Synthesis,nature of electronic transitions,and absorption spectra of the dye based on 4-(methyl-1-{2-[4-(1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)phenyl]-2-oxoethyl}pyridinium bromide

The reaction of 3-(4-bromoacetylphenyl)-1-methylquinolin-2(1Н)-one with pyridine and 4-methylpyridine has afforded the corresponding pyridinium salts. Condensation of 4-methyl-1-{2-[4-(1-methyl-2-oxo-1,2-dihydroquinolin-3-yl)phenyl]-2-oxoethyl}pyridinium bromide with 4-dimethylaminobenzaldehyde has given a new biscyanine dye, 1-{1-[4-(1,2-dihydro-1-methyl-2-oxo-3-quinolinyl)benzoyl]-2-[4-(dimethylamino)-phenyl]ethynyl}-4-{2-[4-(dimethylamino)phenyl]ethynyl}pyridinium bromide. Its electronic spectrum has been analyzed, and quantum-chemical simulation of spatial and electronic structure of its possible isomers has been performed.     

peri-Naphthylenediamines: XL. Solvatochromism of 1-methyl-4-[2-(1-naphthyl)ethenyl]pyridinium salts, including that containing “proton sponge” residue

A number of 1-methyl-4-[2-(1-naphthyl)ethenyl]pyridinium salts were synthesized by condensation of 1,4-dimethylpyridinium iodide with naphthalene-1-carbaldehydes containing dimethylamino groups in positions 4 and 5. The obtained salts are characterized by negative solvatochromism which is the most pronounced for those possessing 1,8-bis(dimethylamino)naphthalene (“proton sponge”) and 1,2,2,3-tetramethyl-2,3-dihydroperimidine residues.     

Borane complexes of 2-(1-Methyl-1,2,5,6-tetra-hydropyridin-3-yl)benzoxazoles

2-Pyridin-3-ylbenzoxazoles were synthesized by the reaction between 3-pyridinecarboxaldehyde and substituted o-aminophenols in the presence of iodobenzene diacetate. The resulting benzoxazoles 3 were treated with methyl iodide to give the corresponding pyridinium salts 4 which underwent the hydride reduction with sodium borohydride or sodium cyanoborohydride to produce 2-(1-methyl-1,2,5,6-tetrahy-dropyridin-3-yl)benzoxazole borane complex derivatives.     

Preparation of new nitrogen-bridged heterocycles. 56. Syntheses and reactions of 1-[2,2-bis(alkylthio)-1-(ethoxycarbonylacetyl)vinyl]pyridinium salts

The title compounds, readily available from the S-alkylation of pyridinium 1-[alkylthio(thiocarbonyl)](ethoxycarbonylacetyl)methylides with alkyl halides or alkyl bromoacetates, were treated with a base and then a dehydrogenating agent to provide some unique products such as 3-[bis(alkylthio)methylene]-2(3H)-indolizinones and dialkyl 7-methyl-4-oxo-1,4,8,8a-tetrahydro-1,4-thiazino[3,4,5-cd]indolizine-1,5-dicarboxylates. On the other hand, similar reaction of these pyridinium salts in the absence of the dehydrogenating agent afforded alkyl 2-hydroxyindlizine-3-carboxythiolates, whose yields were increased by adding trifluoroacetic acid to the reaction mixture. The structures of some products were confirmed by the X-ray analyses.     

Surface interaction and self-assembly of cyclodextrins with organic dyes

The interaction of seven novel substituted merocyanine dyes, i.e. 1-methyl-4-[2-(3-methoxy-4-hydroxyphenyl)ethenyl)]pyridinium iodide, 1-methyl-4-[2-(3,5-dimethoxy-4-hydroxyphenyl)ethenyl)]pyridinium iodide, 1-methyl-4-[2-(4-dimethylaminophenyl)ethenyl)]pyridinium iodide, their quinoide forms as well as 1-methyl-4-[2-(3-methoxy-4-oxocyclohexadienilydene)ethylidene]-1,4-dihydropyridine, 1-methyl-4-[2-(3,5-dimethoxy-4-oxocyclohexadienilydene)ethylidene]-1,4-dihydropyridine, with α-CD, γ-CD as well as functionalized γ-cyclodextrin phosphate sodium salt is studied by the methods such as UV–Vis and fluorescence spectroscopy, linear-polarized infrared (IR-LD) spectroscopy of oriented colloids in nematic host, ¹H- and ¹³C-NMR spectroscopy, HPLC ESI tandem mass spectrometry, scanning electron and tunneling microscopy, powder X-ray diffraction as well as thermal methods. A formation of the 1D and 2D “supramolecular polymers” with nanosizes is found. The dyes are adsorbed on the CDs surface and form a hexagonal microcrystalline sub-structures. Remarkable fluorescence properties depending of the type of the substituent in the dyes, in solid-state are observed.     

