Heterocycles of biological importance. Part 2. Novel synthesis and pharmacological evaluation of 5-amino-3-alkyl-1-(2-pyridyl)pyrazoles and 5-amino-3-phenyl-1-(2-pyridyl)pyrazole from allenic or acetylenic nitriles and 2-hydrazinopyridine

2-Hydrazinopyridine reacts with allenic and acetylenic nitriles to give 5-amino-3-alkyl-1-(2-pyridyl)pyrazoles 6 in excellent yields. One of these compounds, 6e has been shown to possess anticonvulsant and anti-electroshock properties. Phenyl propynenitrile also reacts with hydrazinopyridine to give 5-amino-3-phenyl-1-(2-pyridyl)pyrazole ( 11 ) in quantitative yield.     

3-Pyridylisoxazoles as prototypes of antiaggregatory agents

A series of 5-alkyl-3-pyridylisoxazoles was synthesized using the 3-(3-pyridyl)isoxazole scaff old. All compounds of the series possessed antiaggregatory activity in the concentration range of 6?10^–6–6?10^–4 mol L^–1. Analysis of the experimental data on the antiaggregatory activity revealed the presence of spatial constraints for the alkyl substituents in position 5 of the isoxazole ring. 5-Alkyl-3-(3-pyridyl)isoxazoles are rather selective for platelet membrane receptors.     

3-Alkyl-2-[3(4)-pyridyl]-5-(2-vinyloxyethoxymethyl)-oxazolidines

1-Alkylamino-3-(2-vinyloxyethoxy)-2-propanols react with 3-and 4-pyridinecarbaldehydes to give equimolar mixtures of cis- and trans-3-alkyl-5-(2-vinyloxyethoxymethyl)-2-[3(4)-pyridyl]oxazolidines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 104–108.Original Russian Text Copyright © 2005 by Kukharev, Stankevich, Lobanova, Klimenko, Kukhareva.     

Regioselective synthesis of 1-alkyl-5-(indol-3-yl- and -2-yl)pyrrolidin-2-ones from available reagents

The reaction under mild conditions of 1-alkyl-5-hydroxypyrrolidin-2-ones with different indoles having a free 3 position leads exclusively to 1-alkyl-5-(indol-3-yl)pyrrolidin-2-ones but if position 3 is occupied to 1-alkyl-5-(indol-2-yl)pyrrolidin-2-ones.     

Pyridine-substituted hydroxythiophenes. V. Preparation of 5-(2-, 3-and 4-pyridyl)-2-hydroxythiophenes

5-(2-, 3- and 4-Pyridyl)-2-t-butoxythiophenes have been prepared in very good yields by Pd(0) catalyzed cross-coupling of the three isomeric bromopyridines with 5-trimethylstannyl-2-t-butoxythiophene derived from 2-bromothiophene via 2-t-butoxythiophene. Dealkylation of 5-(2-, 3- and 4-pyridyl)-2-t-but-oxythiophenes with boron trifluoride etherate in dichloromethane at room temperature led to predominant formation of rearranged products, 5-(2- and 3-pyridyl)-3-t-butyl-3-thiolene-2-ones, together with a small amount of 5-(2- and 3-pyridyl)-2-hydroxythiophenes as a mixture of two tautomeric keto forms in the case of the 2-pyridyl and the 3-pyridyl isomers, and exclusive formation of rearranged product in the case of the 4-pyridyl isomer. However, dealkylation of 2-methoxy-5-(2-, 3- and 4-pyridyl)thiophenes, prepared similarly to the 5-(2-, 3- and 4-pyridyl)-2-t-butoxythiophenes, with boron tribromide under the same reaction conditions as above resulted exclusively in the tautomeric mixture of 5-(2- and 3-pyridyl)-3-thiolene-2-ones and 5-(2- and 3-pyridyl)-4-thiolene-2-ones in the case of the 2-pyridyl and 3-pyridyl isomers. In the case of the 4-pyridyl isomer polymerization took place.     

2-Oxooxazolopyridines. 2. Synthesis of N′-alkyl-N-(2-oxo-3-pyridyl)ureas

In reactions with amines 2-oxo-7-trifluoromethyl-5-phenyl-(1H)-oxazolo[5,4-b]pyridines and alkyl N-(2-oxo-3-pyridyl)carbamates are converted into N-alkyl- and N,N-dialkyl-N-(2-oxo-3-pyridyl)ureas respectively.For Communication 1, see [1].Riga Technical University, Riga LV-1048, Latvia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 385–391, March, 1998.     

