Phosphorus oxychloride → 7-Chloro-3-(4-chlorophenyl)-2-(2,4-dichlorophenyl)-2H-pyrazolo[3,4-c]pyridine
Reaction equation
C([N:8]1[CH:13]=[CH:12][C:11]2=[C:14]([C:25]3[CH:30]=[CH:29][C:28]([Cl:31])=[CH:27][CH:26]=3)[N:15]([C:17]3[CH:22]=[CH:21][C:20]([Cl:23])=[CH:19][C:18]=3[Cl:24])[N:16]=[C:10]2[C:9]1=O)C1C=CC=CC=1.O=P(Cl)(Cl)[Cl:35]>>[Cl:35][C:9]1[C:10]2=[N:16][N:15]([C:17]3[CH:22]=[CH:21][C:20]([Cl:23])=[CH:19][C:18]=3[Cl:24])[C:14]([C:25]3[CH:30]=[CH:29][C:28]([Cl:31])=[CH:27][CH:26]=3)=[C:11]2[CH:12]=[CH:13][N:8]=1Participants
3
Procedure
A stirred suspension of 6-benzyl-3-(4-chlorophenyl)-2-(2,4-dichlorophenyl)-2,6-dihydropyrazolo[3,4-c]pyridin-7-one (I-1A-1b; 153 mg, 0.32 mmol) in POCl3 (3.5 ml) was heated to reflux for 48 hr. After the reaction was cooled and concentrated, in vacuo, an ethyl acetate solution of the residue was washed with saturated aqueous NaHCO3 and then brine. The solution was dried (Na2SO4), concentrated, in vacuo, and then purified on a Biotage™ Flash 12M column using 0-15-30% ethyl acetate in hexanes to afford I-1A-1c as an off-white solid (75 mg, 58%): +ESI MS (M+1) 408.0; 1H NMR (400 MHz, CD2Cl2) δ 8.01 (d, J=5.8 Hz, 1H), 7.57-7.53 (m, 3H), 7.47 (dd, J=8.7, 2.1 Hz, 1H), 7.41 (d, J=8.7 Hz, 2H), 7.27 (d, J=8.7 Hz, 2H).