Compound 1 (0.879 g, 0.0036 mol ) was dissolved in methylisobutylketone (MIBK) (80 mL). 4-(2-Methoxyphenyl)piperidin-4-ol (1.123 g, 0.0054 mol) and K2CO3 (1.99 g, 0.0145 mol) were added. The resulting mixture was stirred at reflux temperature for 12 h. The reaction mixture was filtered and the solvent evaporated in vacuo. The residual oil was purified on a silica gel column (Eluent: CH2Cl2 /ethanol/25% NH4OH (aq) (92.75:7:0.25)). The product was acidified with 2M HCl(g) in diethylether, to give the title compound 1.1 g (68%). M.p. decomposes at 228° C.
