinolones.     

Pyrido[2,3-d]dipyrimidines 8. Synthesis of pyrrolo(2′,3′∶4,5)pyrido[2,3-d]pyrimidines

The reaction of 1,3-dimethyl-5-chloro-6-nitropyrido[2,3-d]pyrimidine-2,4-dione with CH-acids yielded 5-substituted pyridol[2,3-d]pyrimidines which were used in the synthesis of pyrrolo(2,34,5)pyrido[2,3-d]pyrimidines.For Communication 7, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 800–803, June, 1993.     

Synthesis of 2,4-disubstituted pyrimido[4,5-b]-indoles,pyrano[4′,3′:4,5]pyrrolo[2,3-d]pyrimidines and some conversions of pyrimido[4,5-d]indoles

Methods have been developed for the production of 2,4-disubstituted 5,6,7,8-tetrahydro-9H-pyrimido[4,5-b]indoles and pyrano[43:4,5]pyrrolo[2,3-d]pyrimidines. Heterocyclization reactions were carried out on 4-hydrazinopyrimido[4,5-b]indoles.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan, 375014. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10. pp. 1413–1416, October, 1996. Original article submitted June 21, 1996.     

Intramolecular palladium-catalysed enolate arylation of 2- and 3-iodoindole derivatives for the synthesis of β-carbolines, γ-carbolines, and pyrrolo[3,4-b]indoles

The palladium-catalysed intramolecular α-arylation of carbonyl compounds with amino-tethered 2- and 3-iodoindoles provides a useful methodology for the synthesis of indolo-b-fused nitrogen heterocycles. A variety of substituted tetrahydro β- and γ-carbolines, and pyrrolo[3,4-b]indoles, have been prepared by means of this palladium-catalysed annulation process.     

Synthesis of Some New Thieno[2,3-b]pyridines,Pyrimidino[4′,5′:4,5]thieno[2,3-b]-pyridines,and 2,3-Dihydro-1,3,4-thiadiazoles

Thieno[2,3-b]pyridines were synthesized from 6-benzofuran-2-yl-4-phenyl-2-sulfanylpyridine-3-carbonitrile and each of chloro acetone, ethyl chloroacetate, ω -bromoacetophenone, and chloroacetonitrile. These compounds were conveniently converted into novel pyrido[4′,5′:4,5]thieno[3,2-d]pyrimidines. Also, 2,3-dihydro-1,3,4-thiadiazole was synthesized from hydrazonoyl halides and 2-benzofuran-2-yl-3-(phenylamino)-3-thioxopropanenitrile. The structures of the products have been elucidated by elemental analyses, spectral data studies, and alternative syntheses whenever possible. The newly synthesized compounds were tested towards microorganisms.     

Synthesis and characterization of some new pyridines,thieno[2,3-b] pyridines and pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine-4(3H)-ones bearing styryl moiety

3-Cyano-5-ethoxycarbonyl-6-methyl-4-styrylpyridine-2(1H)-thione ( 3 ) was prepared by reaction of 2-cyano-5-phenylpenta-2,4-dienethioamide ( 2 ) with ethyl acetoacetate or by multicomponent reaction of cinnamaldehyde ( 1 ), cyanothioacetamide and ethyl acetoacetate in a moderate yield. Reaction of compound 3 with some N-aryl-2-chloroacetamides, in the presence of sodium acetate, gave the corresponding 2-(N-arylcarbamoylmethylsulfanyl)-3-cyano-5-ethoxycarbonyl-6-methyl-4-styrylpyridines 4a-f . When compounds 4a-f were subjected to Thorpe-Ziegler reaction conditions, they converted into the corresponding 3-amino-5-ethoxycarbonyl-2-(N-arylcarbamoyl)-6-methyl-4-styrylthieno[2,3-b]pyridines 5a-f . Compounds 5a,e,f were reacted, in turn, with 2,5-dimethoxytetrahydrofuran to furnish the corresponding 3-(pyrrol-1-yl)thieno-pyridines 6a,e,f . Reactions of 5a-f with triethyl orthoformate or nitrous acid were also carried out and their products were identified. Structural formulas of all synthesized compounds was characterized and confirmed on the basis of their elemental and spectral analyses.     

