反応 #6330

反応方程式

Acetic anhydride

(±) N-[(9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide

methanesulfonic anhydride

→

title compound

N-[(7-Acetyl-9,9a-dihydro-3-oxo-1H,3H-oxazolo-[3,4-a]indol-1-yl)methyl]acetamide

溶媒

methylene chloride

methane sulfonic acid

反応条件

後処理

1. 1
   温度to warm slowly to 20°-25° overnight
2. 2
   workup.ADDITIONThen the mixture is added
3. 3
   抽出is extracted with ethyl acetate (4×3 ml)
4. 4
   洗浄The combined organic layers are washed with saturated aqueous sodium bicarbonate (2 ml), saline (1 ml)
5. 5
   乾燥dried over anhydrous potassium carbonate
6. 6
   濃縮concentrated to an oil
7. 7
   抽出Extraction of the appropriate band and concentration

実験手順

Acetic anhydride (53 μl) is slowly added to a mixture of (±) N-[(9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide (X diastereomer A, EXAMPLE 18, 21 mg), methanesulfonic anhydride (33 mg) in methylene chloride (0.1 ml) and methane sulfonic acid (0.50 ml) at 0°. The temperature is kept below 15° for 3 hr, then allowed to warm slowly to 20°-25° overnight. Then the mixture is added to crushed ice (0.5 ml). After the ice has melted the mixture is extracted with ethyl acetate (4×3 ml). The combined organic layers are washed with saturated aqueous sodium bicarbonate (2 ml), saline (1 ml), dried over anhydrous potassium carbonate and concentrated to an oil. The oil is place on a silica prepratory plate (14 cm×17.5 cm, 250μ) and developed in methanol/methylene chloride (5/95, 3×). Extraction of the appropriate band and concentration give the title compound.

出典