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

HRID 1733831

Reaction equation

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

Participants

Conditions

Temperature: -5 °C

Procedure

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.

Workup

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

Sources & evidence

ORD record: ord-d2c683369da8493e81652986b6d426f7
Source dataset: uspto-grants-1996_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05532207

Linked notes

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