反应详情

The product of Step E (55 g, 181 mmoles) was dissolved in methanol. 100 ml of ammonium hydroxide were added, the solution was refluxed for 3 hours and then stirred at room temperature for 15 hours. The methanolic solution was brought to pH7 using concentrated aqueous hydrochloric acid and diluted with ethyl acetate. The organic layer was washed several times with water and brine, dried over MgSO4 and concentrated to dryness to give an oily brown residue which was recrystallized from methyl tert-butyl ether to afford 33 g of the title compound, m.p. around 187° C.

1. temperaturethe solution was refluxed for 3 hours
2. washThe organic layer was washed several times with water and brine
3. dry with materialdried over MgSO4
4. concentrationconcentrated to dryness
5. customto give an oily brown residue which
6. customwas recrystallized from methyl tert-butyl ether