Scheme 3.

^a Synthesis of compounds 28 – 32 and 40-47

^aReagents: (a) K₂CO₃, DMSO, 110 °C 2-5 h; (b) Fe, NH₄Cl, EtOH, H₂O, 75 °C; (c) NaNO₂, conc HCl, CuCl, 80 °C, 1h; (d) CH₃B(OH)₂, Cu(OAc)₂, pyr, dioxane, reflux; (f) Acrylonitrile, PdCl₂(PPh₃)₂, Et₃N, DMF, 140 °C, 2 h; (g) BBr₃, CH₂Cl₂, -78 °C, overnight or LiCl, DMF 160 °C, overnight; (h) DIAD, bromoethanol, Ph₃P, THF, rt, overnight; (i) 3-benzoylpyrimidine-2,4(1H,3H)-dione, K₂CO₃, DMF, rt, overnight then NH₄OH, MeOH, rt.