Pyrazine derivatives R 0550New Method for the Anellation of the Pyridine Fragment to Azines. -An intramolecular reaction is used as key step for the anellation of a pyridine ring to quinoxalines leading to compounds of type (III) which are fragments of many highly active antibacterial drugs. -(CHARUSHIN*, V. N.; BOGUSLAVSKY, A. M.; PONIZOVSKY, M. G.; KODESS, M. I.; CHEKHLOV, A. N.; MKOYAN, S. G.; ALDOSHIN, S. M.; Russ.