Phosphorus oxychloride → 4-chloro-1,3-dimethyl-6-phenyl-1H-pyrazolo[3,4-b]pyridine
Reaktionsgleichung
[CH3:1][N:2]1[C:6]2=[N:7][C:8]([C:12]3[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=3)=[CH:9][C:10](O)=[C:5]2[C:4]([CH3:18])=[N:3]1.P(Cl)(Cl)([Cl:21])=O>>[Cl:21][C:10]1[CH:9]=[C:8]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[N:7]=[C:6]2[N:2]([CH3:1])[N:3]=[C:4]([CH3:18])[C:5]=12Komponenten
3
Versuchsvorschrift
73 gms. of 1,3-dimethyl-4-hydroxy-6-phenyl-1H-pyrazolo[3,4-b]pyridine (0.31 mol.) are refluxed in 800 ml. of phosphorus oxychloride for 6 hours. The excess phosphorus oxychloride is removed in vacuo and the oily residue is treated with ice-water by which operation the compound becomes solid. The compound is extracted with ether, washed with an aqueous sodium carbonate solution (10%) and again with water. Evaporation of the dried (Na2SO4) and charcoal treated ethereal extract provides 4-chloro-1,3 -dimethyl-6-phenyl-1H-pyrazolo[3,4-b]-pyridine which is washed with absolute ethanol, yield: 55.6 gms. (69.8%) of white product melting at 89°-90° C.
Aufarbeitung
- customThe excess phosphorus oxychloride is removed in vacuo