Sulfuric Acid → 6-Fluoro-4-hydroxy-3-methyl-naphthalene-2-carboxylic acid methyl ester

HRID 1261426

Reaktionsgleichung

Reaktionsgleichung von HRID 1261426
[F:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[CH:8]=[C:7]([C:12]([OH:14])=[O:13])[C:6]([CH3:15])=[C:5]2[OH:16].S(=O)(=O)(O)O.[C:22](OCC)(=O)C.CCCCCC>CO>[CH3:22][O:13][C:12]([C:7]1[C:6]([CH3:15])=[C:5]([OH:16])[C:4]2[C:9](=[CH:10][CH:11]=[C:2]([F:1])[CH:3]=2)[CH:8]=1)=[O:14]

Komponenten

5

Versuchsvorschrift

To a 0° C. solution of 6-fluoro-4-hydroxy-3-methyl-naphthalene-2-carboxylic acid (28 g, 127 mmol) in MeOH (240 mL) was added concentrated sulfuric acid (18.9 mL, 382 mmol) dropwise. The reaction mixture was then warmed to room temperature and refluxed overnight. After this time, the methanol was distilled off under reduced pressure, and the crude mixture was diluted with ethyl acetate. This solution was washed with saturated aqueous NaHCO3. The organic phase was dried over Na2SO4, filtered and concentrated under reduced pressure to give the crude product. Silica gel column chromatography (6% ethyl acetate-hexane) afforded 6-fluoro-4-hydroxy-3-methyl-naphthalene-2-carboxylic acid methyl ester (14.8 g, 50%) as light yellow solid. MS cald. for C13H12FO3 [(M+H)+]: 235, obsd. 235.2.

Aufarbeitung

  1. temperaturerefluxed overnight
  2. distillationAfter this time, the methanol was distilled off under reduced pressure
  3. additionthe crude mixture was diluted with ethyl acetate
  4. washThis solution was washed with saturated aqueous NaHCO3
  5. dry with materialThe organic phase was dried over Na2SO4
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customto give the crude product

Quellen und Nachweise

ORD-Eintrag
ord-24b670ed1b4344b583cc1430a3e25928
Quelldatensatz
uspto-grants-2013_06
Patentnummer
US08470884B2

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