Functionalization of α-Aminonicotinonitrile: A New Entry for Synthesis of Pyrazolo[3,4-b]pyridine,Pyrido[2,3-d]pyrimidine,and 1,8-Naphthyridine Derivatives

Russian Journal of General Chemistry - Functionalization of α-aminopyridine to a new series of pyridine and fused pyridine derivatives has been achieved via its reaction with a variety of...     

Synthesis of benzothieno[2,3-b]thiophenes, [2,3-b:3′,2′-d]-dithienothiophenes and their selenium derivatives via electrophilic cyclization and McMurry cyclization

Benzothieno[2,3-b]thiophenes, [2,3-b:3′,2′-d]-dithienothiophenes, and their selenium derivatives were synthesized in good yields from readily available 3-ethynyllithio-benzo[b]thiophenyllithio compounds, sulfur or selenium, and 2 equiv of acid chlorides. Two heteroarene rings were constructed by a twofold cyclization via an acid chloride-induced electrophilic ring closing and the McMurry cyclization using Zn/TiCl₄ reagents.     

Synthesis of Angular [1,2,5]Oxadiazolo[3,4-b]pyrazino-[1′,2′ : 1,2]pyrrolo[2,3-e][1,4]diazepine by Stepwise Reaction of Pyrrolo[1,2-a]pyrazinetrione with 3,4-Diaminofurazan

Russian Journal of Organic Chemistry - Diaminofurazan reacted with 8-benzoyl-2-phenyl-3,4-dihydropyrrolo[1,2-a]pyrazine-1,6,7(2H)- trione to give addition product of the amino group to the double...     

New multicomponent domino reaction on water: highly diastereoselective synthesis of spiro[indoline-3,4′-pyrazolo[3,4-b]pyridines] catalyzed by NaCl

A direct and efficient approach for the preparation of medicinally promising pyrazolopyridinyl spirooxindoles has been developed through a sequential one-pot, three-component reaction of easily available isatin, α-cyanoacetic ester or malononitrile, and 5-amino-3-methylpyrazole catalyzed by sodium chloride in water. Desired products were obtained in high to excellent yields using a simple workup procedure. The product synthesized using α-cyanoacetic ester showed high diastereoselectivity in which the stereochemistry of major diastereomer was confirmed by X-ray diffraction analysis. The present green synthesis shows attractive characteristics such as the use of water as the reaction medium, one pot conditions, short reaction period, easy workup/purification, and reduced waste production, without use of any acid or metal promoters.     

Using magnetized water as a solvent for a green,catalyst-free,and efficient protocol for the synthesis of pyrano[2,3-c]pyrazoles and pyrano[4′,3′:5,6]pyrazolo [2,3-d]pyrimidines

Research on Chemical Intermediates - A facile, eco-friendly, and highly efficient one-pot four-component protocol is demonstrated for the synthesis of the pyrano[2,3-c]pyrazole and...     

Synthesis of Certain 3-Aminopyrazolo[5,4-b]pyridine and 3,4-Substituted Pyrido[2′,3′：3,4]pyrazolo[5,1-c][1,2,4]triazine Derivatives

2-Thioxo-1,2-dihydropyridine derivatives 2a, 2b were reacted with methyl iodide to give 2-methylthiopyridines 3a, 3b, which were reacted with hydrazine hydrate to produce 3-aminopyrazolo[5,4-b]pyridines 4a, 4b. Compounds 4a, 4b were diazotized to afford the corresponding diazonium salts 5a, 5b, which were reacted with some active methylene compounds 6a-6h to give the corresponding pyrido[2′,3′ ： 3,4]pyrazole[5,1-c][1,2,4]triazines 7-14.