反应详情

A solution of the product from Example 7 (0.2 g) in dichloromethane (15 ml) was treated with N,N-diisopropylethylamine (0.11 g) followed by acetic anhydride (0.16 g) and the resultant mixture was stirred at room temperature for 4 hours. The mixture was washed with a saturated solution of aqueous sodium bicarbonate (15 ml) and the organic layer concentrated in vacuo. The residue was dissolved in a 0.1 molar solution of sodium methoxide in methanol (20 ml) and the solution allowed to stand for 2 hours at room temperature. Following concentration in vacuo the residue was acidified by careful addition of acetic acid, the mixture was again concentrated in vacuo and he residue azeotroped with toluene (3×100 ml). Purification by chromatography (SiO2 methanol:chloroform 1:24 as eluant) gave the title compound (0.12 g).

1. washThe mixture was washed with a saturated solution of aqueous sodium bicarbonate (15 ml)
2. concentrationthe organic layer concentrated in vacuo
3. dissolutionThe residue was dissolved in a 0.1 molar solution of sodium methoxide in methanol (20 ml)
4. concentrationconcentration in vacuo the residue
5. additionwas acidified by careful addition of acetic acid
6. concentrationthe mixture was again concentrated in vacuo and he residue
7. customazeotroped with toluene (3×100 ml)
8. customPurification by chromatography (SiO2 methanol:chloroform 1:24 as eluant)