- Regioselective N-alkylation of some imidazole-containing heterocycles and their in vitro anticancer evaluation
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Imidazole-containing heterocycles: Imidazopyridines, imidazopyrimidines and imidazopyra-zines can exist more tautomeric forms than benzimidazoles. Their regioselectivities were determined for N-alkylations with 4-fluorobenzyl bromide under basic conditions (K2CO3) in DMF. We observed that, regioisomers were mainly formed as a mixture in this reaction and N-benzylation occurs at a higher ratio on six membered heterocycles. Their structural assignments were made with the use of two-dimensional 1H–1H NOE (nuclear overhauser effect spectroscopy, NOESY). Complementary structural information was provided by 2D-HMBC spectra of the compounds. Synthesized compounds were tested for in vitro cytotoxic activities against Human colon cancer cell line (HCT-116) and leukemia cell lines (K562 and HL-60) by MTT test. Among them, imidazopyridine analogue 10, bearing bromine atom at the C-6 position of the pyridine moiety, gave the lowest IC50 value with 6–7 μg/mL against all three cancer cell lines.
- Karaaslan, Cigdem,Doganc, Fatima,Alp, Mehmet,Koc, Asli,Karabay, Arzu Zeynep,G?ker, Hakan
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- Imidazopyridine derivatives, preparation method and pharmaceutical compositions containing same
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Compounds of formula (I): wherein: R1 represents hydrogen, halogen, alkyl, polyhaloalkyl, cyano, nitro, hydroxycarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl or dialkylaminocarbonyl, R2 represents hydrogen, alkyl, an opt
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(2008/06/13)
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- The ortho effect in pyridines. Part XI(1). Substituent effects on basicity of 2- and 4-substituted 3-aminopyridines
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The substituent effects on the pKa values corresponding to the first protonation site of thirty 2- and 4-substituted 3-aminopyridines have been studied.It was found that the relative localized and delocalized effects are apparently sensitive to the variation of substituent position in the pyridine ring.An interaction of the 2-substituent with the protonation centre has mainly inductive character, whereas, the pKa values of 4-substituted 3-aminopyridines are highly affected by through-resonance.The steric effect was found to be insignificant.Keywords: substituent effects / 2- and 4-substituted 3-aminopyridines / basicity
- Rasala, D.
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