A Convenient One Pot Synthesis of 3-Cyano-9-methyl-2-methylthio-4-oxo- 4H- pyrimido[2,1-b] pyrimido [4,5-b] Quinoline and its Reactions with Selected Nucleophiles

3-Amino-8-methyl pyrimido [4,5-b] quinoline (1) in N,N-dimethyl formamide (DMF) and anhydrous potassium carbonate reacted with ethyl-2-cyano-3,3-bismethyl thioacrylate 2 to afford novel heterocyclic compound 3- cyano-9-methyl-2-methylthio-4-oxo-4H-pyrimido [4,5-b] quinoline 3. The latter were further reacted with selected N-, Oand C- nucleophiles such as arylamines, substituted phenols, heterylamines and compounds with an active methylene group.