Reaktion #76285

Reaktionsgleichung

4-bromo-2-chlorobenzoic acid

4-Bromo-2-chlorobenzoic Acid

3,5-dimethoxyphenol

potassium carbonate

hydrochloric acid

→

desired compound ( 20 )

Ausbeute 62.6%

2-Bromo-7,9-dihydroxy-10,11-dihydrodibenz[b,f]oxepin-10-one

Ausbeute 62.6%

Lösungsmittel

ethyl acetate

N-methyl-2-pyrrolidone

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Trocknenthe resulting solution was dried by a Dean-Stark water separator (140-170° C.) for three hours
2. 2
   TemperaturThis reaction mixture was cooled
3. 3
   Filtrationfiltered
4. 4
   SonstigeThe organic layer was separated
5. 5
   Waschenthoroughly washed with water
6. 6
   TrocknenThe resulting solution was dried with anhydrous magnesium sulfate
7. 7
   Einengenconcentrated
8. 8
   Sonstigethe residue was purified by silica gel column chromatography (developing solvent; ethyl acetate:hexane=1:3)
9. 9
   Sonstigerecrystallized from ethyl acetate-hexane

Vorschrift

To a mixture of 88.3 g (F.W. 235.46, 375 mmol) of 4-bromo-2-chlorobenzoic acid (3), 57.8 g (F.W. 154.165, 375 mmol) of 3,5-dimethoxyphenol (13), 93.2 g (F.W. 138.21, 670 mmol) of potassium carbonate and 400 mL of N-methyl-2-pyrrolidone was added benzene (200 mL), and the resulting solution was dried by a Dean-Stark water separator (140-170° C.) for three hours and then, 6.0 g (F.W. 63.55, 93.7 mmol) of copper (powder) and 17.8 g (F.W. 190.45, 93.7 mmol) of copper (I) iodide were added thereto and stirred at 120° C. for 30 minutes. This reaction mixture was cooled by standing and ice water and ethyl acetate were added thereto and then, the obtained solution was made pH 2 with concentrated hydrochloric acid and filtered. The organic layer was separated and then, thoroughly washed with water and subjected to salting out with a saturated sodium chloride aqueous solution. The resulting solution was dried with anhydrous magnesium sulfate and concentrated and the residue was purified by silica gel column chromatography (developing solvent; ethyl acetate:hexane=1:3) and recrystallized from ethyl acetate-hexane to obtain 75.4 g (57%) a desired compound (20). (TLC; ethyl acetate:hexane=1:2 or 1:1).

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