Synthesis and reactivity of cyanomethyl 2-amino-4-methylthiazolyl ketone. A facile synthesis of novel pyrazolo[5,1-c]1,2,4-triazine, 1,2,4-triazolo[5,1-c]1,2,4-triazine, 1,2,4-triazino[4,3-a]benzimidazole, pyridazine-6-imine and 6-oxopyridazinone derivatives