Synthesis of derivatives of pyrido[3′,2′:4,5]furo[3,2-c]isoquinoline heterocyclic system

An approach to the synthesis of derivatives of new heterocyclic system, pyrido[3′,2′:4,5]-furo[3,2-c]isoquinoline, was suggested. A condensation reaction of substituted 3-cyanopyridin-2(1H)-ones with methyl 2-(chloromethyl)benzoate and subsequent treatment of the condensation product with potassium tert-butoxide leads to substituted pyrido[3′,2′:4,5]furo[3,2-c]-isoquinolin-5(6H)-ones. Similarly, a condensation reaction of substituted 3-cyanopyridin-2(1H)-ones with 2-(chloromethyl)benzonitrile and subsequent treatment of the condensation product with potassium tert-butoxide gives substituted 5-aminopyrido[3′,2′:4,5]furo[3,2-c]-isoquinolines.     

Synthesis of pyrido[3′,2′:4,5]thieno[2,3-c]cinnolines — A new heterocyclic system

Pyrido[3,2:4,5]thieno[2,3-c]cinnolines, new heterocyclic compounds, were obtained in three steps: 1) alkylation of 3-cyanopyridine-2(1H)-thiones by o-nitrobenzyl bromide to give 2-(o-nitrobenzyl)thio-3-cyanopyridines, 2) closure of the thiophene ring in these intermediates to give 3-amino-2-(o-nitrophenyl)thieno[2,3-b]pyridines, and 3) closure of the pyridazine ring by condensation of the amino and nitro groups in triethyl phosphite, leading to the final heterocyclic system.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 104–109, January, 1998.     

Synthesis,photophysical and antioxidant properties of pyrrolo[3,2-c]carbazole and dipyrrolo[3,2-c:2′,3′-g]carbazole compounds

Research on Chemical Intermediates - The synthesis of (6-ethyl-1,6-dihydropyrrolo[3,2-c]carbazol-2-yl)methanol 5 and...     

Copper-catalyzed synthesis of 3-substituted-5-amino-1,2,4-thiadiazoles via intramolecular N–S bond formation

A copper-catalyzed N–S bond formation was utilized to produce 3-substituted-5-amino-1,2,4-thiadiazoles from imidoyl thioureas obtained by reaction of amidine hydrochlorides with isothiocyanates. Moreover, the 1,2,4-thiadiazoles were generated through a one-pot protocol without the isolation of the intermediates. This new method is highly efficient and convenient because it employs the cheap and environmentally friendly copper salt and can be conducted under air.     

Urea mediated 5-substituted-1H-tetrazole via [3 + 2] cycloaddition of nitriles and sodium azide

A simple, new and convenient metal free procedure for the synthesis of 5-substituted 1H-tetrazoles using various nitriles and sodium azide in the presence of urea and acetic acid with good to high yields is developed. The reaction plausibly proceeds through in situ formation of urea azide active complex without toxic and/or expensive metal catalysts.     

Synthesis of substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-ones and their sulfinyl and sulfonyl derivatives

A method for the synthesis of previously unknown pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-ones was suggested, which includes a condensation reaction of substituted 3-cyanopyridine-2(1H)-thiones with methyl 2-(chloromethyl)benzoate and subsequent treatment of the condensation products with potassium tert-butoxide. The oxidation of the condensation products to sulfoxides or sulfones and subsequent treatment of these compounds with potassium tert-butoxide led to substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-one 11-oxides or substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-one 11,11-dioxides.

     

Construction,characterization, and antimicrobial evaluation of the novel heteroannulated chromeno[2′′,3′′:6′,5′]pyrido[2′,3′-d] [1,3] thiazolo[3,2-a]pyrimidines

The reaction of chromone-3-carbonitrile with thiobarbituric acid afforded 2-thioxochromeno[3′,2′:5,6]pyrido[2,3-d]pyrimidine-4,6(1H,3H)-dione, which utilized as a building block for construction of a novel heteroannulated compounds containing chromenopyridothiazolopyrimidine moiety. Reactions of the starting compound with a variety of bielectrophilic reagents namely; chloroacetonitrile, bromomalononitrile, 3-chloropentanedione, ethyl 2-chloro-3-oxobutanoate, phenacyl bromide, chloroacetic acid, dibromoethane, and oxalyl chloride afforded the first known chromenopyridothiazolopyrimidines. Cyclization of the starting compound with 2,3-dichloroquinoxaline gave the linear hepta-annulated chromenopyridopyrimidothiazoloquinoxaline. In addition, chromenopyridopyrimido thiazolopyrimidines were efficiently synthesized. The antimicrobial activity was evaluated for the prepared compounds and some of them seemed notable activity against the tested microorganisms. Analytical and spectral data confirmed the structures of the new products.     

