- Functionalization at C2, C3, and C4 of quinolines: Discovery of water-soluble betaine dyes of C3 quinolinium derivatives with solvatochromic and pH-sensitive properties
-
During functionalization at C2, C3, and C4 of quinoline, we came across a one-step metal free synthesis of C3 quinolinium derivatives of mesomeric betaine dyes. Some mesomeric betaine dyes had solvatochromic properties, and were sensitive to pH and solvates in the water. Certain betaine dyes had different properties in acidic and basic environments; the reversible interconversion between yellow (neutral or basic condition) and colorless (acidic condition) forms of the dye occurs by pH change. The changes in UV absorbance intensities of the dyes in the presence of cyclodextrins indicated the inclusion complex formation between cyclodextrins and dyes. The betaine dyes were partially dissolved in water due to the presence of positive and negative charges in the molecule. These betaine dyes did not exhibit cytotoxic activity, hence may be used in biological research.
- Aree, Thammarat,Kesornpun, Chatchai,Kittakoop, Prasat,Mahidol, Chulabhorn,Ruchirawat, Somsak,Sangher, Sasithorn
-
-
Read Online
- Driving Force Dependence of Photoinduced Electron Transfer Dynamics of Intercalated Molecules in DNA
-
A series of acridinium, quinolinium, and phenanthridinium ions (9-substituted-10-methylacridinium (AcrR+, R = H, PrI, and CH2Ph), 3-substituted-1-methylquinolinium (RQuH+, R = CN and Br), and 5-methylphenanthridinium (5-MePhen+) perchlorate salts) are shown to be intercalated into the DNA double helix from calf thymus. The one-electron reduction potentials (Ered0) of these intercalates have been determined in the absence and presence of DNA by both cyclic voltammetry and second harmonic ac voltammetry. The E0red values of intercalators are shifted in a positive direction by intercalation into the DNA double helix. The one-electron oxidation potential (E ox0) of ethidium bromide, which is known to be intercalated into DNA, is also shifted in a positive direction by the intercalation. The wide range of E0red values of intercalators thus determined in the presence of DNA allows us to examine the exact driving force dependence of the rates of photoinduced electron transfer from the singlet excited state of ethidium bromide to the intercalators in DNA for the first time. The resulting data were evaluated in light of the Marcus theory of electron transfer to determine the reorganization energy and the electron coupling matrix element in DNA.
- Fukuzumi, Shunichi,Nishimine, Mari,Ohkubo, Kei,Tkachenko, Nikolai V.,Lemmetyinen, Helge
-
-
Read Online
- Heteroaromatic cation-based chromophores: Synthesis and nonlinear optical properties of Alkynylazinium salts
-
A variety of alkynylazinium cationic (D-π-A+) chromophores were prepared in good yields by the reaction of bromoazinium (pyridinium, quinolinium, and isoquinolinium iodides) with alkynes under Sonogashira conditions. The analysis of the experimentally recorded spectra is supported by quantum chemical calculations using restricted configuration interaction and density functional methods. First-order hyperpolarizabilities of (D-π-A +) azinium-based cations as a new class of second-order nonlinear optical (NLO) chromophores were also studied by hyper-Rayleigh scattering experiments and computational procedures. Copyright
- Caneque, Tatiana,Cuadro, Ana M.,Alvarez-Builla, Julio,Perez-Moreno, Javier,Clays, Koen,Marcelo, Gema,Mendicuti, Francisco,Castano, Obis,Andres, Jose L.,Vaquero, Juan J.
-
supporting information; experimental part
p. 6323 - 6330
(2011/01/13)
-
- Kinetic and thermodynamic control of pseudobase formation from C-3 substituted 1-methylquinolinium cations
-
The kinetic and thermodynamic control of pseudobase formation from 3-W-1-methylquinolinium cations has been studied for a variety of substituents (W).Spectral data indicate that, in both aqueous and methanolic solution, the C-2 pseudobases predominate at equilibrium for W=H and Br, while the C-4 pseudobases are thermodynamically preferred species for W=CONH2, CO2CH3, CN, and NO2.Stopped-flow studies indicate that in all cases the C-2 pseudobases are the kinetically-controlled products upon basification of the aqueous solutions of these cations.Equilibrium constants (pKR+) have been measured for pseudobase formation at both C-2 and C-4 for each W in all cases where they are experimentally accessible.Substituent effects upon pK2R+ correlate with ?m for W, while pK4R+ depends upon ?-p.These substituent effects allow the prediction of pK2R+ = 15.4 and pK4R+ = 17.4 for the 1-methylquinolinium cation.Rates of C-2 to C-4 pseudobase equilibration have been measured in all cases where the latter species is thermodinamically more stable.These kinetic data allow the evaluation of rate constants for C-4 pseudobase equilibration with each cation.In all cases except W=CN, C-2 pseudobase formation is complete within the mixing time of the stopped-flow instrument.
- Bunting, John W.,Fitzgerald, Norman P.
-
p. 1301 - 1307
(2007/10/02)
-
- Regioselectivity of Hydride Transfer to and between NAD+ Analogues
-
The reaction of 1-methyl- or 1-benzylquinolinium compounds, also bearing an electron-withdrawing substituent in the 3-position, with NaBH4, gives mixtures of the corresponding 1,2-dihydroquinolines and 1,4-dihydroquinolines in which the 1,2-dihydro derivatives usually predominate.The 1,2-derivatives can be isolated.The 1,2-isomers react with the quinolinium salts, giving the 1,4-isomers and regenerating quinolinium salts.This bimolecular isomerization can be used to convert a mixture of isomers to the 1,4-isomer on a preparative scale. 3-Cyano-1,2-dihydro-1-methylquinoline also isomerizes to the 1,2-isomer in the crystalline solid.The major first product of NaBH4 reduction of 3-(aminocarbonyl)-1-benzylpyridinium ion is the 1,6-dihydro derivative.This also isomerizes to the 1,4-dihydro compound in the presence of the pyridinium ion.Reduction of quinolinium derivatives with Na2S2O4 or a dihydropyridine directly produces the 1,4-isomer predominantly.Reduction of 3-(aminocarbonyl)-1-benzylpyridinium ion with Na2S2O4 in D2O gives the 1,4-dihydro derivative, but 8percent of the deuterium is in the 2-position; presumably by reversible isomerization.This deuterium redistribution may have important consequences for the interpretation of isotope effects.
- Roberts, R. M. G.,Ostovic, D.,Kreevoy, M. M.
-
p. 2053 - 2056
(2007/10/02)
-