A suspension of the compound of Example 20 (70 mg) and potassium carbonate (142 mg, Kokusan Chemical) in N,N-dimethylformamide (1.5 ml) was added with 2-(2-bromoethoxy)tetrahydro-2H-pyran (254 μl, Aldrich) and stirred at room temperature for 48 hours. The reaction mixture was added with acetone (10 ml), and insoluble matters were separated by filtration. Then, the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (chloroform:methanol=6:1) to obtain the title compound (40 mg).
