W. Mederski, D. Kux, M. Knoth
Apr 1, 2003
Citations
0
Influential Citations
8
Citations
Journal
Heterocycles
Abstract
5-Chloropyrido[3,4-b]pyrazines were prepared from 1,2-dicarbonyl compounds and 2-chloro-3,4-diaminopyridine. Condensation of unsymmetrical glyoxals provided a mixture of two regiosiomers with 2-substituted pyrido[3,4-b]-pyrazines as the major product. The regiochemistry was unambiguously assigned by 2D-NMR experiments. C-C- and C-N coupling reactions of 5-chloro or 5-oxo intermediates afforded the corresponding C-5 or N-6 substituted derivatives.