Synthesis
General procedure for the synthesis of (E)-4-bromobut-2-enoic acid from crotonic acid: a mixture of (E)-but-2-enoic acid (10.00 g, 116.16 mmol), N-bromosuccinimide (NBS, 1.02 g, 118.48 mmol), and 2,2'-azobis(2-methylpropionitrile) (AIBN, 381.49 mg, 2.32 mmol ) were dissolved in carbon tetrachloride (CCl4, 120 mL) and the reaction was stirred at 90 °C for 4 hours. After completion of the reaction, the mixture was filtered and the filtrate was concentrated. The residue was recrystallized with hexane to afford the target product (E)-4-bromobut-2-enoic acid (19.17 g, 42.2% yield).
References
[1] Archiv der Pharmazie, 2014, vol. 347, # 8, p. 552 - 558
[2] Bioorganic and Medicinal Chemistry, 2014, vol. 22, # 7, p. 2366 - 2378
[3] Patent: CN107556289, 2018, A. Location in patent: Paragraph 0112; 0114; 0115; 0116
[4] Journal of Organic Chemistry, 2011, vol. 76, # 11, p. 4467 - 4481
[5] Tetrahedron Letters, 2018, vol. 59, # 18, p. 1776 - 1778
