2-Thiophenecarboxaldehyde → HCID 86756151, compound

Participants

Reaction Steps

Thiophene-2-carboxaldehyde (5.66 g, 0.050 mol) was dissolved in an excess of acetic acid anhydride (10 ml) and 3 drops conc. sulfuric acid added under stirring. The resulting green mixture was allowed to react at room temperature for 2.5 hr. The reaction mixture was then diluted with CHCl3 (25 ml) before washing twice with 10% aqueous NaHCO3 (20 ml). The organic phase was dried (MgSO4) and evaporated. The crude product was dissolved in hexane, and insoluble impurities were removed. The hexane solution was then treated with activated charcoal, to give a colourless liquid. Evaporation of the solvent gave white or weakly pink crystals. The yield was 3.8 g, 35% of the theoretical. 1H- and 13C NMR (CDCl3), d (ppm) rel. to TMS: 7.93 (s, 1H, CH(OAc)2) 7.49, 7.27 and 7.02 (m, 3×1H, Ar-H) and 2.12 (s, 6H, CH3); 168.386, 137.867, 127.179,126.917 and 126.599 (Ar), 86.227 (CH(OAc)2) and 20.663 (CH3).

Provenance & Evidence