Conformational analysis of pyridiniummethanes and their derivatives,according to data on the cotton-mouton effect

For the first time, using the Cotton-Mouton effect, a conformational analysis has been made of pyridinium, quinolinium, and isoquinolinium salts in the dissociated form, these salts being structural analogs of diphenylmethane and benzophenone. It has been established that in the organic monocations with a geminal position of the aromatic and heteroaromatic rings, no major differences in spatial structure are observed in comparison with the uncharged analogs. In the bicationic systems, the aromatic rings are turned as much as 70–90°.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2761–2766, December, 1991.     

Sels de N-alcoxyquinoléinium et d'isoquinoléinium porteurs d'une fonction cétone dans leur chaîne alcoxyle: Synthèse et réactivité vis-à-vis d'amines secondaires

Reaction of α-bromoisobutyrophenone on quinoline 1-oxide and isoquinoline 2-oxide in the presence of silver perchlorate leads to N-alkoxyquinolinium and isoquinolinium salts bearing a keto group in their alkoxyl chain. On treatment with secondary amines these salts are quantitatively converted to 2-benzoylquinoline and 1-benzoylisoquinoline. This conversion results from a decomposition analogous to the Katritzky mode A of the intermediate isoxazolo[2,3-a]quinolinium or isoquinolinium salts which are first formed by a Proton Abstraction Ring Closure sequence. These tricyclic intermediates have been isolated when 2,2,6,6-tetramethylpiperidine was used.     

Isocyanide addition to pyridinium salts. Efficient entry into substituted nicotinonitrile derivatives

The addition of isocyanides to pyridinium salts is studied. The process takes place efficiently when a carboxamido group is present in the 3 position of the pyridine ring. The outcome of the reaction involves the stabilization of the nitrilium intermediate by the amide, which suffers a mild dehydration, leading regioselectively to beta-cyano-gamma-carbamoyl-1,4-dihydropyridines. In this way, a variety of nicotinamide derivatives were carbamoylated. Extension to quinolinium, isoquinolinium, and N-acylpyridinium salts is also reported. [reaction: see text]     

一步法合成2-芳基咪唑并[2，1-a]异喹啉等杂环化合物

由异喹啉、喹啉或酞腈与α-卤代苯乙酮反应生成的鎓盐在二氢铬酸四吡啶合? 埽═PCD）存在下与乙酸铵反应，可一步法合成咪唑并[2,1-a]异喹啉(2a～2b)、? 溥虿1,2-a]喹啉(4a～4b)或咪唑并[1,2-a]酞腈(6a～6c)衍生物，该方法原料易? 茫从μ跫子诳刂疲佣峁┝艘恢趾铣烧饫嗷衔锏男路椒ā?     

Synthesis of azoxabicyclo[3.3.1]nonanones based on diastereoselective reactions of 1,1-bis(trimethylsilyloxy)ketene acetals with isoquinolines and quinolines

Densely functionalized azoxabicyclo[3.3.1]nonanones were prepared by regio- and diastereoselective condensation of 1,1-bis(silyloxy)ketene acetals with isoquinolinium and quinolinium salts and subsequent regioselective and stereospecific iodolactonization.     

2-Methylpyridinium salts as 1,4-dinucleophiles. II. Westphal condensation with substituted pyridinium substrates

Condensation of α-methylpyridinium, quinolinium and isoquinolinium salts with 1,2-dicarbonyls in the presence of base, yielded quinolizinium derivatives. In an analogous process, α-benzyl derivatives produced 2,3-dihydroindolizin-2-ones by intramolecular cyclisation.     

Acetals of lactams and acid amides. 50. 1-Cyanomethylpyrrolid-2-one diethylacetal in the synthesis of derivatives of pyrrolo[1,2-a]pyrroles

We have synthesized a series of enamines — derivatives of 1-cyanomethyl-2-methy-enepyrrolidine-by reaction of 1-cyanomethylpyrrolid-2-one diethylacetal with compounds having a reactive methylene link. The enamines undergo a Thorpe-Zeigler cyclization in the presence of bases with the formation of pyrrolo [1,2-a]-pyrrole derivatives. The configuration of the enamines obtained were studied using PMR spectroscopy.For Communication 49, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1616–1620, December, 1987.     

