Trifluoroacetic acid → 2-(4-morpholinyl)-1-(1-piperazinyl)Ethanone

Morpholine (0.22 g, 2.59 mmol), 42-1 (0.61 g, 1.99 mmol) and DIEA (0.33 g, 2.59 mmol) were dissolved in DMF (2 mL) and stirred for 18 hours at room temperature. The DMF was then removed under reduced pressure and the residue partitioned between water and methylene chloride. The methylene chloride was drawn off, dried and evaporated to a solid to afford 42-2. This recovered product was treated with neat trifluoroacetic acid and the excess trifluoroacetic acid evaporated off. The resulting residue was partitioned between methylene chloride and aqueous Na2CO3. The free base did not extract from the aqueous so the aqueous was evaporated to dryness, washed the methanol, and the solids filetred off to afford 42-2. 1H-NMR(CD3OD): 3.69(t, 4H); 3.59 (t, 2H); 3.54(t, 2H); 3.22(s, 2H); 2.83(t, 2H); 2.77(t, 2H); 2.49(t, 4H).