反应详情

To a mixture of sodium hydride (3.13 g, 130.5 mmol) in tetrahydrofuran at 0° C. was added methanol (5.3 mL, 130.5 mmol) and allowed to warm to room temperature. The reaction was cooled to 0° C. and 2-bromo-2-methylpropionyl bromide (5.4 mL, 43.5 mmol) was added. After warming to room temperature, the reaction was heated to 45° C. for 42 hours and then cooled to room temperature. The resulting mixture was filtered through diatomaceous earth with ether wash and the solvent was distilled off. The pot residue was partitioned between ether and 1N hydrochloric acid. The organic layer was dried (magnesium sulfate), filtered and concentrated to give methyl 2-methoxy-2-methylpropionate and 2-methoxy-2-methylpropionic acid (2.47 g). This mixture of products was treated with methanolic sodium hydroxide, using a similar procedure to that described in Example 111b and distillation, the title compound was obtained as a colorless oil (650 mg, 12.6%), bp 85°-95° C./20 mm; MS(CI): 119(M+H); H-NMR (300 MHz, DMSO-d6): 1.29(s, 6H), 3.14(s, 3H), 12.52(s, 1H).

1. temperatureThe reaction was cooled to 0° C.
2. temperatureAfter warming to room temperature
3. temperaturethe reaction was heated to 45° C. for 42 hours
4. temperaturecooled to room temperature
5. filtrationThe resulting mixture was filtered through diatomaceous earth with ether
6. washwash
7. distillationthe solvent was distilled off
8. customThe pot residue was partitioned between ether and 1N hydrochloric acid
9. dry with materialThe organic layer was dried (magnesium sulfate)
10. filtrationfiltered
11. concentrationconcentrated