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General procedure for the synthesis of 1H-imidazole-2-carbonitrile from 2-imidazolecarboxaldehyde: To a 1L round-bottomed flask was added a solution of 1H-imidazole-2-carboxaldehyde (5 g, 52.04 mmol) in N,N-dimethylformamide (200 mL). Triethylamine (10.8 mL, 77.97 mmol), hydroxylamine hydrochloride (3.95 g, 56.84 mmol, 1.10 eq.) and 1-propanephosphonic anhydride solution (T3P, 36.4 g, 114.40 mmol) were added sequentially. The reaction mixture was stirred at 100 °C for 4 h. After cooling, the reaction was quenched with 500 mL of ice water. The aqueous phase was extracted with ethyl acetate (3 x 1 L), the combined organic layers were washed with brine (2 x 1 L), dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with the eluent of ethyl acetate/petroleum ether (1/2) to give 2 g (41%) of the target product 1H-imidazole-2-carbonitrile as an off-white solid.

[1] Tetrahedron Letters, 2012, vol. 53, # 27, p. 3421 - 3424
[2] Bioorganic and Medicinal Chemistry Letters, 2016, vol. 26, # 13, p. 3038 - 3041
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