Acetic Anhydride → 4-Bromo-5-nitrothiophene-2-carbonitrile

Beteiligte Stoffe

Reaktionsschritte

A 5-L, three neck, round bottom flask equipped with a temperature probe, mechanical stirrer, and a reflux condenser was charged with 4-Bromo-5-nitro-thiophene-2-carbaldehyde oxime (Example 25: step c; 441.0 g, 1.76 mol). Acetic anhydride (2.5 L) was added causing an endothermic reaction from 22° C. to 17° C. The resulting yellow slurry was heated to reflux. At 100° C. the reaction became a black solution. After 2 hours at 130° C., TLC analysis (2:1 heptane/EtOAc) showed reaction completion and the heat was removed. The mixture was transferred to a rotary evaporator and concentrated to dryness. The residue was diluted with CH2Cl2 (3 L), and H2O (3 L). The layers were separated and the organic layer was washed with H2O (3 L), dried over MgSO4, and concentrated to give the desired title compound as a tan solid (350.85 g, 86%). 1H-NMR (DMSO): δ 8.3 (1H, s).

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