Synthesis of Isomeric Enamine Derivatives of Fused Cycloalkeno Thieno[2,3-d]pyrimidin-4(3H)-ones. Stereoelectronic Effect on the Regioselectivity - Lilienkampf, Annamaria; Heikkinen, Sami; Mutikainen, Ilpo; Wähälä, Kristiina (Synthesis, 2007)