Intramolecular charge transfer processes in a series of styryl derivatives of pyridine and quinoline N-oxides

Intramolecular charge transfer processes in a series of thetrans-isomers of styryl derivatives of pyridines and quinolines, their hydrochlorides and molecular complexes with BF₃ have been studied by electronic and IR spectroscopy. Electron donor groups involved in direct resonance conjugation with the N-oxide group intensify these processes, while electron acceptor nitro groups somewhat weaken them. Protons and BF₃ coordinate to the oxygen of the NO group to form strong 11 complexes, except in the cases of 4-(4-dimethylaminostyryl)quinoline and pyridine N-oxides, in which a second acceptor molecule adds to the amino group.Petrozavodsk State University, Petrozavodsk 185640, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1093–1102, August, 1998.     

Chlorination of quinoline

Chlorination of Quinoline at 160–190° without solvent gave a mixture of compounds. The five major components were isolated and identified as 3,4-dichloro-, 3,4,6-, 3,4,8-trichloro-, 3,4,6,8-tetrachloro- and 3,4,6,7,8-pentachloroquinolines.     

New aminoalkyl and vinyl derivatives of pyridine and quinoline

New bases have been obtained by the Mannich reaction from 2-methyl-5-vinylpyridine and from 2,4-dimethylquinoline. Decomposition of quaternary salts of these bases has yielded previously unknown vinyl derivatives of pyridine and quinoline.     

Magnesium hydrides and the dearomatisation of pyridine and quinoline derivatives

Reactions of the β-diketiminato n-butyl magnesium complex, [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)Mg(n)Bu], with a range of substituted pyridines and fused-ring quinolines in the presence of PhSiH(3) has been found to result in dearomatisation of the N-heterocyclic compounds. This reaction is proposed to occur through the formation of an unobserved N-heterocycle-coordinated magnesium hydride and subsequent hydride transfer via the C2-position of the heterocycle prior to hydride transfer to the C4-position and formation of thermodynamically-favoured magnesium 1,4-dihydropyridides. This reaction is kinetically suppressed for 2,6-dimethylpyridine while the kinetic product, the 1,2-dihydropyridide derivative, was isolated through reaction with 4-methylpyridine (4-methylpyridine), in which case the formation of the 1,4-dihyropyridide is prevented by the presence of the 4-methyl substituent. X-ray structures of the products of these reactions with 4-methylpyridine, 3,5-dimethylpyridine and iso-quinoline comprise a pseudo-tetrahedral magnesium centre while the regiochemistry of the particular dearomatisation reaction is determined by the substitution pattern of the N-heterocycle under observation. The compounds are all air-sensitive and exposure of the magnesium derivatives of dearomatised pyridine and 4-dimethylaminopyridine (DMAP) to air resulted in ligand rearomatisation and the formation of dimeric μ(2)-η(2)-η(2)-peroxomagnesium compounds which have also been subject to analysis by single crystal X-ray diffraction analysis. An unsuccessful extension of this chemistry to N-heterocycle hydrosilylation is suggested to be a consequence of the low basicity of the silane reagent in comparison to the pyridine substrates which effectively impedes any further interaction with the magnesium centres.     

Synthesis in a series of quinoline derivatives

Monomeric substances, 8-methacryloxyquinolines were synthesized with the object of obtaining preparations with prolonged action.For part V, see [1].     

Synthesis of a new series of pyridine and fused pyridine derivatives

The reaction of 4-methyl-2-phenyl-1,2-dihydro-6-oxo-5-pyridine- carbonitrile (1) with arylidene malononitrile afforded isoquinoline derivatives 2a,b. 6-Chloro-4-methyl-2-phenyl-5-pyridinecarbonitile (3) obtained by chlorination of compound 1 with phosphoryl chloride was converted into 6-amino-4-methyl-2-phenyl-5-pyridinecarbonitrile (4) and 6-hydrazido-4-methyl-2-phenyl-5-pyridinecarbonitrile (5) in good yield, through reactions with ammonium acetate and hydrazine hydrate, respectively. Treatment of 4 with ethyl acetoacetate, acetic anhydride, formic acid, urea and thiourea gave the corresponding pyrido [2,3-d] pyrimidine derivatives 7-10a,b. A new series of 6-substituted-4-methyl-2-phenyl-5-pyridine carbonitriles 11-13 has been synthesized via reaction of 4 with phenyl isothiocyanate, benzenesulphonyl chloride and acetic anhydride. Treatment of 4 with malononitrile gave 1,8-naphthyridine derivative 14. The reactivity of hydrazide 5 towards acetic acid, phenylisothiocyanate and methylacrylate to give pyrazolo-[3,4-b]-pyridine derivatives 15-17 was studied. Treatment of 5 with acetic anhydride, phthalic anhydride and carbon disulphide gave pyridine derivatives 18,19 and 1,2,4-triazolo-[3,4-a]-pyridine derivative 20.     

