Reaktion #69652

Reaktionsgleichung

carbon dioxide

n-Butyl lithium

4-ethylanisole

N,N,N′,N′-tetramethylethylenediamine

sodium hydroxide

→

5-ethyl-2-methoxybenzoic acid

Ausbeute 37.0%

Lösungsmittel

diethyl ether

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was cooled
2. 2
   Sonstigethe aqueous layer was separated
3. 3
   workup.ADDITIONacidified to pH 2 or below by the addition of concentrated hydrochloric acid
4. 4
   ExtraktionThe mixture was extracted with diethyl ether
5. 5
   Sonstigethe organic layer separated
6. 6
   Sonstigethe solvent removed in vacuo

Vorschrift

n-Butyl lithium (2.5M in hexanes, 38.5 ml, 100.0 mmol) was added dropwise under a nitrogen atmosphere to a stirred solution of 4-ethylanisole (11.7 g, 86.0 mmol) and N,N,N′,N′-tetramethylethylenediamine (10 ml, 88.0 mmol) in anhydrous diethyl ether (100 ml) and the mixture was stirred and held at 30° C. for 16 hours. The mixture was cooled and poured slowly in to a mixture of excess solid carbon dioxide in anhydrous diethyl ether. Upon warming to room temperature the mixture was made basic by the addition of 2M sodium hydroxide, the aqueous layer was separated and acidified to pH 2 or below by the addition of concentrated hydrochloric acid. The mixture was extracted with diethyl ether, the organic layer separated and the solvent removed in vacuo to afford 5-ethyl-2-methoxybenzoic acid (5.7 g, 37%) as a pale yellow oil. 1H NMR (DMSO-d6) 12.50 (1H, br s), 7.48 (1H, d), 7.33 (1H, dd), 7.03 (1H, d), 2.56 (2H, q), 1.17 (3H, q). MS: [M+H]+ 181.

Quelle