Sodium Hydroxide → 3-(2-Chloropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine
Reaction equation
O=[C:2]1[CH:7]=[C:6]([C:8]2[C:9]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)=[N:10][N:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=23)[CH:5]=[CH:4][NH:3]1.P(Cl)(Cl)([Cl:25])=O.[OH-].[Na+]>>[Cl:25][C:2]1[CH:7]=[C:6]([C:8]2[C:9]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)=[N:10][N:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=23)[CH:5]=[CH:4][N:3]=1Participants
4
Conditions
- Temperature
- 70 °C
Procedure
A mixture of 3-(2-oxo-1,2-dihydropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (0.6 g) and phosphorus oxychloride (1.8 ml) was stirred for 6 hours at 70° C. After cooling, the reaction mixture was poured onto ice (30 g) and made alkaline with 24% aqueous solution of sodium hydroxide (pH=10) and extracted with chloroform (18 ml). The combined extract was washed with water and sodium chloride aqueous solution and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was chromatographed on silica gel (12 g) with chloroform as an eluent. The fractions containing the object compound were combined and evaporated in vacuo and recrystallized from a mixture of ethyl acetate and diisopropyl ether to give 3-(2-chloropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (0.21 g).