Diethyl Sulfate → HCID 69269049, compound

Participants

Reaction Steps

Into a 100 mL 3 neck round bottom flask equipped with a reflux condenser, nitrogen inlet and magnetic stirrer is added 700 mg (2.24 mg, 1.0 equiv.) of 8-Bromo-6-hydroxy-4-oxo-4H-chromene-2-carboxylic acid ethyl ester (Reference Example 23a). This material is dissolved in 50 mL of toluene, then 689 mg, 586 μL (4.47 mmol, 2.0 equiv.) of diethyl sulfate and 309 mg (2.24 mmol, 1.0 equiv.) of K2CO3 were added. The reaction was then heated to reflux for 24 hr. At the end of this time, monitoring by LC/MS reveals that the reaction is>than 95% complete. The reaction is then cooled, 100 mL of ethyl acetate is added and the organic layer is washed with 0.5N HCl solution, dried over Na2SO4, filtered and concentrated. The residues were subjected to flash chromatography, using 40% ethyl acetate in hexane as eluent. The purified fractions were concentrated to yield 500 mg (65%) of a colorless solid.

Provenance & Evidence