Reaktion #54818

Reaktionsgleichung

potassium carbonate

1-(2-naphthoylmethyl)imidazole hydrochloride

ethylene glycol

p-toluenesulfonic acid monohydrate

→

1-[2,2-ethylenedioxy-2-(2-naphthyl)ethyl]imidazole

Lösungsmittel

toluene

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONA mixture of 5.45 g
2. 2
   Temperaturunder reflux through a Dean-Stark trap
3. 3
   SonstigeThe trap is then replaced by a separatory funnel
4. 4
   workup.ADDITIONcontaining 4 A molecular seives
5. 5
   Temperaturheating
6. 6
   workup.WAITis continued for a further day
7. 7
   TemperaturAfter cooling
8. 8
   workup.ADDITIONthe mixture is treated with 200 ml
9. 9
   Sonstigethe organic phase separated
10. 10
    Trocknendried (MgSO4)

Vorschrift

A mixture of 5.45 g. of 1-(2-naphthoylmethyl)imidazole hydrochloride, 2.49 g. ethylene glycol and 7.6 g. p-toluenesulfonic acid monohydrate in 50 ml. of toluene is heated overnight under reflux through a Dean-Stark trap. The trap is then replaced by a separatory funnel containing 4 A molecular seives and heating is continued for a further day. After cooling, the mixture is treated with 200 ml. of ethyl acetate, neutralized by pouring into excess aqueous potassium carbonate and the organic phase separated and dried (MgSO4) to afford a solution of 1-[2,2-ethylenedioxy-2-(2-naphthyl)ethyl]imidazole. The hydrochloride salt is prepared by dropwise addition of ethereal hydrogen chloride until precipitation is complete. Filtration and recrystallization from acetone/methanol gives 3.9 g. pure hydrochloride. m.p. 269°-270° C.

Quelle