[6π+4π] Cycloadditions of 5-azoniafulvene ions with nitrones and azomethine imines.

Nitrones as well as azomethine imines generated by the prototropic route from hydrazones are shown to add readily to the title iminium ions to give pyrrolo-annellated oxadiazine and triazine derivatives.     

Synthesis of new pyrido[2′,3′:3,4]pyrazolo[5,1-c]-[1,2,4]triazin-4(6H)-one derivatives

Russian Chemical Bulletin - New pyrido[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one derivatives were synthesized from accessible 1,2,4-triazine and pyrazolo[5,1-c][1,2,4]triazine...     

Facile synthesis and characterization of novel pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one and pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine incorporating 1,3-diarylpyrazole moiety

4-(3-(4-Hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-6-phenyl-2-thioxo-1,2-di hydro-pyridine-3-carbonitrile (1) reacted with ethyl chloroacetate (2) in ethanolic sodium acetate solution to yield the corresponding ethyl (3-cyanopyridin-2-ylsulphanyl)acetate derivative 3. Intramolecular cyclization of compound 3 was achieved by its heating in DMF containing potassium carbonate to afford the corresponding ethyl 3-aminothieno[2,3-b]pyridine-2-carboxylate derivative 4 which reacted with hydrazine hydrate in refluxing pyridine to yield the starting material 3-aminothieno[2,3-b]pyridine-2-carbohydrazide derivative 7. Compound 7 reacted with different reagents such as triethylorthoformate, formic acid, acetic acid and acetic anhydride to afford the target molecules pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one derivatives 8–10, 12 and 13 in good to excellent yields. On the other hand, pyridine-2(1H)-thione derivative 1 reacted with hydrazine hydrate in refluxing pyridine to give the other starting material 3-amino-1H-pyrazolo[3,4-b]pyridine derivative 20 which reacted with acetylacetone under reflux to afford the target molecule pyrido[2′,3′:3,4]pyrazolo[1,5-a]-pyrimidine derivative 21 in a good yield. The structures of target molecules were elucidated using elemental analyses and spectral data.     

Synthesis and reactions of new 4-chloro-2-methylpyrimidino[4′,5′:4,5]thiazolo[3,2-a]-benzimidazoles

Summary 4-Chloro-2-methylpyrimidino[4,5:4,5]thiazolo[3,2-a]benzimidazole (3) was prepared by chlorination of2 which could also be converted directly to 2-methylpyrimidino[4,5:4,5]-thiazolo[3,2-a]benzimidazol-4-thiol (4). Nucleophilic substitution of3 with alcohols, phenols, primary amines, secondary amines, sodium azide, and mercaptoacetic acid gave the corresponding derivatives. The thiol derivative4 was reacted with alkyl/aralkyl halides, phenacyl bromide derivatives, bromoacetone, chloroanilides, bromomalonic ester, and ethyl bromoacetate to afford compounds of potential pharmacological interest.

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Synthese und Reaktionen neuer 4-Chlor-2-methylpyrimidino[4,5:4,5]thiazolo[3,2-a]benzimidazole

Zusammenfassung 4-Chlor-2-methylpyrimidino[4,5:4,5]thiazolo[3,2-a]benzimidazol (3) wurde durch Chlorierung von2, welches auch direkt zu 2-Methylpyrimidino[4,5:5,4]thiazolo[3,2-a]-benzimidazol-4-thiol (4) umgesetzt werden kann, hergestellt. Nucleophile Substitution von3 mit Alkoholen, Phenolen, primären Aminen, sekundären Aminen, Natriumazid und Mercaptoessigsäure ergab die entsprechenden Derivate. Das Thiolderivat4 wurde mit Alkyl/Alkarylhalogeniden, Phenacylbromidderivaten, Bromaceton, Chloraniliden, Brommalonsäureester und Bromessigsäureethylester zu potentiell pharmakologisch interessanten Verbindungen umgesetzt.

