Reaktion #6328

Reaktionsgleichung

acetic anhydride

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

methane sulfonic acid

acetic anhydride

sodium bicarbonate

sodium bicarbonate

→

material

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

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter this time the mixture is cooled in an ice bath
2. 2
   workup.ADDITIONis added
3. 3
   ExtraktionThe mixture is then extracted with methylene chloride (5×, 20 ml total)
4. 4
   ExtraktionThe combined extract layers

Vorschrift

A mixture of (±) (1S,9aS/1R,9aR) N-[(9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide (X diastereomer B, EXAMPLE 11, 8 mg), methane sulfonic acid (0.5 ml), and acetic anhydride (10 μl) is stirred in methylene chloride (0.2 ml) from 0° to 20° for 19.5 hours. After this time the mixture is cooled in an ice bath and additional acetic anhydride (10 μl) is added. The mixture is stirred for one hour then added to a small amount of ice and saturated aqueous sodium bicarbonate (7 ml) is added, then solid sodium bicarbonate is added until alkaline. The mixture is then extracted with methylene chloride (5×, 20 ml total). The combined extract layers provide 8 mg of material. The 8 mg is then purified by chromatography (5 cm×0.5 cm disposable pipet, 40-63 μ silica) eluting with 1% and 2.5% methanol/methylene chloride gradient while collecting 0.4 ml fractions. The appropriate fractions are pooled and concentrated to provide the title compound.

Quelle