Efficient Heck reactions catalyzed by a highly recyclable palladium(II) complex of a pyridyl-functionalized imidazolium-based ionic liquid

The reactions of 2-(2-pyridyl)imidazole with alkyl iodides at 25 degrees C in the presence of base gave rise to 1-alkyl-2-(2-pyridyl)imidazole. Subsequent neat reactions with alkyl or polyfluoroalkyl halides at 100 degrees C, followed by anion exchange with LiN(SO(2)CF(3))(2), generated the mono-quaternary ionic liquids. All of them have excellent thermal stability and wide liquid range. Most of the salts with asymmetric N-substituents are liquid at room temperature. The effect of N-substituent variation and symmetry on NMR, TGA and DSC is discussed. Reaction of with palladium(II) chloride produced a mononuclear palladium ionic liquid complex, the structure of which was confirmed by single-crystal X-ray diffraction analysis. The Heck cross-coupling reactions using in ionic liquid demonstrated excellent stability and recyclability.     

Reaction of 4-acylaminomethylpyridine N-oxides with 5-monosubstituted barbituric acids in presence of acetic anhydride

The 5-alkyl-5-[(3,5-dimethylbenzoylamino)(4-pyridyl)methyl]barbituric acids are obtained in the title reactions, but they fail when barbituric or 5-phenylbarbituric acids are used. These results are explained by the pK_a values of barbituric acids.     

The preparation of 5-(2-bromoethyl)-2-iminooxazolidines via the von braun cyanogen bromide reaction

The reaction of certain 1-alkyl-3-pyrrolidinols with cyanogen bromide in ether solution produced 3-alkyl-5-(2-bromoethyl)-2-iminooxazolidines. 5-(2-Bromoethyl)-2-ethyl-2-imino-5-phenyloxazolidine was tested for and found devoid of anorectic activity.     

Chemistry of 6 -pyrido[4,3- ]carbazoles part II: synthetic approaches to 6 -9-methoxy-5, 11-dimethylpyrido[4,3- ] fluorenes

Synthetic approaches to 6 -9-methoxy-5, 11-dimethylpyrido[4,3- ] fluorene are described, thus 2-[1-(4-pyridyl)ethyl]6-methoxyindanone has been reacted with vinylmagnesium bromide to yield 2-[1-(4-pyridyl)ethyl]-6 methoxy-1-vinyl-1-indanol. However, on dehydration this compound rearranges to 2-[1-(4-pyridyl)ethyl]-3-ethylidene-5-methoxyindene rather than the required isomer 3-ethylidine-2-[1-(4-pyridyl)ethyl]-5-methoxyindane needed fro pericyclic ring-closure to the pyrido[4,3- ]fluorene system. Reaction of -2-[1-methyl-1-(4-pyridyl)methylene]-6-methoxyindanone with ethylene triphenylphosphorane similarly gives 6-methoxy-spiro-2-[1-(2,3-dimethyl-3-(4-pyridyl)-cyclopropyl) indanone rather than the desired indane.     

Application of N-(ω-bromoalkyl)tetrazoles for the preparation of bitopic ligands containing pyridylazole chelators or azole rings as building blocks for iron(II) spin crossover polymeric materials

1-(3-Bromopropyl)tetrazole, 2-(3-bromopropyl)tetrazole, 1-(4-bromobutyl)tetrazole, and 2-(4-bromobutyl)tetrazole were synthesized with the aim to prepare flexible bitopic ligands contaning 1- or 2-substituted tetrazole ring linked through 1,3-propylene or 1,4-butylene spacer with pyridylazole or azole unit. Twenty-six novel ligands i.e., α-(pyridylazolyl)-ω-(tetrazolyl)alkanes, α-(tetrazolyl)-ω-(1,2,3-triazolyl)alkanes, and α-(tetrazol-1-yl)-ω-(tetrazol-2-yl)alkanes were prepared by an alkylation of sodium salts of 5-(2-pyridyl)tetrazole, 3-(2-pyridyl)-1,2,4-triazole, 3-(2-pyridyl)pyrazole, 1,2,3-triazole, and 1,2,3,4-tetrazole with N-(ω-bromoalkyl)tetrazoles. An alkylation of 5-(2-pyridyl)tetrazole, 1,2,3,4-tetrazole, and 1,2,3-triazole afforded both N1- and N2-regioisomer whereas in the case of 3-(2-pyridyl)-1,2,4-triazole and 3-(2-pyridyl)pyrazole only N1 isomers were isolated. The positions of alkylation were confirmed by X-ray diffraction studies of 1-(5-(2-pyridyl)tetrazol-2-yl)-4-(tetrazol-1-yl)butane, 1-(3-(2-pyridyl)-1,2,4-triazol-1-yl)-4-(tetrazol-2-yl)butane, 1-(3-(2-pyridyl)pyrazol-1-yl)-4-(tetrazol-1-yl)butane, and 1-(tetrazol-1-yl)-4-(1,2,3-triazol-1-yl)butane. Preliminary investigations of magnetic properties of iron(II) complex with 1-(3-(2-pyridyl)-1,2,4-triazol-1-yl)-4-(tetrazol-1-yl)butane revealed that obtained product exhibit thermally induced spin transition accompanied by the thermochromic effect.     

