Acetic Anhydride → HCID 15740989, Verbindung

To an ice cold solution of 2,5-dibromo-3-nitrothiophene (5.0 g, 17.4 mmol, DellErba, C.; Spinelli, D. Tetrahedron, 1965, 21, 1061-1066) in acetic acid-acetic anhydride (1:1, 50 mL) was added iron powder (5.8 g, 104.5 mmol) slowly for 15 min. and stirred at rt for 4 h. After completion of the reaction, the reaction mixture was poured into ice cold water (500 mL) and stirred for 15 min. The precipitated solid was filtered, washed with water and dried. The crude product was chromatographed over silica gel column using hexane-EtOAc (95:5) as eluent to give the product as a white color solid (3.0 g, 58%), mp 114-116° C. 1H NMR (400 MHz, CDCl3): δ 7.78 (1H, s), 7.21 (1H, s), 2.20 (3H, s).