Mild and Direct Access to 7-Substituted-4-trifluoromethylpyrimido[1,2-b]pyridazin-2-one Systems. -Aniline and diisopropylamine are found to be unreactive in the transformation with (VI). The reaction of (I) to (VIIIa) or (Xb) or (XIIa), resp., is also performed following a one-pot procedure giving virtually equal yields of products. -(PETRIGNET, J.; THIERY, E.; SILPA, L.; ABARBRI*, M.; Synthesis 46 (2014) 7, 947-954, http://dx.doi.org/10.1055/s-0033-1340664 ; Lab. Infect. Sante Publique, Fac. Sci. Tech., Univ. Francois-Rabelais, F-37200 Tours, Fr.; Eng.) -F. Schill 38-175