Reactions of 2-chloro-2-(4-pyridyl)propane with nucleophiles. Substitution on tertiary carbon

The reaction of 2-chloro-2-(4-pyridyl)propane ( 2 ) with lithium 2-propanenitronate affords the C-alkylation product 2-nitro-3-(4-pyridyl)-2,3-dimethylbutane ( 3 ), the Michael-adduct 2-nitro-2-methyl-4-(4-pyridyl)pentane ( 4 ), 4-isopropenylpyridine ( 5 ) and 2-(4-pyridyl)-2-propanol ( 6 ). Of these four products, only the formation of 3 is suppressed when the reaction is performed in the presence of radical inhibitors. The reaction of compound 2 with sodium azide gives the tertiary substitution product 2-azido-2-(4-pyridyl)propane ( 8 ). The reaction is not influenced by radical inhibitors. This is also the case in the reaction of 2 with sodium benzenethiolate, which affords 2-mercaptophenyl-2-(4-pyridyl)propane ( 9 ) and 1-mercaptophenyl-2-(4-pyridyl)propane ( 10 ). Compound 5 , the product of an E₂-type elimination is also formed in the azide and thiolate reactions. A Michael type addition of sodium benzenethiolate to 5 explains the formation of 10 . Similarly, generation of 5 in reactions of 2 with sodium methanethiolate and sodium cyanide accounts for the formation of 1-mercaptomethyl-2-(4-pyridyl)propane ( 11 ) and 3-(4-pridyl)butanenitrile ( 12 ), respectively.     

Furan ring opening–indole ring closure: SnCl2-induced reductive transformation of difuryl(2-nitroaryl)methanes into 2-(2-acylvinyl)indoles

A simple and efficient method for the synthesis of 2-(2-acylvinyl)-3-(5-alkyl-2-furyl)indoles by reductive recyclization of bis(5-alkyl-2-furyl)(2-nitroaryl)methanes is reported. This transformation was carried out by heating the substrates with SnCl₂·2H₂O in ethanol. The intermediate nitrosoarene moiety interacted with the furan ring via electrophilic nitrogen attack onto the C(2) position of the furan ring. It was shown that the related bis(5-alkyl-2-thienyl)(2-nitroaryl)methanes under the same reaction conditions failed to undergo the analogous recyclization and were transformed into bis(5-alkyl-2-thienyl)(2-aminoaryl)methanes.     

Highly effective stereoselective synthesis of vinyl ethers of 5-alkyl-2-(2-furyl)-5-hydroxymethyl-1,3-dioxanes

The vinylation of cis-5-alkyl-5-hydroxymethyl-2-(2-furyl)-1,3-dioxanes in the KOH–DMSO system in acetylene at atmospheric or elevated pressures (85-100°C, 3 h) takes place stereoselectively and leads to the formation of cis-5-alkyl-2-(2-furyl)-5-vinyloxymethyl-1,3-dioxanes with yields of up to 93%.     

Preparation and analytical properties of chelating resins containing heterocyclic formazane derivatives

Chromatographia - By introducing pyridine and thiazole rings into polyacrolein, poly[1-(2-pyridyl)-3-(vinyl)-5-(phenyl)-formazane] (PPF), poly[1-(2-pyridyl)-3-(vinyl)-5-(2-arsonophenyl)-formazane]...     

