Synthesis
The general procedure for the synthesis of 5-bromofuran-2-carbonitrile from 5-bromo-2-furancarboxaldehyde was as follows: in a 25 mL two-necked round-bottomed flask equipped with a thermometer and a magnetic stirrer, 4 mmol of 5-bromo-2-furancarboxaldehyde (1-18), 6 mmol of NH4OAc, 4 mmol of Na2CO3, 4.4 mmol of TBHP, and 0.1 mmol of I2 were added. Subsequently, 5 mL of anhydrous ethanol was added as solvent. The reaction flask was placed in an oil bath preheated to 50 °C and a magnetic stirrer was turned on, and the reaction lasted for 4.5 hours. Upon completion of the reaction, the reaction was quenched by the addition of sodium thiosulfate solution and the mixture was extracted with ether. After separation of the organic layer, the solvent was removed by evaporation under reduced pressure. Separation was carried out by column chromatography using a mixture of ethyl acetate/petroleum ether in the ratio of 1:100, v/v, as eluent, and the eluate containing the target product, 5-bromofuran-2-carbonitrile, was collected, and the solvent was evaporated to give the pure product. The isolated yield of the reaction was 85%.
References
[1] Chemistry of Heterocyclic Compounds, 2002, vol. 38, # 5, p. 524 - 529
[2] Advanced Synthesis and Catalysis, 2016, vol. 358, # 7, p. 1157 - 1163
[3] RSC Advances, 2017, vol. 7, # 3, p. 1484 - 1489
[4] Electrochimica Acta, 2017, vol. 226, p. 53 - 59
[5] Patent: CN106748881, 2017, A. Location in patent: Paragraph 0050
