Reaktion #836612

Reaktionsgleichung

Sodium ethoxide

N-[2-cyano-3-(dimethylamino)prop-2-en-1-ylidene]-N-methylmethanaminium perchlorate

ethyl 2-thienylacetate

quinoline

→

ethyl 5-cyano-1-benzothiophene-7-carboxylate

Ausbeute 43.0%

Lösungsmittel

Hydrochloric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITat room temperature for 15 min
2. 2
   TemperaturThe reaction mixture was heated to 75° C. under nitrogen for 5 h
3. 3
   Temperaturcooled to 0° C
4. 4
   Extraktionthe mixture extracted thrice with chloroform
5. 5
   WaschenThe organic solution was washed with brine
6. 6
   Trocknendried over Na2SO4
7. 7
   SonstigeThe solvent was removed by evaporation
8. 8
   Sonstigethe residue flash chromatographed on silica gel (hexane-ethyl acetate, 8:1)

Vorschrift

N-[2-cyano-3-(dimethylamino)prop-2-en-1-ylidene]-N-methylmethanaminium perchlorate (see Collect. Czech. Chem. Commun.; 32; 5; 1967; 1704; 5.84 g, 23.2 mmol) and ethyl 2-thienylacetate (3.95 g, 23.2 mmol) were mixed with quinoline (117 mL) at 0° C. Sodium ethoxide (1.97 g, 27.9 mmol) was added and the mixture was stirred at 0° C. for 30 min and then at room temperature for 15 min. The reaction mixture was heated to 75° C. under nitrogen for 5 h and then cooled to 0° C. Hydrochloric acid (200 mL of 2 M aqueous solution) was added and the mixture extracted thrice with chloroform. The organic solution was washed with brine and then dried over Na2SO4. The solvent was removed by evaporation and the residue flash chromatographed on silica gel (hexane-ethyl acetate, 8:1). There was obtained 2.3 g (43%) of ethyl 5-cyano-1-benzothiophene-7-carboxylate as a pale yellow solid. 1H NMR (300 MHz, CDCl3): 1.5 (t, 3H), 4.5 (qt, 2H), 7.5 (d, 1H), 7.7 (d, 1H), 8.3 (m, 2H).

Quelle