- Regioselective Azidation of 2,4-Dichloroquinolines
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Reactions of 2,4-dichloroquinolines (2a-f) with sodium azide in DMF lead either regioselectively to 4-azido-2-chloroquinolines (3a-f) or with excess of sodium azide and catalysts to 5-azido-tetrazoloquinolines (4a-f). 2,4-Dichloroquinolines (2g-i) having electron donating substituents in 3-position react with sodium azide in DMF to a mixture of 4-azido-2-chloroquinolines (3g-i) and 5-chlorotetrazoloquinolines (5g-i).When the reaction of the 2,4-dichloroquinolines (2a-i) with sodium azide is carried out in ethanol with addition of methanesulfonic acid, regioselectively 5-chloro-tetrazoloquinolines (5a-i) are obtained.Structural assignments of 3 and 5 have been carried out by 13C-NMR spectra, IR spectra and degradation reactions of the azido- and tetrazolo group to aminoquinolines (7 and 10) via iminophosphoranes (8 and 9).It could be shown that in 2-azido/tetrazolo-quinolines (4 and 5) the tetrazole ring structure is the dominant species.
- Steinschifter, Waltraud,Stadlbauer, Wolfgang
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- Efficient synthesis, fluorescence and DFT studies of different substituted 2-chloroquinoline-4-amines and benzo[g][1,8]naphthyridine derivatives
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An efficient and single step strategy for synthesizing new functionalized benzo[b][1,8]naphthyridine derivatives is presented. Benzo[g][1,8]naphthyridines have been synthesized by the condensation of substituted 2-chloroquinoline-3-carbaldehydes with various 2-chloroquinoline-4-amines, 1H-Indazole-6-amine in basic medium. The electro luminescence and photophysical properties of a series of benzo[g][1,8]naphthyridines 5(a–d), 6(a–d) and 2-chloroquinoline-4-amines 3(a–f) are reported and investigated with the aim of arriving at good fluorescent materials. Moreover, the effect of electron donor-acceptor substituent on fluorescence properties of all molecules has been investigated along with their fluorescent quantum yields. Furthermore we analyzed for band gap energy associated with HOMO-LUMO, through density functional (DFT M06-HF) studies. The experimental observations are in close agreement with the theoretical calculation. All the synthesized compounds were identified on the basis of their NMR, Mass spectral data analyses.
- Magesh Selva Kumar,Vijaya Pandiyan,Mohana Roopan,Rajendran
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