Reaktion #4535

Reaktionsgleichung

acetic acid

potassium acetate

3-chloromethyl-5-dichloromethyl-2-phthalimidopyrazine

dichloromethane

→

3-acetoxymethyl-5-dichloromethyl-2-phthalimidopyrazine

Ausbeute 77.0%

Lösungsmittel

dimethyl sulfoxide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONthe resulting mixture was mixed thoroughly
2. 2
   Sonstigephase separation
3. 3
   ExtraktionThe aqueous phase was extracted once with 500 ml of dichloromethane and once with 250 ml of dichloromethane
4. 4
   WaschenThe combined organic phases were washed twice with 1,000 ml of water
5. 5
   Trocknendried over sodium sulfate
6. 6
   Sonstigeevaporated down in a rotary evaporator
7. 7
   workup.WAITthe solution was left
8. 8
   Sonstigeto crystallize at room temperature
9. 9
   Filtrationfiltered off
10. 10
    Sonstigedried
11. 11
    SonstigeThe crystals were then recrystallized again from methanol

Vorschrift

50 ml of absolute glacial acetic acid and 35 g of potassium acetate were added to a solution of 57.7 g (0.16 mole) of 65% strength 3-chloromethyl-5-dichloromethyl-2-phthalimidopyrazine in 1,000 ml of dimethyl sulfoxide, and the mixture was then stirred for three days at room temperature. Thereafter, 1,000 ml of dichloromethane and 1,000 ml of ice-water were added to the reaction mixture, the resulting mixture was mixed thoroughly, and phase separation was effected. The aqueous phase was extracted once with 500 ml of dichloromethane and once with 250 ml of dichloromethane. The combined organic phases were washed twice with 1,000 ml of water, dried over sodium sulfate and evaporated down in a rotary evaporator. The blackish brown oil was taken up in 20 ml of methanol at the boil, and the solution was left to crystallize at room temperature. The product was then suspended in a little diethyl ether, filtered off and dried. The crystals were then recrystallized again from methanol. 30.6 g (77% of theory) of 3-acetoxymethyl-5-dichloromethyl-2-phthalimidopyrazine of melting point 117°-118° C. were obtained. 1H-NMR (270 MHz, CDCl3): δ1.9 (s, 3H), 5.3 (s, 2H), 6.9 (s, 1H), 8.1 (m, 4H), 9.1 (s, 1H).

Quelle