Dichloromethane → 5-chloro-1-methyl-3-(pyridin-4-yl)-1H-indazole

HRID 879417Notes

Reaction equation

Br[C:2]1[C:10]2[C:5](=[CH:6][CH:7]=[C:8]([Cl:11])[CH:9]=2)[N:4]([CH3:12])[N:3]=1.[N:13]1[CH:18]=[CH:17][C:16](B(O)O)=[CH:15][CH:14]=1.C(Cl)Cl.[O-]P([O-])([O-])=O.[K+].[K+].[K+]>C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2]>[Cl:11][C:8]1[CH:9]=[C:10]2[C:5](=[CH:6][CH:7]=1)[N:4]([CH3:12])[N:3]=[C:2]2[C:16]1[CH:17]=[CH:18][N:13]=[CH:14][CH:15]=1

Participants

Conditions

Temperature: 90 °C

Procedure

To a pressure flask was added 3-bromo-5-chloro-1-methyl-1H-indazole (0.737 g, 3 mmol), pyridine-4-boronic acid (0.996 g, 8.1 mmol), PdCl2(dppf).DCM (0.490 g, 0.6 mmol), and K3PO4 (3.184 g, 15 mmol). The flask was flushed with argon for 5 minutes, then dry DME (15 mL) was added and the flask sealed under argon. The reaction was then heated to 90° C. for 4 hours. Additional PdCl2(dppf).DCM (0.245 g, 0.3 mmol) and pyridine-4-boronic acid (0.370 g, 3 mmol) were added, and heating was continued for another 14 h at 90° C. After cooling to room temperature, the crude reaction was filtered over a plug of Celite, concentrated, dissolved in DCM, and purified by column chromatography (gradient 0 to 75% EtOAc/hexanes) to afford the product. 1H NMR (400 MHz, CDCl3) δ 8.73 (d, J=6.0 Hz, 2H), 8.02 (d, J=0.6 Hz, 1H), 7.87 (d, J=6.1 Hz, 2H), 7.53-7.32 (m, 2H), 4.15 (s, 3H).

Workup

customThe flask was flushed with argon for 5 minutes
additiondry DME (15 mL) was added
customthe flask sealed under argon
temperatureheating
temperatureAfter cooling to room temperature
customthe crude reaction
filtrationwas filtered over a plug of Celite
concentrationconcentrated
dissolutiondissolved in DCM
custompurified by column chromatography (gradient 0 to 75% EtOAc/hexanes)
customto afford the product

Sources & evidence

ORD record: ord-b305a7d8b93a40fc98ac116379b255c0
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08987250B2

Reaction notes

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