Recyclization reactions of heterocycles

The direction of recyclization during hydrazination of isoquinolinium salts is practically independent of the substituent attached to nitrogen and the reaction conditions and leads to compounds with an N-aminoisoquinoline structure.See [1] for communication XIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 961–965, July, 1974.     

Condensed heterocyclic systems with a quaternary nitrogen atom. III. Synthesis of benzimidazo[3,2-b]isoquinolinium perchlorates

Isochromylium cations containing easily detached groupings (NHCOR, NH₂, OCH₃) in the 3 position react readily with o-phenylenediamine. The reaction is accompanied by opening of the benzopyrylium ring and condensation of the resulting compound at one or two amino groups of o-phenylenediamine. Benzimidazo[3,2-b]isoquinolinium salts were synthesized alternatively by acylation of 2-(3,4-dimethoxybenzyl)benzimidazole. The tautomerism of the synthesized N-(2-aminoaryl)isoquinolinium perchlorates was investigated.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 238–243, February, 1976.     

Dual type of reactivity op 1,2-disubstituted dihydro-N-heteroaromatic systems. 11. Aromatization of N-sulfonyl-1,2-dihydroquinolines and isoquinolines containing an α-indolyl or pyrrolyl substituent

When N-sulfonyl-1,2-dihydroquinolines and isoquinolines, containing an indolyl or pyrrolyl substituent at the -position, react with trityl perchlorate, this substituent is split off, and N-sulfonyl quinolinium and isoquinolinium cations and tritylindole or tritylpyrrole are formed. A similar reaction with 2,2,6,6-tetramethyl-1-oxopiperidinium perchlorate proceeds with splitting of hydrogen or retention of the -substituent, which leads to the corresponding -substituted N-sulfonylquinolinium and isoquinolinium cations.For Part 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1516–1518, November, 1986.     

Regio- and diastereoselective dearomatizations of N-alkyl activated azaarenes: the maximization of the reactive sites

An unprecedented base-promoted multi-component one-pot dearomatization of N-alkyl activated azaarenes was developed, which enabled the synthesis of complex and diverse bridged cyclic polycycles with multiple stereocenters in a highly regio- and diastereoselective manner. Besides, we realized the step-controlled dearomative bi- and trifunctionalization of quinolinium salts. These transformations not only achieved the maximization of the reaction sites of pyridinium, quinolinium and isoquinolinium salts to enhance structural complexity and diversity, but also opened up a new reaction mode of these N-activated azaarenes. A unique feature of this strategy is the use of easily accessible and bench-stable N-alkyl activated azaarenes to provide maximum reactive sites for dearomative cascade cyclizations. In addition, the salient characteristics including high synthetic efficiency, short reaction time, mild conditions and simple operation made this strategy particularly attractive.

An unprecedented base-promoted multi-component one-pot dearomatization of N-alkyl activated azaarenes was developed to construct complex and diverse bridged cyclic polycycles with multiple stereocenters in a highly regio- and diastereoselective manner.     

2-Benzopyrylium salts.

The addition of azomethines to 2-benzopyrylium salts, which leads to derivatives of 3,4-dihydroisoquinolinium salts, was observed. An assumption regarding the mechanism of the reaction is expressed on the basis of its stereoselectivity. Dehydrogenation of the compounds obtained to completely aromatic isoquinolinium salts and reduction to tetrahydroisoquinolines were realized.See [1] for Communication 39.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1177–1180, September, 1990.     

Some transformations of dimethylaminovinylpyrimidines

The reaction of enamines of the pyrimidine series with phenyl isothiocyanate, arenediazonium salts, and benzylamine was studied. The corresponding thioamides, pyrimidinylacetaldehydes, and benzylaminovinylpyrimidine were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 559–561, April, 1985.     

Facile Access to Benzothiazole‐Containing Pyrrolo[1,2‐a]quinolines and Pyrrolo[2,1‐a]isoquinolines via Nitrogen Ylides

Quinoline and isoquinoline react with 2‐(bromoacetyl)benzothiazole ( 1 ) in dry benzene to give the corresponding quinolinium and isoquinolinium salts 2 and 10 which undergo base‐mediated [3+2] 1,3‐dipolar cycloaddition with some acetylene and ethylene derivatives to give the corresponding benzothiazole‐containing pyrrolo[1,2‐a]quinoline and pyrrolo[2,1‐a]isoquinoline derivatives.     

