Tetrahydrofuran → (S)-3-bromo-7-(pyrimidin-5-yl)-5'H-spiro[chromeno[2,3-b]pyridine-5,4'-oxazol]-2'-amine

Participants

Reaction Conditions

Reaction Steps

A sealable tube was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (2.000 g, 4.37 mmol), pd(ph3p)4 (0.504 g, 0.437 mmol), pyrimidin-5-ylboronic acid (0.568 g, 4.58 mmol) and THF (21.83 mL, 4.37 mmol). The mixture was flushed with Ar then a solution of potassium carbonate (1.5 M) (5.82 mL, 8.73 mmol) was added. The reaction was heated at 110° C. for 2 hours before being diluted with water 50 mL and poured into a separatory funnel containing EtOAc 50 mL. The layers were separated and the aqueous layer was extracted with EtOAc 3×100 mL. The aqeuous layer was then extracted with DCM (3×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (80 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow foam. Step 2: Combined (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (75 mg, 0.183 mmol), tetrakis(triphenylphosphine)palladium (21.13 mg, 0.018 mmol), copper iodide (3.48 mg, 0.018 mmol), THF (366 μL, 0.183 mmol) and DMF (366 μL, 0.183 mmol) in a reaction vial. To the mixture was added diisopropyl amine (512 μL, 3.66 mmol) then ethynylcyclopropane (60.4 mg, 0.914 mmol). The reaction vial was sealed and heated at 110° C. for 1.5 hours. The reaction was allowed to cool to RT before being diluted with water (15 mL) and poured into a separatory funnel containing ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (1×25 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (12 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an orange solid.

Provenance & Evidence