Alkaloids of Siberia and Altai flora: XVIII. Alkyl 2-acetylamino-5-[2-(pyridin-3-yl)vinyl]benzoates in the synthesis of indolizines containing an anthranilic acid ester moiety

Methyl 2-acetylamino-5-[2-(6-methylpyridin-3-yl)vinyl]benzoate reacted with phenacyl bromide to produce quaternary 1-(2-aryl-2-oxoethyl)-2-methyl-5-(4-acetylamino-3-methoxycarbonyl)pyridinium bromides. 1,3-Dipolar cycloaddition of the latter to methyl propynoate and dimethyl but-2-ynedioate gave the corresponding indolizine derivatives containing an anthranilic acid ester moiety. Reactions of acetylenes with N-phenacylpyridinium salts obtained from a diterpene alkaloid derivative, 2-(pyridin-3-yl)vinyl-substituted lappaconitine afforded analogous compounds in which the indolizine fragment is conjugated to the aromatic ring of the alkaloid. 1,3-Dipolar cycloaddition of 1-(2-aryl-2-oxoethyl)-2-methyl-5-(4-acetylamino-3-methoxycarbonyl) pyridinium bromides with methyl propynoate was regioselective.     

Synthesis of 2([Methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl]imino)-1,3-thiazolan-4-ones and Their Mannich Bases

Isoxazolyl chloroacetamides (2) were obtained from 4-amino-3-methyl-5-styrylisoxazoles (1) on reaction with chloroacetyl chloride. Cyclocondensation of 2 with NH₄SCN yielded 2([-methyl-5-(E)-2-aryl-1-ethenyl]-4-isoxazolylimino)-1,3-thiazolan-4-ones(3). Mannich reaction of 3 with formaldehyde and secondary amines gave isoxazolyl thiazolidinone Mannich bases (4 and 5).     

Catalysis of the beta-elimination of HF from isomeric 2-fluoroethylpyridines and 1-methyl-2-fluoroethylpyridinium salts. Proton-activating factors and methyl-activating factors as a mechanistic test to distinguish between concerted E2 and E1cb irreversible mechanisms

Second-order rate constants, k(OH)(N), M(-)(1) s(-)(1), for the beta-elimination reactions of HF with 2-(2-fluoroethyl)pyridine (2), 3-(2-fluoroethyl)pyridine (3), and 4-(2-fluoroethyl)pyridine (4) in OH(-)/H(2)O, at 50 degrees C and mu = 1 M KCl, are = 0.646 x 10(-)(4) M(-)(1) s(-)(1), = 2.97 x 10(-)(6) M(-)(1) s(-)(1), and = 5.28 x 10(-)(4) M(-)(1) s(-)(1), respectively. When compared with the second-order rate constants for the same processes with the nitrogen-methylated substrates 1-methyl-2-(2-fluoroethyl)pyridinium iodide (5), 1-methyl-3-(2-fluoroethyl)pyridinium iodide (6), and 1-methyl-4-(2-fluoroethyl)pyridinium iodide (7), the methyl-activating factor (MethylAF) can be calculated from the ratio k(OH)(NCH)3/, and a value of 8.7 x 10(5) is obtained with substrates 5/2, a value of 1.6 x 10(3) with 6/3, and a value of 2.1 x 10(4) with 7/4. The high values of MethylAF are in agreement with an irreversible E1cb mechanism (A(N)D(E) + D(N)) for substrates 5 and 7 and with the high stability of the intermediate carbanion related to its enamine-type structure. In acetohydroxamate/acetohydroxamic acid buffers (pH 8.45-9.42) and acetate/acetic acid buffers (pH 4.13-5.13), the beta-elimination reactions of HF, with substrates 2 and 4, occur at NH(+), the substrates protonated at the nitrogen atom of the pyridine ring, even when the [NH(+)] is much lower than the [N], the unprotonated substrate, due to the high proton-activating factor (PAF) value observed: 3.6 x 10(5) for 2 and 6.5 x 10(4) for 4 with acetohydroxamate base. These high PAF values are indicative of an irreversible E1cb mechanism rather than a concerted E2 (A(N)D(E)D(N)) mechanism. Finally, the rate constant for carbanion formation from NH(+) with 2 is k(B)(NH)+ = 0.35 M(-)(1) s(-)(1), which is lower than when chlorine is the leaving group ( = 1.05 M(-)(1) s(-)(1); Alunni, S.; Busti, A. J. Chem. Soc., Perkin Trans. 2 2001, 778). This is direct experimental evidence that some lengthening of the carbon-leaving group bond can occur in the intermediate carbanion. This is a point of interest for interpreting a heavy-atom isotope effect.     

