P. Kolar et al., TRANSFORMATIONS OF THE PYRIDO[1,2-A]PYRAZINE RING-SYSTEM INTO IMIDAZO[1,2-A]PYRIDINES, IMIDAZO[1,2-A]PYRIMIDINES AND 2-OXA-6A,10C-DIAZAACEANTHRYLENES, Journal of heterocyclic chemistry, 33(3), 1996, pp. 639-642
Transformations of methyl -(1-methoxycarbonyl-4-oxo-4H-pyrido[1,2-a]py
razin- 3-yl)acrylate with some cyanomethylenecarbonyl group containing
compounds or cyanamide into imidazo[1,2a]pyridines, imidazo[1,2-a]pyr
imidines and 2-oxa-6a,10c-diazaaceanthrylenes are described.