Potassium Phosphate, Tribasic → 1-(5-(tetrahydro-2H-pyran-4-yl)-3-methyl-1-benzofuran-2-yl)-2-methylpropan-1-one

Temperature

80 °C

1-(5-Hydroxy-3-methyl-1-benzofuran-2-yl)-2-methylpropan-1-one (1.0 g) synthesized in the above-mentioned (1) was dissolved in N,N-dimethylforamide (20 mL) and was added potassium phosphate (1.3 g) and tetrahydro-2H-pyran-4-yl 4-methylbenzenesulfonate (2.8 g) at room temperature. The reaction mixture was stirred at 80° C. for 4 hr, then again added potassium phosphate (1.3 g) and tetrahydro-2H-pyran-4-yl 4-methylbenzenesulfonate (2.8 g). After being stirred for 12 h at 80° C., then cooled to room temperature and quenched with water. The mixture was extracted with diethyl ether then washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:4, volume ratio) to give 1-(5-(tetrahydro-2H-pyran-4-yl)-3-methyl-1-benzofuran-2-yl)-2-methylpropan-1-one (1.1 g, 78%) as a colorless oil. Obtained oil (1.1 g) was dissolved in tetrahydrofuran (15 mL) and methanol (1 mL), and sodium borohydride (90%, 0.30 g) was added to the solution under ice-cooling. The ice bath was removed, and the reaction mixture was stirred at room temperature for 1 hr then ice-cooled again, and water (5 mL) and 1N hydrochloric acid (15 mL) were carefully added to the mixture, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give 1-(5 (tetrahydro-2H-pyran-4-yl)-3-methyl-1-benzofuran-2-yl)-2-methylpropan-1-ol (0.71 g, 65%) as a pale-yellow oil. The obtained oil was dissolved in tetrahydrofuran (15 mL), and thionyl chloride (0.30 mL) was added to the solution at room temperature. The reaction mixture was stirred at room temperature for 30 min then ice-cooled, and saturated aqueous sodium hydrogen carbonate solution (20 mL) was carefully added to the mixture. The reaction mixture was stirred for 10 min, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was dissolved in dimethylacetamide (15 mL), sodium iodide (0.52 g), sodium carbonate (0.35 g) and ethyl 3-{[(4-aminophenyl)carbonyl](methyl)amino}propanoate (0.58 g) synthesized in Example 2(2) were added to the mixture, and the mixture was stirred at 70° C. for 4 hr. After allowing to cool, water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The extract was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:1, volume ratio) to give ethyl 3-(methyl{[4-({2-methyl-1-[3-methyl-5-(tetrahydro-2H-pyran-4-yloxy)-1-benzofuran-2-yl]propyl}amino)phenyl]carbonyl}amino)propanoate (0.54 g, 46%) as a yellow oil. The obtained oil was dissolved in ethanol (3 mL), 1N aqueous sodium hydroxide solution (3.0 mL) was added to the solution at room temperature, and the mixture was stirred at room temperature for 0.5 hr. Ethanol was evaporated under reduced pressure, and 1N hydrochloric acid (3.0 mL) was added to the residue. The precipitate was washed with water to give the title object compound (0.53 g, 98%) as a colorless solid.

1. stirringAfter being stirred for 12 h at 80° C.
2. temperaturecooled to room temperature
3. customquenched with water
4. extractionThe mixture was extracted with diethyl ether
5. washthen washed with saturated brine
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:4, volume ratio)

ORD record

ord-3f734b331ec24266b4167bb2212cc97c

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08436043B2