Reaktion #2374034

Reaktionsgleichung

3,4-Dihydro-2-trichloromethyl-2H-benzo[e]-[1,3]-oxazin-4-one

acetic anhydride

→

3-acetyl-3,4-dihydro-2-trichloromethyl-2H-benzo[e]-[1,3]-oxazin-4-one

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe oil which separated
2. 2
   Extraktionwas extracted into diethyl ether
3. 3
   SonstigeThe extract was dried
4. 4
   Sonstigethe solvent was evaporated
5. 5
   Sonstigeto leave an oil, which
6. 6
   Sonstigewas purified by column chromatography on "Kieselgel 60" (trade mark) silica
7. 7
   Waschenthe column was eluted with 10% v/v ethyl acetate in toluene
8. 8
   Sonstigefractions were collected
9. 9
   Sonstigethe solvent was evaporated

Vorschrift

3,4-Dihydro-2-trichloromethyl-2H-benzo[e]-[1,3]-oxazin-4-one (prepared as described in Example 3--4.0 g.) was stirred with acetic anhydride (40 ml.) on a steam-bath for 10 hours. The reaction mixture was cooled to room temperature, poured into water (400 ml.) and stirred for 3 hours, and the oil which separated was extracted into diethyl ether. The extract was dried and the solvent was evaporated to leave an oil, which was purified by column chromatography on "Kieselgel 60" (trade mark) silica, and the column was eluted with 10% v/v ethyl acetate in toluene. 25 Ml. fractions were collected, fractions 1-7 were combined, and the solvent was evaporated to give 3-acetyl-3,4-dihydro-2-trichloromethyl-2H-benzo[e]-[1,3]-oxazin-4-one as an oil. The n.m.r. spectrum in hexadeuterio-dimethylsulphoxide showed the following characteristic peaks (δ values):

Quelle