Diethyl Ether → HCID 12043677, compound

Participants

Reaction Steps

A 2.0 M solution of isopropyl magnesium chloride in diethyl ether (15.5 mL, 31 mmol) was added slowly to a solution of 7-bromo-2,2-dimethyl-chroman-4-one (Compound 65, 1.58 g, 6.2 mmol) and 1,3-dimethyl-3,4,5,6-tetrahydro 2(1H) pyrimidone (DMPU) (7.5 mL, 30 mmol) in 30 mL THF at −30° C. The reaction mixture was warmed to room temperature and stirred for 15 hours. The reaction was then quenched with water (20 mL), saturated NH4Cl (aq) (15 mL) and 10% HCl (20 mL) at −78° C. The mixture was warmed to room temperature, was extracted with ethyl acetate (3×30 mL), the combined extracts were washed with water and brine, dried (MgSO4), filtered, and concentrated in vacuo. The residue was then refluxed in 40 mL methanol with p-toluenesulfonic acid (160 mg) for 20 hours. The reaction mixture was made basic by addition of solid K2CO3, the solvent was removed and the residue was dissolved in diethyl ether (50 mL). The ether solution was washed with water (2×50 mL) and brine (50 mL), dried (MgSO4), filtered, and concentrated in vacuo. The resulting crude product was purified by column chromatography on silica gel (hexane) to give the title compound as a clear oil: (650 mg, 37%).

Provenance & Evidence