     

A new convenient four-component synthesis of 6-amino-2H, 4H-pyrano[2,3-c]pyrazole-5-carbonitriles and one-pot synthesis of 6 ′-amino-5-cyano-1,2-dihydrospiro-[(3H)-indole-3,4 ′-(4 ′H)-pyrano[2,3-c]pyrazol]-2-ones

A new convenient method for the synthesis of 6-amino-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitriles, namely, four-component condensation of carbonyl compounds (aromatic aldehydes, heterocyclic ketones), malononitrile, β-keto esters, and hydrazine hydrate in ethanol in the presence of triethylamine as a catalyst, which occurs selectively, is developed. One-pot two-step modification of this method is proposed for the synthesis of spiro[(3 H)-indole-3,4 ′-(4′H)-pyrano[2,3-c]pyrazol]-2-ones.     

Synthesis of spiro[furan-3,3′-indolin]-2′-ones by PET-catalyzed [3+2] reactions of spiro[indoline-3,2′-oxiran]-2-ones with electron-rich olefins

An efficient procedure for the synthesis of spiro[furan-3,3′-indolin]-2-ones and dispiro[cycloalkane-1,2′-furan-3′,3″-indolin]-2″-ones has been achieved in high yields and stereoselectivity by photoinduced electron transfer-catalyzed [3+2] reactions of substituted spiro[indoline-3,2′-oxiran]-2-ones with olefins. The reactions proceed by ring opening of spiro[indoline-3,2′-oxiran]-2-ones via C_β–O bond cleavage and subsequent cycloaddition with olefins by using 2,4,6-triphenylpyrylium tetarfluoroborate (TPT) as a sensitizer.     

Copper(I) hexafluorosilicateπ-complexes with allylammonium salts. Synthesis and crystal structure of [CuOOCH·C3H5NH3]2SiF6 and [Cu2Cl3·2C3H5NH3]2SiF6

Two novel copper (I) -complexes containing the SiF ₆ ^2– anion have been synthesized and studied by X-ray structure analysis. The crystals of the first title compound (A) are monoclinic, space group P2₁/b with a=13.039(5), b=10.586(4), c=6.072(2) Å, =100.23(2)°, and Z=2. The crystals of the second title compound (B) are triclinic, space group with a=14.495(5), b=7.633(2), c=6.429(8) Å, =90.67(8), =81.80(8), =94.05(3)°, and Z=1. In structure A, the copper cations and the bridge formiate anions form infinite [Cu(HCOO)]_n spirals, which are cross-linked due to the -interaction between copper and the double bond AA and the strong hydrogen bonds N–H... F(SiF ₆ ^2– ) to form a three-dimensional framework. In structure B, allylammonium similarly acts as a bridge linking the SiF ₆ ^2– and Cu₄Cl ₆ ^2– anions into layers.Lvov State University. Institute of Physical Chemistry, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 4, pp. 141–148, July–August, 1993.Translated by T. Yudanova     

Chromeno[3″,4″:5′,6′]pyrido[2′,3′:4,5]thieno[3,2-e]pyridine—A New Heterocyclic System. Synthesis and Molecular and Crystal Structures

Russian Journal of Organic Chemistry - Multicomponent condensation of cyanothioacetamide, 4-fluoro-2-methylbenzaldehyde, methyl 4-methyl-3-oxopentanoate, and 3-(2-bromoacetyl)-2H-chromen-2-one...     

N-acetylchloroacetamide in the synthesis of functionally-substituted pyrido[3′,2′∶4,5]-thieno[3,2-d]pyrimidin-4(3H)-ones

3-Cyano-2(1H)-pyridinethiones react with N-acetylchloroacetamide in ethanol in the presence of KOH to give pyrido[3,24,5]thieno[3,2-d]pyrimidin-4(3H)-ones.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 837–840, June, 1997.