반응 #82452

반응 방정식

Vilsmeier reagent

Phosphorous oxychloride

Dimethylformamide

dimethyl [(1-methylpyrazol-4-yl)amino]butenedicarboxylate

→

product

수율 71.4%

Dimethyl 1-methylpyrazolo[4,3-b]pyridine-5,6-dicarboxylate

수율 71.4%

용매

dichloroethane

dichloroethane

반응 조건

후처리

1. 1
   온도to warm slowly to room temperature
2. 2
   기타the reaction temperature below 5° C
3. 3
   온도to warm slowly to room temperature over four hours
4. 4
   온도is heated
5. 5
   온도to reflux for one hour
6. 6
   농축The mixture is concentrated to a solid which
7. 7
   기타is chromatographed
8. 8
   workup.ADDITIONThe fractions containing the desired product
9. 9
   농축concentrated

실험 절차

Dimethylformamide (7.4 mL, 0.096 mol) is dissolved in 125 mL dichloroethane and the mixture cooled to -5° C. in an acetone/ice bath. Phosphorous oxychloride (8.9 mL, 0.095 mol) is added in one portion and the clear colorless solution is allowed to warm slowly to room temperature, gradually turning yellow. The unpurified dimethyl [(1-methylpyrazol-4-yl)amino]butenedicarboxylate is dissolved in 75 mL of dichloroethane and added to the chilled Vilsmeier reagent dropwise keeping the reaction temperature below 5° C. The mixture is allowed to warm slowly to room temperature over four hours, and then is heated to reflux for one hour. The mixture is concentrated to a solid which is chromatographed using 3:1 hexanes/ethyl acetate. The fractions containing the desired product are combined and concentrated to give the product as a white solid (16.93 g, 71.4%), melting point 148°-149° C.

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