aza-Annulation of Tetrahydroisoquinoline Derived Enamines: Efficient and Convergent Routes to Novel Functionalized Benzo[a]quinolizin-4-ones and Pyrimido[6,1-a]isoquinoline Derivatives - Chakrabarti, Sriparna; Srivastava, Manish C; Ila, Hiriyakkanavar; Junjappa, Hiriyakkanavar (Synlett, 2003)