RP-HPLC determination of lipophilicity in series of quinoline derivatives

In the present paper we describe results on the synthesis and lipophilicity determination of a series of biologically active compounds based on their heterocyclic structure. For synthesis of styrylquinoline-based compounds we applied microwave irradiation and solid phase techniques. The correlation between RP-HPLC retention parameter log k (the logarithm of retention factor k) and log P data calculated in various ways is discussed, as well as, the relationships between the lipophilicity and the chemical structure of the studied compounds.      

Synthesis of pyridine and quinoline derivatives of ferrocene from β-chloro-β-ferrocenylacrolein

2-Ferrocenylquinolines that contain a hydroxy or methoxy group in the 7 position were obtained by the reaction of -chloro--ferrocenylacrolein with m-anisidine and with m-aminophenol. The introduction of aniline in this reaction leads to the formation of -ferrocenyl--phenylaminoacrolein anil hydrochloride, which cannot be converted to 2-ferrocenylquinoline. 2,3,6-Trisubstituted pyridines that contain a ferrocenyl substituent in the 6 position were obtained by condensation of -chloro--ferrocenylacrolein with -dicarbonyl compounds.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1376–1378, October, 1981.     

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.     

Liquid-crystalline quinoline derivatives

A number of novel liquid crystals have been synthesized. 2-Phenylquinolines with alkyl or alkoxyl substituents in positions 6 and 4' show a texture typical of nematic mesophases and are characterized by a greater thermal stability than Schiff bases bearing the same substituents. The possibility of lowering the melting temperatures by means of eutectic mixtures is discussed.     

Investigation of quinoline derivatives

The dehydrogenation of mononitro-1,2,3,4-tetrahydroquinolines and several of their N-acyl derivatives to the corresponding aminoquinolines was accomplished with various dehydrogenating agents. The maximum yields of aminoquino lines (15–20%) can be obtained when palladium on carbon is used as the dehydrogenating agent.See [1] for communication I.DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 103—104, January, 1972     

Syntheses of quinoline derivatives

In order to study the relationship between structure and biological activity we have synthesized 5-alkoxymethyl- and 5-aryloxymethyl-7-bromo-8-quinolinols.For part II, see [1].     

Investigation of quinoline derivatives

Some dinitro derivatives of 1,2,3,4-tetrahydroquinoline and its N-acyl analogs were synthesized. The structures of the dinitro isomers obtained were confirmed by NMR, UV, and IR spectroscopic data.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–83, January, 1973.     

Isocyanates of the quinoline series

The isocyanates obtained by rearrangement of azides of quinaldic and quinoline-2,4-di-carboxylic acids exist as trimers. A number of urethanes were obtained by the decomposition of these azides ta the presence of alcohols. The possibility of the use of the azide of quinoline-2,4-carboxylic acid to obtain polymers was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 527–528, April, 1972.     

Comparative mass spectrometric behavior of o-hydroxynitroso derivatives of the quinoline,isoquinoline, and coumarin series

Benzo-substituted ortho-hydroxynitrosoquinoline and isoquinoline are found in the gas phase predominantly as the hydroxyimino-ortho-quinoid tautomeric form and under electron bombardment they do not undergo a second order Beckmann rearrangement. Molecular ions of 4-hydroxy-3-nitrosocarbostyryls and coumarin have almost exclusively the structure of the corresponding 2,4-dioxo-3-hydroxyiminohetarene; they also do not undergo rearrangement and decompose predominantly by retrodiene cleavage.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1243–1247, September, 1989.     

Styryl derivatives of quinoline N-oxide

A new method has been developed for the synthesis of hitherto unknown styryl derivatives of quinoline N-oxide. Electron spectroscopy has shown the occurrence of intramolecular charge transfer processes in these compounds.Petrozavodsk State University, Petrozavodsk 185640. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 518–521, April, 1995. Original article submitted March 14, 1995.