Reactions of 2-Amino-4-methyl-6-(2-pyridyl)- and 2-Amino-4-methyl-6-phenyl-7,8-dihydroindazolo[4,5-d]thiazoles with Aldehydes

The reaction of 2-amino-4-methyl-6-(2-pyridyl)-7,8-dihydroindazolo[4,5-d]thiazole, obtained by treating 3-methyl-4-oxo-1-(2-pyridyl)-4,5,6,7-tetrahydroindazole with pyridinium bromide perbromide and then with thiourea, and 2-amino-4-methyl-6-phenyl-7,8-dihydroindazolo[4,5-d]thiazole with 4-bromo-, 4-fluoro-, 4-dimethylamino-, 4-methoxy-, 3,4-dimethoxy-, and 3,4-methylenedioxybenzaldehydes, furfural, pyridinecarbaldehyde, and thiophenecarbaldehyde gave the corresponding Schiff bases. The products of the condensation of these aminothiazoles with cinnamaldehyde, 1-(2-pyridyl)- and 4-chloro-1-(2,4-difluorophenyl)-5-formyl-3-methyl-6,7-dihydroindazoles, 2-formyl-dimedone, and 2-formyl-1,3-indanedione were also obtained.     

An unexpected [2+2]-cycloaddition reaction of 4-methyldithieno-[3,4-b:3′,2′-d]pyridinium iodide with dimethyl acetylenedicarboxylate

An unexpected [2+2]-cycloaddition occured in the reaction of 4-methyldithieno-[3,4-6:3′,2′-d]pyridinium iodide (3)with two equivalents of DMAD, giving 4-(trans-1,2-dicarbomethoxy-2- iodovinyl)-5-methyl-6,7-dicarbomethoxy-4,5-dihydrothieno [23-c]quinoline (4) in 54% yield. 4 is formed via 4-methyl-5-(trans-1,2-dicarbomethoxy-2-iodo-4,5-dihydrothieno [3,4-b:3′,2′-d]pyridine (16), followed by [2+2]-cycloaddition. The primary adduct rearranges via a thiepin to an episulfide which eliminates sulfur to give 4.     

Synthesis and Electronic Transitions of the Dye Based on 1-{2-[4-(3-Hydroxy-2-oxo-2H-chromen-4-yl)phenyl]-2-oxoethyl}-4-methylpyridinium Bromide

Russian Journal of General Chemistry - 4-[4-(2-Bromoacetyl)phenyl]-3-hydroxy-2H-chromen-2-one reacted with pyridine and 4-methylpyridine to give the corresponding quaternary pyridinium salts. The...     

1,2,3,6,7,11b-Hexahydro-4H-pyrimido[2,1-a]isoquinoline-2-ones

The reaction of 1-methyl-3,4-dihydroisoquinolinium salts with acrylamide forms 2-(2-carbamoylethyl)-1-methyl-3,4-dihydroisoquinolinium salts, which are cyclized by the action of bases to form 11b-methyl-1,2,3,6,7,11b-hexahydro-4H-pyrimido[2,1-a]isoquinolin-2-one. Treatment of this compound with iodomethane yields 5, 11b-dimethyl-2-oxo-1,2,3,6,7,11b-hexahydro-4H-pyrimido[2,1-a]isoquinolinium iodide. The 11b-methylpyrimido[2,1-a]isoquinolin-2-one enters into condensation with aromatic aldehydes, forming the corresponding styryl compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 499–502, April, 1993.     

