Sodium Carbonate → 6-(1H-indol-4-yl)-1H-indazol-4-amine

Participants

Reaction Conditions

Reaction Steps

6-Bromo-1H-indazol-4-amine (available from Sinova, 10.0 g, 47.2 mmol) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (available from Frontier Scientific, Europe Ltd, 16.05 g, 66.0 mmol) were dissolved in 1,4-dioxane (60 ml) and water (60 ml). Sodium carbonate solution (2 M, 70.7 ml) and Pd(dppf)Cl2-DCM adduct (1.926 g, 2.36 mmol) were added and the mixture was heated at 115° C. for 18 hr. The reaction mixture was diluted with dichloromethane (200 ml) and the organic and aqueous layers were separated by hydrophobic frit. The aqueous layer was extracted with further quantities of dichloromethane (2×200 ml), using a hydrophobic frit to separate the layers. The organic layers were combined and silica (80 g) was added. The solvent was removed in vacuo to give a crude material which was purified by chromatography on silica gel (750 g cartridge, Flashmaster II) eluting with 0-100% ethyl acetate in cyclohexane over 60 minutes. The oil was dried in vacuo on a drying rack overnight. The yellow foam was dissolved in dichloromethane (3×400 ml), removing the solvent in vacuo after each dissolution. ethyl acetate (50 ml) was then added and the solvent was removed in vacuo. The solid obtained was dried in a vacuum oven to give the title compound (12.8 g) as a yellow foam.

Provenance & Evidence