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 New Derivatives Benzo[4′,5′]imidazo[2′,1′:6,1]pyrido[2,3-d]pyrimidine

Russian Journal of Organic Chemistry - The reactions of 4-methyl- and (RS)-4,6-dimethyl-2-phenyl-5,6-dihydrobenzo[4′,5′]imidazo-[2′,1′:6,1]pyrido[2,3-d]pyrimidines and...     

Alkylation of pyrimido[5′,4′:5,6]pyrido[3,2-b]indol-4-one derivatives

Alkylation of 11-benzyl-3,11-dihydro-4H-pyrimido[5′,4′:5,6]pyrido[3,2-b]indol-4-one with methyl iodide and methyl bromoacetate in DMF gave 3-alkylpyrimidopyridoindolones as the corresponding salts. The reaction in acetone in the presence of K₂CO₃ yielded 3,6-disubstitution products. Alkylation with DMF dimethyl acetal gave a mixture of the 3- and 6-alkylpyrimidopyridoindol-4-one bases. The structure of 4-oxo-4,6-dihydro-3H-pyrimido-[5′,4′:5,6]pyrido[3,2-b]indol-11-ium chloride (3b) was proved by X-ray diffraction analysis.     

A general route for the synthesis of pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine derivatives

Summary A facile synthesis of 8-substituted pyrimido[4,5:4,5]thieno[2,3-c]pyridazines (6a–i) has been accomplished. The sequence involves the ring closure of a heterocyclic aminonitrile precursor (3) after reaction with (dichloromethylene)-dimethylammonium chloride.

---

Eine allgemeine Synthese von Pyrimido[4,5:4,5]thieno[2,3-c]pyridazin-Derivaten

Zusammenfassung Es wurde ein einfacher Syntheseweg für 8-substituierte Pyrimido[4,5:4,5]thieno-[2,3-c]pyridazine entwickelt. Die Reaktion verläuft über den Ringschluß eines heterocyclischen Aminonitrilvorläufers (3) nach Umsetzung mit Dichlormethylen-dimethylammoniumchlorid.

     

Novel ionic liquid–mediated approach for the synthesis of tetracyclic[6,5,5,5]indole ring

A novel acidic ionic liquid–catalyzed protocol for the synthesis of diversely substituted tetracyclic indole core has been devised. The application of ionic liquid provides this methodology with various merits over conventional methods regarding reaction time, yield, and ease of handling. Acidic ionic liquid has been employed as a catalytic agent in this protocol.     

Efficient one-pot synthesis of some new pyrimido[5′,4′:5,6]pyrido[2,3-d]pyrimidines catalyzed by magnetically recyclable Fe3O4 nanoparticles

The study is devoted to one-pot reaction of 1,3-dimethylbarbituric acid with aromatic aldehydes and ammonium acetate using Fe₃O₄ nanoparticles as efficient and magnetically recyclable catalysts. Aromatic aldehydes substituted with electron-withdrawing groups or none, reacted successfully with 1,3-dimethylbarbituric acid and ammonium acetate to give new pyrimido[5′,4′:5,6]pyrido[2,3-d]pyrimidine derivatives (can be also named as pyrido[2,3-d:6,5-d′]dipyrimidines) in high yields over relatively short reaction time. The Knoevenagel condensation products were isolated using aromatic aldehydes bearing electron-donating substituents. The catalyst could be efficiently used for four times without substantial reduction in its activity. The new products were characterized on the basis of FT-IR, ¹H NMR and ¹³C NMR spectral data.

     

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.     

Pyridazines,LIV: On the synthesis of pyridazine-fused S-heterocycles: Thieno[2,3-c]pyridazine,pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine,and pyridazino[3,4-b][1,4]benzothiazine

Summary Starting from 3-chloro-4-pyridazinecarbonitrile (1), the thienopyridazine derivatives2 and3 were prepared. Condensation of3 with triethyl orthoformate afforded the novel tricyclic system4. Reaction of1 with 2-aminothiophenol, followed by treatment with NaH/DMSO was found to give the diaza-phenothiazine6 instead of the expected condensed thiazepine.Dedicated with best wishes to Prof. Dr. G. Zigeuner on the occasion of his 70^th anniversary     

Tautomerization of pyrido[2′,1′:2,3]imidazo[4,5-B]quinoline-12-ylcyanide: A DFT study

The titled imidazo compound can exist as three tautomers: OH, CH, and NH forms. Firstly, the OH tautomer is produced, which can be tautomerized to the CH and NH tautomers via the intramolecularproton transfer. Herein, employing density functional theory and handling the solvent effects with the PCM model, the structural parameters, energy behavior, and also tautomerization mechanism of the tautomers are investigated. Based on the DFT results and the obtained-AIM parameters, the CH tautomer is considered to be the most stable one. Also, the CH tautomer is a kinetically and thermodynamically controlled product in tautomerization of the OH tautomer in a methanol solution.     