Alkyl (E,Z)-2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-dimethylaminopropenoates in the synthesis of fused pyrimidinones. A facile route to 3-aminoazino-4H-pyrimidin-4-ones

Alkyl (E,Z)-2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-dimethylaminopropenoates 1a,b react with het-eroarylamines 2 to give alkyl 2-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-3-heteroarylaminopropenoates 3-13 . These were cyclized into fused 3-(2-benzoyl-2-ethoxycarbonyl-1-ethenyl)amino-4H-azolo- (or azino)-pyrim-idin-4-ones 14-18 . 2-Benzoyl-2-ethoxycarbonyl-1-ethenyl group can be easily removed from 3-(2-benzoyl-2-ethoxycarbonyl-1-emenyl)amino-8-memyl-4H-pyrido[1,2-a]pyrimidin-4-one ( 14 ) to give 3-amino-8-methyl-4H-pyrido[1,2-a]pyrimidin-4-one ( 19 ). The structure of 1a was confirmed by X-ray analysis.     

吡啶基团的对称性和离子化对分子双光子吸收截面的影响

采用超快速激光光谱方法研究了含吡啶基团的四个联苯乙烯衍生物及两个杂环分子(A: 4,4’-二(2-(4-吡啶基)乙烯)联苯; B: 4,4’-二(2-(2-吡啶基)乙烯)联苯; C: 1-甲基-4-(2-(4’-(2-(4-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; D: 1-甲基-2-(2-(4’-(2-(2-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; E: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基吡啶碘盐; F: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基喹啉碘盐)的结构-性能关系. 实验结果显示双光子吸收截面最大的是分子E, 高达617.3 GM; 最小的是分子B, 为19.3 GM(1 GM=10^-50 cm⁴·s·photon^-1). 实验研究结果表明, 分子中吡啶基团的对称性及其离子化对分子双光子吸收截面起很重要的作用; 进一步用理论计算证实了以上实验结论并对其机制进行了分析讨论.     

Homologous SNV Reaction: Synthesis of l‐Methyl‐4‐[4′‐phenylsulfonyl‐1′,3′‐butadienyl]pyridinium Iodide and Its Reactivity with Thiol Groups Giving Rise to the Chromophoric Thioether

Thioether 4‐[(1′E,3′E)‐4′‐phenylsulfanyl‐1,3′‐butadienyl]pyridine 8 and sulfone 4‐(4′‐phenylsulfonyl‐1′,3′‐butadienyl)pyridine 14 were prepared by reaction of the carbanions derived from allylic thioether or allylic sulfone with isonicotinaldehyde. The reaction with the sulfonyl carbanion occurred at the α position and on heating the alcolate gave the dienic sulfone 14 . The corresponding pyridinium iodide 10 and 15 were prepared by reaction with methyl iodide, respectively, on pyridine derivates 8 and 14 . The dienic pyridinium thioether 10 showed a long wavelength absorption band centered at 420 nm. The reaction of dienic pyridinium sulfone 15 with thiophenol gave the dienic pyridinium thioether 10 by a nucleophilic vinylic substitution. The reaction of sulfone 15 with glutathione was of second order and the rate constant was 8.5 M^?1s^?1 at 30°C and pH 7, about 500 times smaller than the rate constant observed with (E)‐1‐methyl‐4‐(2‐methylsulfonyl‐1‐ethenyl)pyridinium iodide 1 . The dienic pyridinium thioether 10 was a negative solvatochrome.     

Syntheses, spectroscopic and molecular quadratic nonlinear optical properties of dipolar ruthenium(II) complexes of the ligand 1,2-phenylenebis(dimethylarsine)

