Hydrochloric Acid → 7-methoxychroman-3-one

Temperature

60 °C

7-Methoxy-2H-chromene-3-carboxylic acid (6.07 g, 29.44 mmol) and triethylamine (4.8 ml, 34.48 mmol) were dissolved in dichloromethane (60 ml). Diphenylphosphoryl azide (6.54 ml, 29.44 mmol) was dissolved in toluene (24 ml) and added dropwise to the reaction mixture while slowly increasing the temperature to 60° C. 60 ml of toluene were added and the reaction mixture was stirred at 70° C. for 90 minutes. A 10 molar HCl solution (28 ml) was then added and the reaction mixture was stirred at reflux for 2 hours. After cooling to room temperature the phases were separated. The organic phase was extracted with an aq. NaHCO3 solution. The organic layer was dried over magnesium sulfate, filtered, and the solvent evaporated under reduced pressure. The crude product was purified by chromatography using silica gel with cyclohexane/ethyl acetate (100:0 to 95:5) as eluent, yielding the title product (1.47 g, 24% yield).

1. additionadded dropwise to the reaction mixture
2. stirringthe reaction mixture was stirred
3. temperatureat reflux for 2 hours
4. temperatureAfter cooling to room temperature the phases
5. customwere separated
6. extractionThe organic phase was extracted with an aq. NaHCO3 solution
7. dry with materialThe organic layer was dried over magnesium sulfate
8. filtrationfiltered
9. customthe solvent evaporated under reduced pressure
10. customThe crude product was purified by chromatography

ORD record

ord-e7e7fedd02c546f09235e2228d528127

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08969552B2