Pyrazine derivatives R 0550The Regioselective Synthesis of 2H-Pyrido[2,3-b]pyrrolo[2,3-e]pyrazin-2-one. -(JAMROZY, K.; SZYMONIAK, K.; OSTROWSKA*, K.; Heterocycles 75 (2008) 9, 2275-2282; Dep. Org. Chem., Jagiellonian Univ., PL-30-060 Krakow, Pol.; Eng.) -D. Singer