Quinone → HCID 67352452, compound

Temperature

75 °C

Using oven dried glassware and under an atmosphere of nitrogen, anhydrous zinc chloride (25 g, 183 mmol) was stirred in anhydrous methanol (60 mL) then heated to a 75° C. internal temperature. Methyl 4-fluorobenzoylacetate (39.6 g, 202 mmol) was added as a single portion followed by dropwise addition of a solution of p-benzoquinone (19.83 g, 183 mmol) in anhydrous diethyl ether (500 mL) over 4 hours. This was performed with a simultaneous distillation of ether from the reaction mixture such that the reaction volume remained approximately constant (a bath temperature of 140° C. maintained an internal temperature initially at 75° C. then gradually increasing to a maximum of 115° C.). 2.5 hours after the start of the benzoquinone addition, more methanol (20 mL) was added to facilitate stirring. After addition of benzoquinone was complete, heating of the reaction mixture at 100° C. (internal) continued for 1 hour. The reaction mixture was cooled to room temperature and partitioned between water (500 mL) and ethyl acetate (800 mL). The insoluble solids were removed from the biphasic solution by filtration and the organic layer was then separated, dried (Na2SO4), filtered and evaporated under vacuum. The brown residue was slurried in warm dichloromethane (˜225 mL) and the mixture was left to stand in a refrigerator for 18 hours. The resulting solids were filtered from the dark brown solution, washed with a small volume of dichloromethane then dried under vacuum to give Methyl 2-(4-fluorophenyl)-5-hydroxy-1-benzofuran-3-carboxylate. LCMS (m/z, ES+)=285 (M−1).

1. customdried glassware
2. distillationThis was performed with a simultaneous distillation of ether from the reaction mixture such that the reaction volume
3. customtemperature of 140° C.
4. temperaturemaintained an internal temperature initially at 75° C.
5. temperaturethen gradually increasing to a maximum of 115° C.)
6. addition2.5 hours after the start of the benzoquinone addition, more methanol (20 mL)
7. additionwas added
8. additionAfter addition of benzoquinone
9. temperatureheating of the reaction mixture at 100° C. (internal)
10. temperatureThe reaction mixture was cooled to room temperature
11. custompartitioned between water (500 mL) and ethyl acetate (800 mL)
12. customThe insoluble solids were removed from the biphasic solution by filtration
13. customthe organic layer was then separated
14. dry with materialdried (Na2SO4)
15. filtrationfiltered
16. customevaporated under vacuum
17. waitthe mixture was left
18. waitto stand in a refrigerator for 18 hours
19. filtrationThe resulting solids were filtered from the dark brown solution
20. washwashed with a small volume of dichloromethane
21. customthen dried under vacuum

ORD record

ord-3f67355a229f4a6f93ba0349397e5570

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09119868B2