Heterocyclic compounds from 3,3-dimercapto-1-aryl-2-propen-1-ones. Note 3. Condensation with N-methyl-o-phenylenediamine and N-benzyl-o-phenylenediamine

Two seven-membered ring compounds and three five-membered ring compounds were obtained by reaction in hot xylene of 3,3-dimercapto-l-phenyl-2-propen-1-one (1) with N-alkyl-o-phenylenediamines (2) . Compounds isolated were the 4-phenyl-5-alkyl-1,5-dihydro-2H-1,5-benzodiazepine-2-thiones (3) the 1-alkyl-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-thiones (4) , the 1-alkyl-2-phenacylbenzimidazoles (5) , the 1-alkyl-2-phenylbenzimidazoles (6) and the 1-alkyl-2-methylbenzimidazoles (7) . The structures of these compounds were elucidated from their chemical reactivity and their nmr and ir spectra.     

Synthesis of 2-(4-cyanophenyl)-5-(4-n-alkyl- and alkoxyphenyl) pyridines

New liquid-crystalline 2-(4-cyanophenyl)-5-(4-alkyl- and alkoxyphenyl)pyridines were obtained by condensation of 1-dimethylamino-3-dimethylimmonia-2-(4-alkyl- or alkoxyphenyl)-1-propene perchlorates with 4-cyanoacetophenone and subsequent conversion of the 1-dimethylamino-2-(p-alkyl- or alkoxyphenyl)-4-(p-cyanobenzoyl)-1,3-butadienes to 5-(4-alkyl- or alkoxyphenyl)-2-(4-cyanophenyl)pyrylium perchlorates and refluxing of the latter with ammonium acetate in acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1392–1394, October, 1985.     

Recyclization of ethyl 1-alkyl-5-benzoyl-6-methylsulfanyl-2-oxo-1,2-dihydropyridine-3-carboxylates into Bicyclic <Emphasis Type="Italic">N</Emphasis>-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxamide derivatives by the action of nitrogen-containing 1,4- and 1,5-binucleophiles

Reactions of ethyl 1-alkyl-5-benzoyl-6-methylsulfanyl-2-oxo-1,2-dihydropyridine-3-carboxylates with nitrogen-containing 1,4- and 1,5-binucleophiles (o-phenylenediamine, o-aminobenzenethiol, ethane-1,2-diamine, and propane-1,3-diamine) involved recyclization, leading to the formation of fused N-alkyl-5-benzoyl- 2-oxo-1,2-dihydropyridine-3-carboxamides, diethyl 6,6′-oxybis(1-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxylates), and diethyl 6,6′-[ethane-1,2-diyl(or propane-1,3-diyl)diimino]bis(1-alkyl-5-benzoyl-2-oxo-1,2-dihydropyridine-3-carboxylates), depending on the reactant ratio. The sequence of formation of intermediate recyclization products was determined.     

Base- and acid-catalyzed condensation reactions of reissert compounds with vinylpyridines

The hydrochloric acid-catalyzed condensation of 2-p-anisoyl-1,2-dihydroisoquinaldonitrile ( 3 ) with 2-vinylpyridine gave 2-(1-isoquinolyl)-3-(2-pyridyl)-5-p-anisylpyrrole ( 4 ), and the corresponding reaction of 3 with 4-vinylpyridine afforded 2-(1-isoquinolyl)-3-(4-pyridyl)-5-p-anisylpyrrole (5). The condensation of the lithium salt of 3 with 4-vinylpyridine gave α-(4-pyridyl)-β-(1-iso-quinolyl)-p-methoxypropiophenone ( 10 ), which was cyclized to 2-(4-pyridyl)-3-p-anisylpyrrolo-[2,1-a]isoquinoline (7) by the action of concentrated hydrochloric acid. 2-(4-Pyridyl)-3-phenyl-pyrrolo[2,1-a]isoquinoline ( 6 ) and 2-(2-pyridyl)-3-p-anisylpyrrolo[2,1-a]isoquinoline ( 8 ) were prepared by analogous sequences of reactions.     

含吡啶基取代多苯基芳基有机硅化合物的合成

2,4,5-三苯基、3-吡啶基环戊二烯酮(4),分别与烯丙基三乙氧基硅烷及乙烯基三乙氧基硅烷发生Diels-Alder反应,生成2,4,5-三苯基3-吡啶基苄基三乙氧基硅烷(5)、2,4,5-三苯基3-吡啶基苯基三乙氧基硅烷(6)、1,3,4-三苯基2-吡啶基苯(7)和1,3,4-三苯基2-吡啶基二环[2.2.1]-2-烯-7-酮(8)。它们的产率分别为75％、41％、10％和10％。