An unusual reaction of 2-(2-pyridylcarbonyl)- and 2-(2-quinolylcarbonyl)benzoyl chlorides with p-nitroaniline

In the reaction of 2-(2-pyridylcarbonyl)benzoyl chloride, which exists in the form of 6,11-dioxo-6,11dihydrobenzo[b]quinolizinium chloride, with p-nitroaniline, 2-(4-nitrophenylimino)-6, 11-dihydro-2H-benzo-[b]quinolizine-6, I I -dione is unexpectedly formed. When it reacts with water or methanol there is an opening of the quinolizine ring and aromatization of the quinoid fragment with the formation of 2-[4-(4nitrophenylamino)-2-pyridylcarbonyl]benzoic acid or its methyl ester. Under the action of antimony pentachloride, 2- 2-quinolylcarbonyl)benzoylchloride-3 (2-quinolyl)-3-chloro- 1, 3-dihydrobenzo[c]furan-1 -one -is converted to 3-(2-quinolyl)-1,3-dihydrobenzo[c]furan-1-on-3-ylium hexachlorantimonate, which undergoes isomerizing recyclization upon heating to 7,12-dioxo-7,12-dihydrobenzo[b/ hexachloroantimonate. The latter enters into an analogous reaction with p-nitroaniline, thereby forming 5-(4-nitrophenylimino)-7,12-dihydro-5H-dibenzo[b,f]quinolizine-7,2-dione.Riga Technical University, Riga LV-1048. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 938–944, July, 1995. Original article submitted May 31, 1995.     

Synthesis of 2,3-dihydroselenazolo[3,2-a]pyridinium salts based on reactions of pyridine-2-selanyl chloride with alkenes and dienes

The reaction of pyridine-2-selanyl chloride with alkenes and dienes gives 2,3-dihydro[1,3]selenazolo- [3,2-a]pyridinium derivatives as addition-cyclization products involving closure of the ring at the pyridine nitrogen atom of the selanylating electrophile.     

Synthesis of 4H-3,1-benzoxazin-4-ones and 4-(3H)quinazolinones from anthranilic acids and their derivatives by the use of triphenyl phosphite and pyridine

A series of 2-substituted 4H-3,1-benzoxazinones and 2,3-disubstituted 4-(3H)quinazolinones have been synthesized in mild conditions by the use of triphenyl phosphite and pyridine as cyclising medium. Benzox-azinones are produced either by ring closure of 2-(acylamino)benzoic acids or in the reaction of benzoic acid with anthranilic acids. In the presence of aniline, the reaction leads to quinazolinones.     

Superelectrophilic Activation of 8-Hydroxyquinoline in Acid Media and Its Reactions with Weak Nucleophiles

According to the ¹H and ^{1 3}C NMR data, 5-azonia-4-hydroxynaphthalen-1-onium cation, generated by protonation of 8-hydroxyquinoline in the system CF₃SO₃H-SbF₅, reacts with cyclohexane to give diprotonated 5,6,7,8-tetrahydroquinolin-8-one. Further reaction of the latter with cyclohexane yields 5,6,7,8-tetrahydroquinolinium ion. The reaction of 8-hydroxyquinoline with benzene in the presence of aluminum bromide or chloride gives 6-phenyl-5,6,7,8-tetrahydroquinolin-8-one and product of its intramolecular cyclization, 11-hydroxy-6,11-dihydro-6,11-methano-5H-benzo[5,6]cyclohepta[1,2-b]pyridine. The effect of the protonated nitrogen atom on the electrophilicity of dications is discussed.     

Action of benzyl chloride on 2-(N,N-dimethylamino)pyridine and 2-benzoylaminopyridine

The results of the reaction of 2-(N,N-dimethylamino)pyridine ( 1 ) and 2-benzoylaminopyridine ( 2 ) with benzyl chloride ( 3 ) proved that 3 did not undergo direct reaction with the pyridine ring to form a C-benzyl product.     

Derivatives of octahydropyrrolo[4,3,2-m,n]-acridine. 5. Alkylation of 1-methyl and 1-aryl-4,4,8,8-tetramethyl-2,3,4,5,7,8,9,10-octahydropyrrolo[4,3,2-m,n]acridin-10-ones

4,4,8,8-Tetramethyl-2,3,4,5,7,8,9,10-octahydropyrrolo[4,3,2-m,n]acridin-10-ones were alkylated at the nitrogen atom of the pyrrole ring by successive treatment with sodium hydride and an alkyl halide. Treatment of the neutral molecule with methyl iodide gave alkylation at the nitrogen atom of the pyridine ring. Derivatives of pyrrolo[4,3,2-m,n]acridine with no substituent at position 2 readily lost a proton from the NH group of the pyrrole ring to give bipolar structures.For Communication 2, see [1]; for Communications 3 and 4, see [2, 3].Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 794–802, June, 1998.     

