Reaktion #1156421

Reaktionsgleichung

acetic acid 4-(9-bromo-2,3-dimethyl-naphtho[2,3-b]thiophen-4-yl)-2,6-dimethyl-phenyl ester

potassium hydroxide

→

title compound

Ausbeute 93.5%

4-(9-Bromo-2,3-dimethyl-naphtho[2,3-b]thiophen-4-yl)-2,6-dimethyl-phenol

Ausbeute 93.5%

Lösungsmittel

tetrahydrofuran

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe reaction was removed from the freezer
2. 2
   workup.ADDITIONMore aqueous potassium hydroxide (41.5 mL of a 1N solution, 41.5 mmol), tetrahydrofuran (50 mL), and methanol (10 mL) were added
3. 3
   workup.ADDITIONThe mixture was diluted with water (500 mL)
4. 4
   Extraktionextracted with diethyl ether
5. 5
   WaschenThe diethyl ether layer was washed twice with water (500 mL)
6. 6
   Trocknendried (MgSO4)
7. 7
   EinengenConcentration under reduced pressure
8. 8
   Sonstigegave a residue which

Vorschrift

To a solution of acetic acid 4-(9-bromo-2,3-dimethyl-naphtho[2,3-b]thiophen-4-yl)-2,6-dimethyl-phenyl ester (6.5 g, 14.3 mmol) in tetrahydrofuran (240 mL) and methanol (80 mL) at room temperature was added dropwise aqueous potassium hydroxide (17.2 mL of a 1N solution, 17.2 mmol). After 4 h at room temperature the reaction mixture was placed in the freezer for 18 h. The reaction was removed from the freezer and allowed to stir at room temperature. More aqueous potassium hydroxide (41.5 mL of a 1N solution, 41.5 mmol), tetrahydrofuran (50 mL), and methanol (10 mL) were added. The mixture was diluted with water (500 mL), acidified with 1N aqueous solution of hydrochloric acid, and extracted with diethyl ether. The diethyl ether layer was washed twice with water (500 mL), and dried (MgSO4). Concentration under reduced pressure gave a residue which was adsorbed onto silica gel. Chromatography with petroleum ether:ethyl acetate (97:3, then 95:5) gave the title compound as a white foamy solid (5.5 g, 93%): NMR (CDCl3): δ8.41 (s, 1H), 8.16 (d, 1H), 7.64-7.54 (m, 2H), 7.46-7.40 (m, 1H), 6.89 (s, 2H), 2.41 (s, 3H), 2.23 (s, 6H), 1.60 (s, 3H); MS(−ESI): [M−H], 1 bromine isotope pattern, 409/411.

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