Reaktion #2354476

Reaktionsgleichung

benzo[b]thiophen-5-amine

hexane-2,5-dione

acetic acid

→

1-(benzo[b]thiophen-5-yl)-2,5-dimethyl-1H-pyrrole

Ausbeute 97.0%

Lösungsmittel

benzene

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto reflux under a Dean-Stark head
2. 2
   Waschensuccessively washed with aqueous 2 N hydrochloric acid (30 mL), brine (30 mL)
3. 3
   SonstigeThe organic layer was separated
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Sonstigethe solvent evaporated in vacuo

Vorschrift

A stirred solution of benzo[b]thiophen-5-amine (2.48 g, 17.0 mmol), hexane-2,5-dione (1.95 mL, 17.0 mmol) and glacial acetic acid (0.2 mL) in benzene (35 mL) was heated to reflux under a Dean-Stark head. After 14 h the reaction was cooled to r.t., diluted with diethyl ether (40 mL), and successively washed with aqueous 2 N hydrochloric acid (30 mL), brine (30 mL), a saturated aqueous solution of sodium hydrogen carbonate (30 mL) and finally brine (30 mL). The organic layer was separated, dried over magnesium sulfate, filtered and the solvent evaporated in vacuo to yield 1-(benzo[b]thiophen-5-yl)-2,5-dimethyl-1H-pyrrole (3.67 g, 97%) as a light orange crystalline solid. 1H NMR δ (CDCl3, 400 MHz) 2.04 (s, 6 H), 5.93 (s, 2 H), 7.19 (dd, J=8, 2 Hz, 1 H), 7.37 (d, J=5 Hz, 1 H), 7.55 (d, J=5 Hz, 1 H), 7.66 (d, J=2 Hz, 1 H), 7.94 (d, J=9 Hz, 1 H).

Quelle