Hydration and interfacial activity of methyl 8-pyridyloctanoates and extraction of copper(II) from chloride solutions

The interfacial tension of individual methyl 8-pyridyloctanoates containing the hydrophobic group at different positions of the pyridine ring was measured at the tolune/water interface. The extraction of copper(II) fom chloride solutions with these reagents was studied. Considering solvent extraction, methyl 8-(2-pyridyl)octanoate had a worse orientation at the interface than methyl 8-(3-pyridyl)octanoate and methyl 8-(4-pyridyl)octanoate. PM3 semiempirical quantum chemical computing indicates that the oxygen of the carbonyl group forms hydrogen bonds with water molecules more easily than the second oxygen atom and the nitrogen in the pyridine ring. However, at the adsorption layer, this hydration is possible only for methyl 8-(2-pyridyl)octanoate. Methyl 8-(3-pyridyl)octanoate and methyl 8-(4-pyridyl)octanoate are strong copper extractants from chloride solutions, while extraction is not observed for methyl 8-(2-pyridyl)octanoate.     

Cyclization of ethyl endo-5-norbornene-2-carboxylate with hetarene sulfenyl chlorides

Cyclization of ethyl endo-5-norbornene-2-carboxylate with 1,3-benzothiazole-2-sulfenyl and 3-methoxycarbonylpyridine-2-sulfenyl chlorides follows two directions, namely, electophilic lactonization of unsaturated ester or polar cycloaddition of sulfenylating reagent to the multiple bond accompanied by ring closure by the nitrogen atom of the thiohetaryl fragment.     

Synthesis of substituted 1-(2-arylvinyl)-2-azolyl-1-pyridylethanols-1

A series of new 1-(2-arylvinyl)-2-azolyl-1-pyridylethanols-1 has been obtained with various positions of the nitrogen atom in the pyridine fragment and with substituents in the benzene ring, by the reaction of (2-arylvinyloxiran-2-yl)pyridines with triazole and imidazole, for agrochemical screening. The compounds mentioned displayed high fungicidal activity. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1167–1174, August, 2007.     

2-Acyl(aroyl)-1,1,3,3-tetracyanopropenides: III. Heterocyclization by the action of hydrogen halides

2-Acyl(aroyl)-1,1,3,3-tetracyanopropenides reacted with hydrogen halides along two concurrent pathways with formation of furan or pyridine derivatives. The reaction in butan-2-ol afforded 2-amino-4-acyl-(aroyl)-6-halopyridine-3,5-dicarbonitriles, whereas the major products in the reactions with HCl and HBr in aqueous solution were the corresponding 2-(5-amino-2-aryl-2-chloro(bromo)-4-cyano-2,3-dihydrofuran-3-ylidene)malononitriles. The reaction with aqueous hydrogen iodide was accompanied by reductive deiodination and produced 2-(5-amino-2-aryl-4-cyano-2,3-dihydrofuran-3-ylidene)malononitriles.     

Special features of the interaction of pyridine and quinoline derivatives, and related compounds with triphenylphosphine

Using pyridine, quinoline, and related compounds as examples, it has been shown that their interaction with triphenylphosphine occurs via different pathways. Reaction of triphenylphosphine with N-vinylisonicotinic acid chloride leads to the mixture of 1,2-bis(triphenylphosphoniumchlorido)ethane and 4-carboxy-2-(triphenylphosphoniumchloridoethyl)pyridine. In the case of α-(N-2-carboxyquinolinylbromido)-β-bromopropionic acid, the reaction with triphenylphosphine proceeds via phosphine attack on the oxygen atom with elimination of quinaldinic acid, and subsequent nucleophilic substitution with the formation of 3-(triphenylphosphoniumbromido) propionic acid bromide.     

Ru(3)(CO)(12)-catalyzed coupling reaction of sp(3) C-H bonds adjacent to a nitrogen atom in alkylamines with alkenes.

Catalytic reactions which involve the cleavage of an sp(3) C-H bond adjacent to a nitrogen atom in N-2-pyridynyl alkylamines are described. The use of Ru(3)(CO)(12) as the catalyst results in the addition of the sp(3) C-H bond across the alkene bond to give the coupling products. A variety of alkenes, including terminal, internal, and cyclic alkenes, can be used for the coupling reaction. The presence of directing groups, such as pyridine, pyrimidine, and an oxazoline ring, on the nitrogen of the amine is critical for a successful reaction. This result indicates the importance of the coordination of the nitrogen atom to the ruthenium catalyst. In addition, the nature of the substituents on the pyridine ring has a significant effect on the efficiency of the reaction. Thus, the substitution of an electron-withdrawing group on the pyridine ring as well as a substitution adjacent to the sp(2) nitrogen in the pyridine ring dramatically retards the reaction. Cyclic amines are more reactive than acyclic ones. The choice of solvent is also very important. Of the solvents examined, 2-propanol is the solvent of choice.     