Six new complex salts trans-[Ru(II)Cl(pdma)2L][PF6]n [pdma = 1,2-phenylenebis(dimethylarsine); L = (E,E,E)-1,6-bis(4-pyridyl)hexa-1,3,5-triene (bph), n= 1, 5; L =N-methyl-4-[(E)-2-(4-pyridyl)ethenyl]pyridinium (Mebpe+), n= 2, 7; L =N-methyl-4-[(E,E)-4-(4-pyridyl)buta-1,3-dienyl]pyridinium (Mebpb+), n= 2, 8; L =N-methyl-4-[(E,E,E)-6-(4-pyridyl)hexa-1,3,5-trienyl]pyridinium (Mebph+), n= 2, 9; L = bis(4-pyridyl)acetylene (bpa), n= 1, 10; L =N-methyl-4-[2-(4-pyridyl)ethynyl]pyridinium (Mebpa+), n= 2, 11] have been prepared. The electronic absorption spectra of 5 and 7-11 display intense, visible metal-to-ligand charge-transfer (MLCT) bands, with lambdamax values in the range 434-492 nm in acetonitrile. Cyclic voltammetric studies reveal reversible Ru(III/II) waves with E(1/2) values in the range 1.06-1.15 V vs. Ag-AgCl, together with irreversible L-based reduction processes. Along with a number of previously reported related compounds (B. J. Coe et al., J. Chem. Soc., Dalton Trans., 1996, 3917; 1997, 591; 2000, 797), salts 5 and 7-11 have been investigated by using Stark (electroabsorption) spectroscopy in butyronitrile glasses at 77 K. These studies have afforded dipole moment changes Deltamu12 for the MLCT transitions which have been used to calculate molecular static first hyperpolarizabilities beta0 according to the two-state equation beta0= 3Deltamu12(mu12)2/(Emax)2 (mu12 = transition dipole moment, Emax = MLCT energy). MLCT absorption and electrochemical data show that a trans-[Ru(II)Cl(pdma)2]+ centre is considerably less electron-rich than a [Ru(II)(NH3)5]2+ unit. Although the beta0 responses of the pdma complexes are only a little smaller than those of their [Ru(II)(NH3)5]2+ analogues, this result is partly attributable to unexpected changes in the relative mu12 values on freezing. Thus, substantial increases in mu12 for the arsine compounds act to partially offset the beta0-decreasing influence of their higher Emax values when compared with the analogous pentaammine species. Single crystal X-ray structures have been obtained for the salts 1(.)2.5MeCN, 4(.)2MeCN, 7 and 11, but only 1(.)2.5MeCN adopts a non-centrosymmetric space group (Fdd2) such as may show bulk NLO effects.     

The structure dependent electrochemical-response of novel 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide SAMs on an au electrode

The 1-(4-mercaptobutyl)-4-(2-ferrocenylvinyl)pyridinium bromide (1-HS(CH2)(4)-4-[(E)-FcCH=CH]C5H4N)+Br- and its hydrogenated product [1-HS(CH2)(4)-4-(-FcCH2CH2)C5H4N]+Br- were synthesized and assembled on an Au electrode to form self-assembled monolayers which showed a structure-dependent electrochemical-response in phosphate buffer aqueous solutions (pH = 7).     

Regioselectivity of cyclization of 1-(6-methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-arylthiosemicarbazides by treating with methyl iodide and dicyclohexylcarbodiimide

1-(6-Methyl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)-4-arylthiosemicarbazides treated with methyl iodide in the presence of sodium acetate in ethanol convert into 6-methyl-3-arylamino[1,2,4]-triazolo[4,3-b][1,2,4]triazin-7(1H)-ones. In reaction with dicyclohexylcarbodiimide 6-methyl-3-arylamino[1,2,4]triazolo[3,4-c][1,2,4]triazin-5(1H)-ones were obtained which at heating in alcohol solution in the presence of sodium acetate or at 262–272°C underwent the Dimroth rearrangement to give 3-methyl-7-arylamino[1,2,4]triazolo[5,1-c][1,2,4]-triazin-4(8H)-ones.     

A Facile Synthesis of 3-(21Hydroxybenzoyl)-1-Methyl-2(1H)-Pyridinones From Benzopyrano [2,3-b] Pyridines

The methyl iodide salts of benzopyrano[2,3-b]pyridines have been ring-opened to give 3-(2¹-hydroxybenzoyl)-1-methyl-2(1H)-pyridinones in high yield.     

A simple and efficient route for the synthesis of novel isoxazolyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones

A new, simple and efficient method for the synthesis of novel isoxazolyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones is described by the intramolecular ipso-cyclization of 5-[(E)-2-(4-methoxyphenyl)-1-ethenyl]-3-methyl-4-nitroisoxazole with nitriles. In presence of 5-[(E)-2-(4-methoxyphenyl)-1-ethenyl]-3-methyl-4-nitroisoxazole, a variety of nitriles underwent the intramolecular ipso-cyclization smoothly, affording title compounds in moderate to good yields.