Dimethylformamide → 1h-Pyrazolo[4,3-b]pyridine-5,6-dicarboxylic acid,1-methyl-,5,6-dimethyl ester

HRID 54174

Reaktionsgleichung

CN(C)[CH:3]=[O:4].P(Cl)(Cl)(Cl)=[O:7].[CH3:11][N:12]1[CH:16]=[C:15]([NH:17][C:18]([CH2:28]C)=[C:19]([C:24](OC)=O)[C:20]([O:22][CH3:23])=[O:21])[CH:14]=[N:13]1.C[N+](C)=CCl.[Cl-]>ClC(Cl)C>[CH3:11][N:12]1[C:16]2[C:15](=[N:17][C:18]([C:28]([O:4][CH3:3])=[O:7])=[C:19]([C:20]([O:22][CH3:23])=[O:21])[CH:24]=2)[CH:14]=[N:13]1

Komponenten

Reaktionsbedingungen

Temperatur: -5 °C

Versuchsvorschrift

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.

Aufarbeitung

temperatureto warm slowly to room temperature
customthe reaction temperature below 5° C
temperatureto warm slowly to room temperature over four hours
temperatureis heated
temperatureto reflux for one hour
concentrationThe mixture is concentrated to a solid which
customis chromatographed
additionThe fractions containing the desired product
concentrationconcentrated

Quellen und Nachweise

ORD-Eintrag: ord-a77062d5646d4f869936606dd576b9d1
Quelldatensatz: uspto-grants-1997_04
DOI: 10.6084/m9.figshare.5104873.v1
Patentnummer: US05622913

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