Detailed Studies of the Alkylation Sides of Pyridin‐2‐yl and 4,6‐Dimethylpyrimidin‐2‐yl‐cyanamides

Pyridin‐2‐yl‐ and 4,6‐dimethylpyrimidin‐2‐yl‐cyanamides entered into an alkylation reaction in the form of sodium salts. Pyridin‐2‐yl cyanamide 2 was alkylated at endo‐nitrogen atom of pyridine ring, while 4,6‐dimethylpyrimidin‐2‐yl cyanamide 1 was effectively alkylated at exo‐nitrogen atom of amino cyanamide group. The alkylation of cyanamides 1 and 2 with phenacylbromide gave the corresponding acetophenone derivatives. As a result of their intramolecular cyclization reactions 3‐(4,6‐dimethylpyrimidin‐2‐yl)‐5‐phenyloxazol‐2(3H )‐imine in the case of cyanamide 1 and 2‐amino‐3‐benzoylimidazo[1,2‐a ]pyridine in the case of cyanamide 2 were formed. The alkylated derivatives of pyridin‐2‐ylcyanamide 2 possess visible blue fluorescence with the main peak at 421 – 427 nm.     

Effect of aza substitution on the formation of anhydro bases of quinolylindoles

The reaction of quaternary salts of 3-(2-quinoxalinyl) indoles with hydroxylamine was investigated. It was established that the presence of a second pyridine nitrogen atom in the ring increases the positive -electron charge on the nitrogen atom of the quinoxaline ring and, as a consequence of this, markedly increases the contribution of dealkylation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1365–1368, October, 1980.     

Quaternization centers of N-methyl derivatives of imidazo[4,5-b]pyridine

It is shown that quaternization of isomers of 1-methylimidazo[4,5-b]pyridine and 3-methyl-imidazo[4,5-b]pyridine proceeds at different reaction centers — at the nitrogen atom of the imidazole ring in the first case and at the nitrogen atom of the pyridine ring in the second case.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1686–1688, December, 1973.     

Chain mechanism in the photocleavage of phenacyl and pyridacyl esters in the presence of hydrogen donors

[reaction: see text] Excited phenacyl and 3-pyridacyl esters of benzoic acid react with an excess of aliphatic alcohols in a chain reaction process involving hydrogen transfer from the ketyl radical intermediates, leading to benzoic acid in addition to acetophenone and 3-acetylpyridine, respectively, as the byproducts. While the maximum quantum yields reached 4 in both cases, the 2- or 4-pyridacyl ester photoreduction proceeded with the efficiency below 100% under the same conditions. The investigation indicates that a radical coupling between ketyl radicals, both formed from the excited ester by hydrogen abstraction from an alcohol, is accompanied by the elimination of benzoic acid from the ester ketyl radical itself. A partitioning between two reactions was found to be remarkably sensitive to the chromophore nature, such as a position of the nitrogen atom in the pyridacyl moiety. The magnitude of a radical chain process is dependent on the efficiency of consecutive steps that produce free radicals capable of a subsequent ester reduction. The driving force of a possible electron transfer from the ketyl radicals to the ester has been excluded on the basis of cyclic voltametry measurements. The observed quantum yields of photoreduction were found to be diminished by formation of relatively long-lived light absorbing transients, coproducts obtained apparently by secondary photochemical reactions. Additionally, it is shown that basic additives such as pyridine can further increase the efficiency of the photoreduction by a factor of 4. A radical nature of the reduction mechanism was supported by finding a large kinetic chain length of an analogous reaction initiated by free radicals generated thermally yet again when phenacyl or 3-pyridacyl benzoate was used. Both phenacyl and pyridacyl chromophores are pronounced to be valuable as the photoremovable protecting groups when high quantum and chemical yields of carboxylic acid elimination are important, but higher concentrations of the hydrogen atom donors are not destructive for a reaction system or are experimentally impractical.     

4-Hydroxy-2-quinolones 123. Amidation of 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-quinoline-4-carboxylic acid

The reaction of 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]quinoline-4-carboxylic acid with thionyl chloride is accompanied by a transformation of the oxazoloquinolone ring to give 4-chloro-1-(2,3-dichloropropyl)-2-oxo-1,2-dihydroquinoline-3-carboxylic acid chloride. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1034–1042, July, 2007.     

