Cesium carbonate → 2-[4-(4-hydroxy-indol-1-yl)-6-oxo-6H-pyridazin-1-yl]-4-methyl-pentanoic acid [1-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-1H-pyrazol-3-yl]-amide

Participants

Reaction Conditions

Reaction Steps

A solution of 2-[4-(benzotriazol-1-yloxy)-6-oxo-6H-pyridazin-1-yl]-4-methyl-pentanoic acid [1-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-1H-pyrazol-3-yl]-amide (Example 109, Step 1, 0.50 g, 0.95 mmol) in N,N-dimethylformamide (4 mL, 0.24M) was treated with cesium carbonate (0.62 g, 1.90 mmol) and 1H-indol-4-ol (0.15 g, 1.13 mmol). The resulting reaction mixture was stirred at 80° C. overnight. The reaction mixture was then concentrated in vacuo, diluted with water (100 mL), and acidified with a 1N aqueous hydrochloric acid solution. Ethyl acetate (75 mL) was added, and the mixture was filtered through filter paper, rinsing with water and ethyl acetate. The layers were separated, and the aqueous layer was back extracted with ethyl acetate (75 mL). The combined organics were washed with a saturated aqueous sodium chloride solution (100 mL), dried over magnesium sulfate, filtered, rinsed, and concentrated in vacuo. Silica gel column chromatography (AnaLogix 40 g, 1-10% methanol/methylene chloride) followed by chromatography (Pursuit C-18 column 5×25 cm, 0.05% trifluoroacetic acid/water/acetonitrile linear gradient, 50 ml/min, 45 min run) afforded impure 2-[4-(4-hydroxy-indol-1-yl)-6-oxo-6H-pyridazin-1-yl]-4-methyl-pentanoic acid [1-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-1H-pyrazol-3-yl]-amide (66 mg).

Provenance & Evidence