Benzo[g]isoquinolinium benzoylmethylids

Stable benzo[g]isoquinolinium methylids were obtained from N-phenacylbenzo[g]isoquinolinium bromides and two of its benzene ring-substituted analogs. The first of these quaternary salts was converted to benzo[g]isoquinolinium dibenzoylmethylid. 3-Benzoyl-l,2-dicarbomethoxynaphth[2,3-g]indolizine was obtained from the same salt with dimethyl acetylenedicarboxylate (via a 1,3-dipolar cycloaddition reaction). Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 806–807, June, 1980     

Benzologs of the thiazolo[3,2-a]pyridinium system

By use of concentrated sulfuric acid rather than hydrobromic acid as the cyclizing medium, good yields of the thiazolo[3,2-a]quinolinium ion and its derivatives may be obtained from α-(2-quinolylthio) ketones or acetals. In the same way, α-(1-isoquinolylthio) and α-(6-phenanthridylthio) ketones afford thiazolo[2,3-a]isoquinolinium and thiazolo-[3,2-f]phenanthridinium salts.     

Indolopyridines with an angular heteroatom. 11. Synthesis of 12-arylidenindolo-[2,1-a]isoquinolinium salts

The condensation of aromatic aldehydes with indolo[2,1-a]isoquinoline in a solution of trifluoroacetic acid yielded a series of 12-arylidenindolo[2,1-a]isoquinolinium trifluoroacetates. Analogous quaternary salts are formed with trichloroacetic and acetic acids as well as upon the reaction of indoloisoquinolinium hydrochloride with p-nitrobenzaldehyde or with p-nitrophenyldiazonium chloride in ethanol.Russian Peoples Friendship University, 117198 Moscow, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 786–790, June, 1999.     

2-Benzopyrylium salts. 29. A new approach to the synthesis of the natural alkaloid salsolidine using 2-benzopyrylium salts

The reaction of 6,7-dimethoxy-1-methyl-2-benzopyrylium salt with ammonia forms the corresponding isoquinoline, and its reaction with methylamine and benzylamine forms mixtures of the corresponding isoquinolinium salts and naphthylamines. The reduction of 2-benzyl-1-methyl-6,7-dimethoxyisoquinolinium perchlorate with sodium tetrahydroborate has given the corresponding tetrahydroisoquinoline, the hydrogenolysis of which has led to salsolidine. The products have been characterized by elementary analyses and IR and PMR spectroscopy.For communication 28 see [1].Scientific-Research Institute of Physical and Organic Chemistry, M. A. Suslov Rostov State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 815–818, November–December, 1985.     

Formation of the pyrroline-N-oxide ring by the reaction of isonitrosoketones with enamines and some conversions of the pyrroline-N-oxides obtained

Compounds containing the pyrroline-N-oxide ring are obtained when isonitrosoketones — 2,6-dihydroxyiminocyclohexanone and -isonitrosoacetophenone — react with enamines. The compounds obtained behave as synthetic equivalents of 1,4-dicarbonyl compounds when undergoing reaction with amines, hydrazine, and hydroxylatnine.Novosibirsk Institute of Organic Chemistry, Siberian Section of the Russian Academy of Sciences (SO RAN) Novosibirsk, 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1055–1061, August, 1996. Original article submitted February 28, 1996.     

Synthesis and spectral-generational characteristics of pentamethylidynecyanine dyes from 1-methyl-3-arylbenzo[f]quinolinium salts

Pentamethylidynecyanine dyes were synthesized by the reaction of 1-methyl-3-(R-phenyl)benzo[f]quinolinium quarternary salts with 1,3,3-triethoxy-1-propene, Pentamethylidynecyanines substituted in the meso position of the polymethine chain were obtained by condensation of these salts with 1-anilino-2-methyl-3-dimethoxy-1-propene hydrobromide. The spectral and generational characteristics of the dyes were determined. It was shown that the presence of a phenyl group in the benzo-[f]quinoline ring of the dyes gives rise to a bathochromic shift of the absorption and generation maxima. The investigated dyes have high generation efficiencies that lie in the 20–30% range and in the 940–1010 nm spectral range.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1523–1527, November, 1982.