Synthesis and Structure of a Novel Compound [Cu_2(EDTA)(Py)_2(H_2O)_2]·2H_2O

1 INTRODUCTION Multinuclear coordination compounds have attrac-ted much attention due to their distinctive optical, elec-tric and magnetic properties as well as enzyme ana-logue[1～4]. It is important for carboxylic acid to de-sign this compound[5～8]. EDTA is a useful titrant formetal determination because EDTA molecule is easyto coordinate with a metal atom (1:1). Other types ofEDTA-M compounds are seldom to know except Ln2-M3(EDTA)3(H2O)11?12H2O[5] and (UO2 )2EDTA[9]. …     

Aroxydihydropyrans

A method was developed for the preparation of 2-pyridylmethoxy-3,4-dihydropyrans on the basis of the thermal interaction of vinyl ethers of 2-, 3-, and 4-pyridylcarbinols and acrolein. The addition of hydrogen, chlorine, and ethanol to the double bond of the dihydropyran ring was studied. The activity of the pyridine nitrogen atom in quaternization and complexing reactions was demonstrated. It was established that both reaction centers participate in the reaction with hydrogen chloride. Nine new compounds were isolated and characterized, and their structures were proved by means of PMR, IR, and UV spectroscopy.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1166–1171, September, 1972.     

Iron(III) complexes of sterically hindered tetradentate monophenolate ligands as functional models for catechol 1,2-dioxygenases: the role of ligand stereoelectronic properties

The iron(III) complexes of the monophenolate ligands 2-(bis(pyrid-2-ylmethyl)aminomethyl)-4-nitrophenol [H(L1)], N,N-dimethyl-N'-(pyrid-2-ylmethyl)-N'-(2-hydroxy-4-nitrobenzyl)ethylenediamine [H(L2)], N,N-dimethyl-N'-(6-methyl-pyrid-2-ylmethyl)-N'-(2-hydroxy-4-nitrobenzyl)ethylenediamine [H(L3)], and N,N-dimethyl-N'-(1-methylimidazole-2-ylmethyl)-N'-(2-hydroxy-4-nitrobenzyl)ethylenediamine [H(L4)] have been obtained and studied as structural and functional models for the intradiol-cleaving catechol dioxygenase enzymes. The complexes [Fe(L1)Cl(2)].CH(3)CN (1), [Fe(L2)Cl(2)] (2), [Fe(L3)Cl(2)] (3), and [Fe(L4)Cl(2)] (4) have been characterized using absorption spectral and electrochemical methods. The single crystal X-ray crystal structures of 1 and 2 have been successfully determined. Both the complexes possess a rhombically distorted octahedral coordination geometry for the FeN(3)OCl(2) chromophore. In 2, the phenolate oxygen, the pyridine nitrogen, an amine nitrogen, and a chloride ion are located on the corners of a square plane with the nitrogen atom of a -NMe(2) group and the other chloride ion occupying the axial positions. In 1, also the equatorial plane is constituted by the phenolate oxygen, the pyridine nitrogen, an amine nitrogen atom, and a chloride ion; however, the axial positions are occupied by the second pyridine nitrogen and the second chloride ion. Interestingly, the Fe-O-C angle of 136.1 degrees observed for 2 is higher than that (128.5 degrees ) in 1; however, the Fe-O(phenolate) bond distances in both the complexes are the same (1.929 A). This illustrates the importance of the nearby sterically demanding coordinated -NMe(2) group and implies similar stereochemical constraints from the other ligated amino acid moieties in the 3,4-PCD enzymes, the enzyme activity of which is traced to the difference in the equatorial and axial Fe-O(tyrosinate) bonds (Fe-O-C, 133 degrees, 148 degrees ). The nature of heterocyclic rings of the ligands and the methyl substituents on them regulates the electronic spectral features, Fe(III)/Fe(II) redox potentials, and catechol cleavage activity of the complexes. Upon interacting the complexes with catecholate anions, two catecholate to iron(III) charge transfer bands appear, and the low energy band is similar to that of catechol dioxygenase-substrate complex. Complexes 1 and 3 fail to catalyze the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H(2)DBC). However, interestingly, the replacement of pyridine pendant in 1 by the -NMe(2) group to obtain 2 restores the dioxygenase activity, which is consistent with its higher Fe-O-C bond angle. Remarkably, the more basic N-methylimidazole ring in 4 facilitates the rate-determining product releasing phase of the catalytic reaction, leading to enhancement in reaction rate and efficient conversion (77.1%) of the substrate to intradiol cleavage products as well. All these observations provide support to the novel substrate activation mechanism proposed for the intradiol-cleavage pathway.