Chloropyrazine → 4-pyrazin-2-yl-1H-indole

HRID 1159807Notes

Reaction equation

Br[C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[CH:5][NH:6]2.B1(B2OC(C)(C)C(C)(C)O2)OC(C)(C)C(C)(C)O1.C([O-])(=O)C.[K+].C([O-])(O)=O.[Na+].Cl[C:40]1[CH:45]=[N:44][CH:43]=[CH:42][N:41]=1>COCCOC.ClCCl.Cl[Pd]Cl.O>[N:41]1[CH:42]=[CH:43][N:44]=[CH:45][C:40]=1[C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[CH:5][NH:6]2

Participants

Conditions

Temperature: 125 °C

Procedure

4-Bromoindole (0.1 g, 0.51 mmol), bis(pinacolato)diboron (0.172 g, 0.77 mmol), potassium acetate (0.075 g, 0.765 mmol) and PdCl2 (0.022 g, 0.031 mmol) were dissolved in DME (3 mL) and heated in the microwave for 900 seconds at 125° C. The reaction was cooled and NaHCO3 (0.129 g, 1.53 mmol), 2-chloropyrazine (0.087 g, 0.77 mmol) tetrakis(triphenylphosphine)palladium (0.0295 g, 0.026 mmol), H2O (1 mL) and DME (1 mL) were added and the mixture was stirred in the microwave for 900 seconds at 120° C. The mixture was diluted with dichloromethane and filtered. The filtrate was washed with water (2×), dried (MgSO4) and evaporated. The crude product was purified by flash chromatography using 2.5% to 5% CH3OH in dichloromethane. Not pure, purified by flash chromatography using hexane/EtOAc 7:3 to 1:1 as the eluent. Yield: 93 mg (47%). White solid. MS (electronspray; [M+H]+) m/z 196.3.

Workup

temperatureThe reaction was cooled
filtrationfiltered
washThe filtrate was washed with water (2×)
dry with materialdried (MgSO4)
customevaporated
customThe crude product was purified by flash chromatography
customNot pure, purified by flash chromatography

Sources & evidence

ORD record: ord-fe6fd4cded794428afabcbe8cad33f60
Source dataset: uspto-grants-2010_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07812017B2

Reaction notes

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