Ammonium Hydroxide → 4-chloro-1-cyclopentyl-1H-pyrazolo[3,4-b]quinoline

Reaction equation

[CH:1]1([N:6]2[C:10]([NH:11][C:12]3[C:13](=[CH:17][CH:18]=[CH:19][CH:20]=3)[C:14](O)=O)=[CH:9][CH:8]=[N:7]2)[CH2:5][CH2:4][CH2:3][CH2:2]1.[NH4+].[OH-].O=P(Cl)(Cl)[Cl:25]>>[Cl:25][C:14]1[C:13]2[C:12](=[CH:20][CH:19]=[CH:18][CH:17]=2)[N:11]=[C:10]2[N:6]([CH:1]3[CH2:5][CH2:4][CH2:3][CH2:2]3)[N:7]=[CH:8][C:9]=12

Participants

Reactant 3

HCID 14923Ammonium Hydroxide

HCID 24813Phosphorus oxychloride

HCID 54038843N-(1-cyclopentylpyrazol-5-yl) anthranilic acid

Product 1

HCID 212176854-chloro-1-cyclopentyl-1H-pyrazolo[3,4-b]quinoline

Procedure

A mixture of N-(1-cyclopentylpyrazol-5-yl) anthranilic acid (21 g, 0.0775 mol) and POCl3 (100 ml) is refluxed for 8 hours. The reaction mixture is poured into ice waterl and neutralized with NH4OH. A gum forms which is extracted with CH2Cl2. The CH2Cl2 layer is then washed with water, dried over MgSO4, filtered and concentrated. The residue is purified by column chromatography on silica gel eluting with 40% to 70% CH2Cl2 /hexane to afford 7.5 g of 4-chloro-1-cyclopentyl-1H-pyrazolo[3,4-b]quinoline, m.p. 97°-98° C.