Regioselective synthesis of novel imidazo[1,5-b]pyridazine derivatives from diaminoimidazoles and α-acylacrylonitriles

The heterocyclization of 1,2-diamino-4H-phenylimidazole with α-acylacrylonitriles affords cleanly 7-amino-2-R-5- phenylimidazo[1,5-b]pyridazine-3-carbonitriles. The strating α-acylacrylonitriles can be generated in situ from 3-oxo-3-(het)arylpropanenitriles and triethylorthoformate or dimethylformamide dimethyl acetal, and the products can be prepared in one pot.     

3-Aminothieno[2,3-b]pyridine-2-carboxylate: Effective precursor for microwave-assisted three components synthesis of new pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one hybrids

In this study, ethyl 3-aminothieno[2,3-b]pyridine-2-carboxylate was taken as a versatile precursor for the one-pot three-component synthesis of related fused pyrimidine hybrids. The tandem protocol involved the reaction of 3-aminothieno[2,3-b]pyridine, dimethylformamide-dimethylacetal, and amines. The reaction afforded a new series of the target pyrimidine hybrids, linked to different arene units, in good to excellent yields. The prior reaction was evaluated in different solvents under traditional heating or microwave irradiation. Moreover, the influence of reaction temperature was also examined. The optimal conditions were obtained under microwave irradiation in dioxane at 110°C for 40 to 60 min. Additionally, by repeating the previous tandem reaction using the appropriate amines at reaction times of 20 to 60 min, a new series of pyrimidine hybrids linked to alkyl, arylthiazole, and benzo[d]thiazole units has been prepared in good to excellent yields. Furthermore, the utility of bis(amines) was examined to conduct the synthesis of new bis(pyrimidine) hybrids linked to aliphatic cores, in excellent yields, using the same protocol at 30 min reaction time.     

Synthesis of novel spiro-fused pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidines

New pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidines, with an associated spiro-3,3′-oxindole attachment, were prepared by three-component combinations of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione with a pair of reactants chosen from a pyrazol-5-one, a pyrazole-5-amine, a barbituric acid, or a 6-aminouracil.     

Condensed pyridopyrimidines. 1. Synthesis of new derivatives of pyrano[3′,4′∶5,6]pyrido[2,3-d]pyrimidines

New derivatives of pyrano[3,45,6]pyrido[2,3-d]pyrimidines were synthesized from ethyl 2-amino-7,7-dimethyl-7,8-dihydro-5H-pyrano[4,3-b]pyridine-3-carboxylate.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1239–1241, September, 1999.     

A one-pot,three-component synthesis of spiro[indoline-isoxazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine]triones in water

A one-pot, three-component condensation reaction of an isatin, isoxazole, and barbituric acid in water to give spirooxindoles in high yields, at 70 °C temperature, using a catalytic amount of p-toluene sulfonic acid, is described.     

Green metal-free synthesis of spiro-fused 3,4′-pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives via deamination cyclization reactions in aqueous medium

Research on Chemical Intermediates - A green metal-free synthesis of spiro-fused 3,4′-pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives via deamination cyclization reactions...     

Five-membered 2,3-dioxoheterocycles: XCIV. Recyclization of 4,5-diaroyl-1H-pyrrole-2,3-diones under the action of 3-aminopyrazolo[3,4-b]pyridine. Crystal and molecular structure of substituted pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine

1-Aryl-4,5-diaroyl-1H-pyrrole-2,3-diones react with 3-amino-4,6-dimethyl-2H-pyrazolo[3,4-b]-pyridine affording N-aryl-2,3-diaroyl-8,10-dimethylpyrido [2′,3′:3,4]pyrazolo[1,5-a]pyrimidine-4-carboxamides.     

New approaches to the synthesis of functionally substituted pyrido[3′,2′:4,5]thieno[3,2-b]pyridines and the structure of the products obtained

Substituted pyrido,[3',2':4,5]thieno[3,2-b]pyndines were obtained by the reaction of 3-amino-2-benzoylthieno [2,3-b]pyridines with malononitrile and the reaction of 3-cyanopyridine-2(IH)-thiones with 2-aryl-3-bromo-I,I-dicyanopropene. 2-Amino-4-(4-bromophenyl)-7, 9-dimethyl-3-cyanopyrido [3',2':4,5]thieno[3, 2-b]-pyridine was used for the synthesis of a derivative of pyrido[3",2":4', 5']thieno[2',3':5,6]pyrido[2,3-d]-pyrimidine. The structure of these compounds was confirmed by spectral data and x-ray diffraction structural analysis.Deceased.